computer

Personal computer hardware

2009-10-02T03:29:00.000-07:00

A personal computer is made up of multiple physical components of computer hardware, upon which can be installed an operating system and a multitude of software to perform the operator's desired functions.

Typical PC hardware

Hardware of Personal Computer.
1. Monitor
2. Motherboard
3. CPU
4. RAM Memory
5. Expansion card
6. Power supply
7. CD-ROM Drive
8. Hard Disk
9. Keyboard
10. Mouse
Inside a custom computer.Though a PC comes in many different form factors, a typical personal computer consists of a case or chassis in a tower shape (desktop) and the following parts:

Motherboard
Components directly attached to the motherboard include:

The central processing unit (CPU) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan.
The chipset mediates communication between the CPU and the other components of the system, including main memory.
RAM Stores all running processes (applications) and the current running OS. RAM Stands for Random Access Memory
The BIOS includes boot firmware and power management. The Basic Input Output System tasks are handled by operating system drivers.
Internal Buses connect the CPU to various internal components and to expansion cards for graphics and sound.
Current
The northbridge memory controller, for RAM and PCI Express
PCI Express, for expansion cards such as graphics and physics processors, and high-end network interfaces
PCI, for other expansion cards
SATA, for disk drives
Obsolete
ATA (superseded by SATA)
AGP (superseded by PCI Express)
VLB VESA Local Bus (superseded by AGP)
ISA (expansion card slot format obsolete in PCs, but still used in industrial computers)
External Bus Controllers support ports for external peripherals. These ports may be controlled directly by the southbridge I/O controller or based on expansion cards attached to the motherboard through the PCI bus.
USB
FireWire
eSATA
SCSI
Power supply
Main article: Power supply unit (computer)
Includes power cords, switch, and cooling fan. Supplies power at appropriate voltages to the motherboard and internal disk drives. It also converts alternating current to direct current and provides different voltages to different parts of the computer.

Video display controller
Main article: Graphics card
Produces the output for the computer monitor. This will either be built into the motherboard or attached in its own separate slot (PCI, PCI-E, PCI-E 2.0, or AGP), in the form of a graphics card.

Most video cards support the most basic requirements, and video card manufacturing companies are doing a good job of keeping up with the requirements the games need. However the games are still evolving faster than the video because of manufacturing companies.

Removable media devices
Main article: Computer storage
CD (compact disc) - the most common type of removable media, suitable for music and data.
CD-ROM Drive - a device used for reading data from a CD.
CD Writer - a device used for both reading and writing data to and from a CD.
DVD (digital versatile disc) - a popular type of removable media that is the same dimensions as a CD but stores up to 12 times as much information. It is the most common way of transferring digital video, and is popular for data storage.
DVD-ROM Drive - a device used for reading data from a DVD.
DVD Writer - a device used for both reading and writing data to and from a DVD.
DVD-RAM Drive - a device used for rapid writing and reading of data from a special type of DVD.
Blu-ray Disc - a high-density optical disc format for data and high-definition video. Can store 70 times as much information as a CD.
BD-ROM Drive - a device used for reading data from a Blu-ray disc.
BD Writer - a device used for both reading and writing data to and from a Blu-ray disc.
HD DVD - a discontinued competitor to the Blu-ray format.
Floppy disk - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium. Used today mainly for loading RAID drivers.
Iomega Zip drive - an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994.
USB flash drive - a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable, and rewritable. Capacities vary, from hundreds of megabytes (in the same ballpark as CDs) to tens of gigabytes (surpassing, at great expense, Blu-ray discs).
Tape drive - a device that reads and writes data on a magnetic tape, used for long term storage and backups.
Internal storage
Hardware that keeps data inside the computer for later use and remains persistent even when the computer has no power.

Hard disk - for medium-term storage of data.
Solid-state drive - a device similar to hard disk, but containing no moving parts and stores data in a digital format.
RAID array controller - a device to manage several internal or external hard disks and optionally some peripherals in order to achieve performance or reliability improvement in what is called a RAID array.
Sound card
Main article: Sound card
Enables the computer to output sound to audio devices, as well as accept input from a microphone. Most modern computers have sound cards built-in to the motherboard, though it is common for a user to install a separate sound card as an upgrade. Most sound cards, either built-in or added, have surround sound capabilities.

Other peripherals
Main article: Peripheral
In addition, hardware devices can include external components of a computer system. The following are either standard or very common.

Wheel MouseIncludes various input and output devices, usually external to the computer system.

Input
Main article: Input
Text input devices
Keyboard - a device to input text and characters by depressing buttons (referred to as keys), similar to a typewriter. The most common English-language key layout is the QWERTY layout.
Pointing devices
Mouse - a pointing device that detects two dimensional motion relative to its supporting surface.
Optical Mouse - a newer technology that uses lasers, or more commonly LEDs to track the surface under the mouse to determine motion of the mouse, to be translated into mouse movements on the screen.
Trackball - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
Gaming devices
Joystick - a general control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions.
Gamepad - a general handheld game controller that relies on the digits (especially thumbs) to provide input.
Game controller - a specific type of controller specialized for certain gaming purposes.
Image, Video input devices
Image scanner - a device that provides input by analyzing images, printed text, handwriting, or an object.
Webcam - a low resolution video camera used to provide visual input that can be easily transferred over the internet.
Audio input devices
Microphone - an acoustic sensor that provides input by converting sound into electrical signals.

Computer

2009-09-27T06:38:00.000-07:00

Computer Technology Limited [CTL] was a British company founded by Ian Barron in the late 1960s to manufacture and sell an innovative minicomputer system.

CTL employed some innovative human relations procedures (13 pay periods, pay 4 weeks in advance, a very flat organizational structure.) It was founded slightly later than Digital Equipment Corporation (DEC) in the United States, and was also a rival of Elliot Computing. Barron had worked for Elliot but left to found CTL when he couldn't persuade Elliot to incorporate his ideas in their next generation of computers. He left CTL in 1971 and later created Inmos and developed the transputer.

The first CTL computer (the Modular One) appeared for sale in 1969. The Modular One was a 16-bit computer built with Emitter Coupled Logic (ECL) and was competitive with other first generation minicomputers. Its most distinctive hardware features were memory-mapped I/O, and an early version of segmented memory (similar to the later Intel 8086 but having both base and limit). The latter, together with two execution states (Normal State and Special State) made possible the implementation of a self-protecting operating system kernel (known as the Executive, or Exec). Such ideas were popular in British computer academia at the time and later were adopted by some US designs such as the aforementioned Intel 8086. Also, the power system was set up as a peripheral with interrupt capabilities which gave the machine the ability to power down gracefully in an emergency.

The Exec was known as E4. (E1, E2 and E3 were much simpler execs used only in the first few years of the company). E4 was based on an early version of object-oriented principles, though lacking most of what are now considered essential features of the paradigm. Objects included Activities (now more commonly known as tasks or processes), Segments (of memory), Files, Semaphores and Clocks. Another object type, the Sphere, was a run-time protection domain within which all other object types (including other Spheres) existed. There was some similarity to Unix in the use of serial byte oriented streams in the file system and interprocess communication, in contrast to the record-oriented file systems then dominant in commercial data processing. E4 also supported real-time priorities and virtual memory at the Segment level. It was a relatively elegant OS for its time but was never ported to other hardware, having been written entirely in assembler. (Appropriate and effective high-level language implementations were not readily available at the time.)

The Modular One was comparatively expensive. It was somewhat exotic in that its modular design resulted in almost every system delivered being somewhat different, which created a high maintenance burden. It never sold widely outside of the UK, and even in the UK it was surpassed in sales by DEC and Data General before the end of the 1970s. The systems were cost reduced with new technology over the mid '70s to mid '80s but never gained a significant market share. During the mid '80s, the company realised that the future lay in open systems and attempted to make the transition to Unix with re-badged systems from Motorola and Sequoia, however, sales of the proprietary systems fell off before the new systems could be ramped up to replace them, and the company was taken over by ACT in late 1989.

Computer

2009-09-20T03:34:00.000-07:00

A programmable machine. The two principal characteristics of a computer are:
It responds to a specific set of instructions in a well-defined manner.
It can execute a prerecorded list of instructions (a program).
Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.

All general-purpose computers require the following hardware components:

memory : Enables a computer to store, at least temporarily, data and programs.
mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.
input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.
output device : A display screen, printer, or other device that lets you see what the computer has accomplished.
central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.
In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.

Computers can be generally classified by size and power as follows, though there is considerable overlap:

personal computer : A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.
workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.
minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.
mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.
supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.

Computer

2009-09-13T00:19:00.000-07:00

Web Designing

2009-09-07T23:04:00.000-07:00

In software engineering, a web application or webapp is an application that is accessed via a web browser over a network such as the Internet or an intranet. It is also a computer software application that is coded in a browser-supported language (such as HTML, JavaScript, Java, etc.) and reliant on a common web browser to render the application executable.

Web applications are popular due to the ubiquity of web browsers, and the convenience of using a web browser as a client, sometimes called a thin client. The ability to update and maintain web applications without distributing and installing software on potentially thousands of client computers is a key reason for their popularity, as is the inherent support for cross-platform compatibility. Common web applications include webmail, online retail sales, online auctions, wikis and many other functions.
History
In earlier types of client-server computing, each application had its own client program which served as its user interface and had to be separately installed on each user's personal computer. An upgrade to the server part of the application would typically require an upgrade to the clients installed on each user workstation, adding to the support cost and decreasing productivity.

In contrast, web applications use web documents written in a standard format such as HTML (and more recently XHTML), which are supported by a variety of web browsers.

Generally, each individual web page is delivered to the client as a static document, but the sequence of pages can provide an interactive experience, as user input is returned through web form elements embedded in the page markup. During the session, the web browser interprets and displays the pages, and acts as the universal client for any web application.

In 1995, Netscape introduced a client-side scripting called JavaScript, which allowed programmers to add some dynamic elements to the user interface that ran on the client side. Until then, all the data had to be sent to the server for processing, and the results were delivered through static HTML pages sent back to the client.

In 1996, Macromedia introduced Flash, a vector animation player that could be added to browsers as a plugin to embed animations on the web pages. It allowed the use of a scripting language to program interactions on the client side with no need to communicate with the server.

In 1999, the "web application" concept was introduced in the Java language in the Servlet Specification version 2.2. [2.1?].At that time both JavaScript and XML had already been developed, but AJAX had still not yet been coined and the XMLHttpRequest object had only been recently introduced on Internet Explorer 5 as an ActiveX object.

In 2005, AJAX was coined, and applications like Gmail started to make their client sides more and more interactive.

Interface

Webconverger operating system provides an interface for web applications.The web interface places very few limits on client functionality. Through Java, JavaScript, DHTML, Flash and other technologies, application-specific methods such as drawing on the screen, playing audio, and access to the keyboard and mouse are all possible. Many services have worked to combine all of these into a more familiar interface that adopts the appearance of an operating system. General purpose techniques such as drag and drop are also supported by these technologies. Web developers often use client-side scripting to add functionality, especially to create an interactive experience that does not require page reloading. Recently, technologies have been developed to coordinate client-side scripting with server-side technologies such as PHP. Ajax, a web development technique using a combination of various technologies, is an example of technology which creates a more interactive experience.

Structure
Applications are usually broken into logical chunks called "tiers", where every tier is assigned a role.[4] Traditional applications consist only of 1 tier, which resides on the client machine, but web applications lend themselves to a n-tiered approach by nature.[4] Though many variations are possible, the most common structure is the three-tiered application.[4] In its most common form, the three tiers are called presentation, application and storage, in this order. A web browser is the first tier (presentation), an engine using some dynamic Web content technology (such as ASP, ASP.NET, CGI, ColdFusion, JSP/Java, PHP, Perl, Python, Ruby on Rails or Struts2) is the middle tier (application logic), and a database is the third tier (storage).[4] The web browser sends requests to the middle tier, which services them by making queries and updates against the database and generates a user interface.

For more complex applications, a 3-tier solution may fall short, and you may need a n-tiered approach, where the greatest benefit is breaking the business logic, which resides on the application tier, into a more fine-grained model.[4] For example, creating a separate business logic tier. Or adding an integration tier that separates the data tier from the rest of tiers by providing an easy-to-use interface to access the data. For example, you would access the client data by calling a "list_clients()" function instead of making a SQL query directly against the client table on the database. That allows you to replace the underlying database without changing the other tiers.

There are some who view a web application as a two-tier architecture. This can be a "smart" client that performs all the work and queries a "dumb" server, or a "dumb" client that relies on a "smart" server. The client would handle the presentation tier, the server would have the database (storage tier), and the business logic (application tier) would be on one of them or on both. While this increases the scalability of the applications and separates the display and the database, it still doesn't allow for true specialization of layers, so most applications will outgrow this model.

Business use
An emerging strategy for application software companies is to provide web access to software previously distributed as local applications. Depending on the type of application, it may require the development of an entirely different browser-based interface, or merely adapting an existing application to use different presentation technology. These programs allow the user to pay a monthly or yearly fee for use of a software application without having to install it on a local hard drive. A company which follows this strategy is known as an application service provider (ASP), and ASPs are currently receiving much attention in the software industry.

Writing web applications
There are many web application frameworks which facilitate rapid application development by allowing the programmer to define a high-level description of the program. In addition, there is potential for the development of applications on Internet operating systems, although currently there are not many viable platforms that fit this model.

The use of web application frameworks can often reduce the number of errors in a program, both by making the code simpler, and by allowing one team to concentrate just on the framework. In applications which are exposed to constant hacking attempts on the Internet, security-related problems caused by errors in the program are a big issue. Frameworks may also promote the use of best practices such as GET after POST.

Applications
Browser applications typically include simple office software (word processors, online spreadsheets, and presentation tools), with Google Docs being the most notable example, and can also include more advanced applications such as project management, computer-aided design, video editing and point-of-sale

Benefits
Browser applications typically require little or no disk space on the client, upgrade automatically with new features, integrate easily into other web procedures, such as email and searching. They also provide cross-platform compatibility (i.e., Windows, Mac, Linux, etc.) because they operate within a web browser window.

Drawbacks
Standards compliance is an issue with any non-typical office document creator, which causes problems when file sharing and collaboration becomes critical. Also, browser applications rely on application files accessed on remote servers through the Internet. Therefore, when connection is interrupted, the application is no longer usable. Google Gears is a platform to ameliorate this issue and improve the usability of browser applications.

Web Designing

2009-09-01T22:17:00.000-07:00

A website (or web site) is a collection of related webpages (or web pages), images, videos or other digital assets that are addressed with a common domain name or IP address in an Internet Protocol-based network. A web site is hosted on at least one web server, accessible via the Internet or a private local area network.

A webpage is a document, typically written in plain text interspersed with formatting instructions of Hypertext Markup Language (HTML, XHTML). A webpage may incorporate elements from other websites with suitable markup anchors.

Webpages are accessed and transported with the Hypertext Transfer Protocol (HTTP), which may optionally employ encryption (HTTP Secure, HTTPS) to provide security and privacy for the user of the webpage content. The user's application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal.

All publicly accessible websites collectively constitute the World Wide Web.

The pages of a website can usually be accessed from a simple Uniform Resource Locator (URL) called the homepage. The URLs of the pages organize them into a hierarchy, although hyperlinking between them conveys the reader's perceived site structure and guides the reader's navigation of the site.

Some websites require a subscription to access some or all of their content. Examples of subscription sites include many business sites, parts of many news sites, academic journal sites, gaming sites, message boards, web-based e-mail, services, social networking websites, and sites providing real-time stock market data.

History
The World Wide Web was created in 1989 by CERN engineer Tim Berners-Lee. On 30 April 1993, CERN announced that the World Wide Web would be free to use for anyone.

Before the introduction of HTML and HTTP other protocols such as file transfer protocol and the gopher protocol were used to retrieve individual files from a server. These protocols offer a simple directory structure which the user navigates and chooses files to download. Documents were most often presented as plain text files without formatting or were encoded in word processor formats.

Overview
Organized by function, a website may be

a personal website
a commercial website
a government website
a non-profit organization website
It could be the work of an individual, a business or other organization, and is typically dedicated to some particular topic or purpose. Any website can contain a hyperlink to any other website, so the distinction between individual sites, as perceived by the user, may sometimes be blurred.

Websites are written in, or dynamically converted to, HTML (Hyper Text Markup Language) and are accessed using a software interface classified as a user agent. Web pages can be viewed or otherwise accessed from a range of computer-based and Internet-enabled devices of various sizes, including desktop computers, laptops, PDAs and cell phones.

A website is hosted on a computer system known as a web server, also called an HTTP server, and these terms can also refer to the software that runs on these systems and that retrieves and delivers the web pages in response to requests from the website users. Apache is the most commonly used web server software (according to Netcraft statistics) and Microsoft's Internet Information Server (IIS) is also commonly used.

Website styles

Static website
A static website is one that has web pages stored on the server in the format that is sent to a client web browser. It is primarily coded in Hypertext Markup Language (HTML).

Simple forms or marketing examples of websites, such as classic website, a five-page website or a brochure website are often static websites, because they present pre-defined, static information to the user. This may include information about a company and its products and services via text, photos, Flash animation, audio/video and interactive menus and navigation.

This type of website usually displays the same information to all visitors. Similar to handing out a printed brochure to customers or clients, a static website will generally provide consistent, standard information for an extended period of time. Although the website owner may make updates periodically, it is a manual process to edit the text, photos and other content and may require basic website design skills and software.

In summary, visitors are not able to control what information they receive via a static website, and must instead settle for whatever content the website owner has decided to offer at that time.

They are edited using four broad categories of software:

Text editors, such as Notepad or TextEdit, where content and HTML markup are manipulated directly within the editor program
WYSIWYG offline editors, such as Microsoft FrontPage and Adobe Dreamweaver (previously Macromedia Dreamweaver), with which the site is edited using a GUI interface and the final HTML markup is generated automatically by the editor software
WYSIWYG online editors, where any media rich online presentation like websites, widgets, intro, blogs etc. are created on a flash based platform
Template-based editors, such as Rapidweaver and iWeb, which allow users to quickly create and upload websites to a web server without having to know anything about HTML, as they just pick a suitable template from a palette and add pictures and text to it in a DTP-like fashion without ever having to see any HTML code

Dynamic website
A dynamic website is one that changes or customizes content automatically and/or frequently based on certain criteria. The page composition is usually data-driven and collates information ad hoc each time a page is requested.

A website can be dynamic in one of two ways. The first is that the web page code is constructed dynamically. The second is that the web page content displayed varies based on certain criteria. The criteria may be pre-defined rules or may be based on variable user input.

The main purpose of a dynamic website is that it is much simpler to maintain a few template pages and a database than it is to build and update hundreds or thousands of individual web pages and links.

A dynamic website also describes its construction or how it is built, and more specifically refers to the code used to create a single web page. A dynamic web page is generated on the fly by piecing together certain blocks of code, procedures or routines. A dynamically-generated web page would call various bits of information from a database and put them together in a pre-defined format to present the reader with a coherent page. It interacts with users in a variety of ways including by reading cookies recognizing users' previous history, session variables, server side variables etc., or by using direct interaction (form elements, mouseovers, etc.). A site can display the current state of a dialogue between users, monitor a changing situation, or provide information in some way personalized to the requirements of the individual user.

Some countries, for example the U.K. and the U.S., have introduced legislation regarding web accessibility.

Software systems
There are a wide range of software systems, such as Java Server Pages (JSP), the PHP and Perl programming languages, Active Server Pages (ASP), YUMA and Cold Fusion (CFM) that are available to generate dynamic web systems and dynamic sites. Sites may also include content that is retrieved from one or more databases or by using XML-based technologies such as RSS.

Static content may also be dynamically generated either periodically, or if certain conditions for regeneration occur (cached) in order to avoid the performance loss of initiating the dynamic engine on a per-user or per-connection basis.

Plug ins are available to expand the features and abilities of web browsers, which use them to show active content, such as Flash, Shockwave or applets written in Java. Dynamic HTML also provides for user interactivity and realtime element updating within web pages (i.e., pages don't have to be loaded or reloaded to effect any changes), mainly using the DOM and JavaScript, support which is built-in to most modern web browsers.

Turning a website into an income source is a common practice for web developers and website owners. There are several methods for creating a website business which fall into two broad categories, as defined below.

Content-based sites
Some websites derive revenue by selling advertising space on the site (see contextual ads).

Product- or service-based sites
Some websites derive revenue by offering products or services for sale. In the case of e-commerce websites, the products or services may be purchased at the website itself, by entering credit card or other payment information into a payment form on the site. While most business websites serve as a shop window for existing brick and mortar businesses, it is increasingly the case that some websites are businesses in their own right; that is, the products they offer are only available for purchase on the web.

Websites occasionally derive income from a combination of these two practices. For example, a website such as an online auctions website may charge the users of its auction service to list an auction, but also display third-party advertisements on the site, from which it derives further income.

Spelling
As noted above, there are several different spellings for this term. Although website and web site are commonly used (the former especially in British English), the Associated Press Style book, Reuters, Microsoft, academia, book publishing, The Chicago Manual of Style, and dictionaries such as Merriam-Webster use the two-word, initially capitalized spelling Web site. This is because "Web" is not a general term but a shortened form of World Wide Web. As with many newly created terms, it may take some time before a common spelling is finalized. (This controversy also applies to derivative terms such as Web master/webmaster and Web cam/webcam).

The Canadian Oxford Dictionary and the Canadian Press Style book list "website" and "web page" as the preferred spellings. The Oxford English Dictionary began using "website" as its standardized form in 2004.

Bill Walsh, the copy chief of The Washington Post's national desk, and one of American English's foremost grammarians, argues for the two-word spelling with capital W in his books Lapsing into a Comma and The Elephants of Style, and on his site, the Slot.

Types of websites
There are many varieties of websites, each specializing in a particular type of content or use, and they may be arbitrarily classified in any number of ways. A few such classifications might include:[original research?]

Affiliate: enabled portal that renders not only its custom CMS but also syndicated content from other content providers for an agreed fee. There are usually three relationship tiers. Affiliate Agencies (e.g., Commission Junction), Advertisers (e.g., eBay) and consumer (e.g., Yahoo!).
Archive site: used to preserve valuable electronic content threatened with extinction. Two examples are: Internet Archive, which since 1996 has preserved billions of old (and new) web pages; and Google Groups, which in early 2005 was archiving over 845,000,000 messages posted to Usenet news/discussion groups.
Blog (or web log) site: sites generally used to post online diaries which may include discussion forums (e.g., blogger, Xanga).
Content site: sites whose business is the creation and distribution of original content (e.g., Slate, About.com).
Corporate website: used to provide background information about a business, organization, or service.
Electronic commerce (eCommerce) site: a site offering goods and services for online sale and enabling online transactions for such sales.
Community site: a site where persons with similar interests communicate with each other, usually by chat or message boards, such as MySpace or Facebook.
City Site: A site that shows information about a certain city or town and events that takes place in that town. Usually created by the city council or other "movers and shakers".
the same as those of geographic entities, such as cities and countries. For example, Richmond.com is the geodomain for Richmond, Virginia.
Gripe site: a site devoted to the critique of a person, place, corporation, government, or institution.
Forum: a site where people can sign up and discuss different topics.
Humor site: satirizes, parodies or otherwise exists solely to amuse.
Information site: contains content that is intended to inform visitors, but not necessarily for commercial purposes, such as: RateMyProfessors.com, Free Internet Lexicon and Encyclopedia. Most government, educational and non-profit institutions have an informational site.
Java applet site: contains software to run over the Web as a Web application.
Mirror site: A complete reproduction of a website.
News site: similar to an information site, but dedicated to dispensing news and commentary.
Personal homepage: run by an individual or a small group (such as a family) that contains information or any content that the individual wishes to include. These are usually uploaded using a web hosting service such as Geocities.
Phish site: a website created to fraudulently acquire sensitive information, such as passwords and credit card details, by masquerading as a trustworthy person or business (such as Social Security Administration, PayPal) in an electronic communication (see Phishing).
Political site: A site on which people may voice political views.
Porn site: A site that shows sexually explicit content for enjoyment and relaxation, most likely in the form of an internet gallery, dating site, blog, social networking, or video sharing.
Rating site: A site on which people can praise or disparage what is featured.
Review site: A site on which people can post reviews for products or services.
School site: a site on which teachers, students, or administrators can post information about current events at or involving their school. U.S. elementary-high school websites generally use k12 in the URL, such as kearney.k12.mo.us.
Social networking site: a site where users could communicate with one another and share media, such as pictures, videos, music, blogs, etc. with other users. These may include games and web applications.
Social bookmarking site: a site where users share other content from the internet and rate and comment on the content. StumbleUpon and Digg are examples.
Video sharing: A site that enables user to upload videos, such as YouTube and Google Video.
Search engine site: a site that provides general information and is intended as a gateway or lookup for other sites. A pure example is Google, and the most widely known extended type is Yahoo!.
Shock site: includes images or other material that is intended to be offensive to most viewers (e.g. rotten.com).
Warez: a site designed to host and let users download copyrighted materials illegally.
Web portal: a site that provides a starting point or a gateway to other resources on the Internet or an intranet.
Wiki site: a site which users collaboratively edit (such as Wikipedia and Wikihow).
Some websites may be included in one or more of these categories. For example, a business website may promote the business's products, but may also host informative documents, such as white papers. There are also numerous sub-categories to the ones listed above. For example, a porn site is a specific type of eCommerce site or business site (that is, it is trying to sell memberships for access to its site). A fan site may be a dedication from the owner to a particular celebrity.

Websites are constrained by architectural limits (e.g., the computing power dedicated to the website). Very large websites, such as Yahoo!, Microsoft, and Google employ many servers and load balancing equipment such as Cisco Content Services Switches to distribute visitor loads over multiple computers at multiple locations.

In February 2009, Netcraft, an Internet monitoring company that has tracked Web growth since 1995, reported that there were 215,675,903 websites with domain names and content on them in 2009, compared to just 18,000 websites in August 1995.

Web Designing

2009-08-27T21:19:00.000-07:00

Website architecture is an approach to the design and planning of websites which, like architecture itself, involves technical, aesthetic and functional criteria. As in traditional architecture, the focus is properly on the user and on user requirements. This requires particular attention to web content, a business plan, usability, interaction design, information architecture and web design. For effective search engine optimization it is necessary to have an appreciation of how a single website relates to the World Wide Web.
Since web content planning, design and management come within the scope of design methods, the traditional vitruvian aims of commodity, firmness and delight can guide the architecture of websites, as they do physical architecture and other design disciplines. Website architecture is coming within the scope of aesthetics and critical theory and this trend may accelerate with the advent of the semantic web and web 2.0. Both ideas emphasise the structural aspects of information. Structuralism is an approach to knowledge which has influenced a number of academic disciplines including aesthetics, critical theory and postmodernism. Web 2.0, because it involves user-generated content, directs the website architect's attention to the structural aspects of information.
"Website architecture" has the potential to be a term used for the intellectual discipline of organizing website content. "Web design", by way of contrast, describes the practical tasks, part-graphic and part-technical, of designing and publishing a website. The distinction compares to that between the task of editing a newspaper or magazine and its graphic design and printing. But the link between editorial and production activities is much closer for web publications than for print publications.

Website design styles
Over the short history of the web, various architectural and artistic styles have developed among different online language, national, social and cultural communities. Such differences in website design styles would set European websites apart from North American ones, Taiwanese websites from the ones originated in Mainland China (marked by the tendency to proliferate pop-up windows activated by left-click), Japanese (marked by employment of bright colors and flashing cute anime characters) from Korean (marked by gray text-white background, clean, "MacIntosh"-style interface). Especially innovative is a style originated in the Netherlands and other Dutch-speaking online communities, of the web interface heavily drawing on flash and postmodern visual arts at the expense of text and ordinary functionality.

Web Designing

2009-08-21T00:44:00.000-07:00

An introduction to domain names, web servers, and website hosting
I assume that you know nothing about the inner workings of the Internet; maybe you're not even sure how people actually get to web sites, where the web sites are actually sitting, what the web is in the first place....
In this article I am going to give you the minimum you need to get your 'feet wet' so that we can quickly get into building web sites. I won't go into painful micro-details that would put all but true nerds to sleep, again there is just enough so that you have a basic understanding of what's going on.

What is the web?
In a nutshell, the web is a whole bunch on interconnected computers talking to one another. The computers (on the web) are typically connected by phone lines, digital satellite signals, cables, and other types of data-transfer mechanisms. A 'data-transfer mechanism' is a nerd's way of saying: a way to move information from point A to point B to point C and so on.
The computers that make up the web can be connected all the time (24/7), or they can be connected only periodically. The computers that are connected all the time are typically called a 'server'. Servers are computers just like the one you're using now to read this article, with one major difference, they have a special software installed called 'server' software.

What is the function of server software / programs?
Server software is created to 'serve' web pages and web sites. Basically, the server computer has a bunch of web sites loaded on it and it just waits for people (via web browsers) to request or ask for a particular page. When the browser requests a page the server sends it out.

How does the web surfer find a web site?
The short answer is: by typing in the URL, or in other words, the web site address. So for example, if you wanted to find the web site www.killersites.com, you would type in the address into your web browser's address bar or maybe use your 'favorites' or 'bookmarks' link to Killersites.
There are other ways to find web sites (like search engines,) but behind the scenes web sites are all being found by going to the web site's official address. That brings us our last nerd detail: how does a website get an official address so that the rest of the web can find it?

Registering your domain name
If you ever wondered what the heck registering a domain was all about ... you probably figured it out by now! But just in case - registering a domain name gets you an official address for your web site on the World Wide Web. With this 'official' address, the rest of the web can find you.
Like your home address is unique in the real world, there also can't be any duplicate addresses on the Internet, otherwise no one would know where to go! In other words, domain names are unique addresses on the web.

Why does registering a domain name cost money?
If you want to have your own unique address on the web, your own domain name, it will cost a few bucks for each year you want to 'own' the name. The cost of registering a domain name ranges from less than $10 USD to about $30 USD per year. You can register a domain from 1 to 10 years.
The reason for the cost is that the central 'address book' of all the world's domain names needs to be updated - somebody's got to pay for that! You may have noticed that I just snuck in a little extra piece of information: the giant 'web address book' of domains.
That leads us to our last bit of nerd information: when you type in a website's domain name or click on a link that takes you to that domain name, your browser starts asking servers where that particular domain name is sitting (on the web) and the servers are then able to tell the browser where to go by referring to the giant address book I mentioned above.

Web designing

2009-08-18T03:48:00.000-07:00

The definition of “Web Design” can vary, depending on who you ask. Web designers working for one company may perform different tasks than Web designers working for another company. The basic answer is that Web design is the design of a Web page or Website, including the information and user interface design, but not including programming. Programming falls under the definition of Web development, or Web application programming (to name two of many).
At a smaller company, with fewer people and more overlap of job descriptions, Web design can be defined as the whole production of the Website from start to finish. To clarify this a bit, let’s outline the process of creating a Website from scratch.

1. DiscoveryIn this step, the Web designer finds out as much about the company and its clients as possible, paying special attention to the user audience of the Website.

2. Planning
Project definition documents are created as a guide to the creation of the Website. It is important that the scope, audience and goals of the Website are clearly defined during this stage, so the resulting project definition can be used as a touchstone to keep everyone on track throughout the process.

3. Information DesignHow will the information be broken down and presented to the user? If what the user will be looking for is well defined in the discovery and planning stages, this will be an easier job. The information design, or information architecture, step includes design of the navigation and is the most critical step in making the Website user-friendly.

4. Graphic Design
Graphic design may seem trivial to some, but it is also a very important factor in the usability of the Website. It isn’t just about making the Website look pretty. It is also about visual balance and readable typography, both of which are critical in the creation of a user-friendly Web design.

When these steps have been completed, you have a finished Web design. Loosely speaking, putting it together is called Web production, and making it work is called Web development.

Website Design and Marketing Agency Bournemouth, Manchester, UK

Website design is effective when your brand comes alive as an interactive experience, so you need an award winning website design agency to create and implement effective ideas. Our digital designers have years of experience, that's why we don't do print - just usable and engaging website design.

We realise your choice of agency will make or break your online strategy, so our company has a structured approach to web design and development, all tied together with an experienced project manager.

As a full-service website marketing company with UK offices in Bournemouth and Manchester, we offer the complete service from concept to creative web design, web development and online marketing such as search engine optimisation, pay per click campaigns and email marketing. Integration is the key so our online marketing specialists work closely with the website design team to ensure a strong, consistent result.

Website design has to create impact within seconds of arriving on the page, so you're no doubt eager to view our website design portfolio and see how our award winning ideas have worked out for clients like The BBC, Peugeot and 3M.
Website design and marketing services

Content managed website design (CMS)We offer a PHP and .net CMS website solution to give you control over updating your website content from a web browser at any time. For the .net solution, we partner with Immediacy, one of the UK's leading website content management solution providers.

For SME companies requiring a basic content managed website, we can offer a fully bespokely designed and built website, hosted for 1 year on a shared server for under £5000+VAT.

Bespoke PHP website development We can provide a quote for your bespoke website development. A blog? A forum? Secure customer login areas? Any form of custom website development can be quoted for - just contact us for details.
E-commerce website design and developmentWe are experienced in building e-commerce websites whether it be a full site with hundreds of products and categories, or just a payment processing facility added onto your website.
Search engine optimised websitesSearch engine optimisation is essential if you wish your website to generate new business leads. If you choose this option, our in-house SEO experts work closely with our website designers to build an SEO campaign and ensure your website is search engine optimised for relevant keywords.
Website hostingThrough our experienced partners we offer Linux and Windows website hosting, on a shared or dedicated server. We provide website hosting for both small websites up to large organisations such as Cunard - coping with massive traffic bursts for virtual tours during marketing campaigns.

Web Designing

2009-08-15T21:00:00.000-07:00

Web design is the skill of creating presentations of content (usually hypertext or hypermedia) that is delivered to an end-user through the World Wide Web, by way of a Web browser or other Web-enabled software like Internet television clients, microblogging clients and RSS readers.
The process of designing Web pages, Web sites, Web applications or multimedia for the Web may utilize multiple disciplines, such as animation, authoring, communication design, corporate identity, graphic design, human-computer interaction, information architecture, interaction design, marketing, photography, search engine optimization and typography.
Markup languages (such as HTML, XHTML and XML)
Style sheet languages (such as CSS and XSL)
Client-side scripting (such as JavaScript)
Server-side scripting (such as PHP and ASP)
Database technologies (such as MySQL and PostgreSQL)
Multimedia technologies (such as Flash and Silverlight)
Web pages and Web sites can be static pages, or can be programmed to be dynamic pages that automatically adapt content or visual appearance depending on a variety of factors, such as input from the end-user, input from the Webmaster or changes in the computing environment (such as the site's associated database having been modified).
With growing specialization within communication design and information technology fields, there is a strong tendency to draw a clear line between web design specifically for web pages and web development for the overall logistics of all web-based services.

Contents
1 Accessible Web design
2 History
3 Website planning
3.1 Context
3.2 Purpose
3.3 Audience
3.4 Content
3.5 Compatibility and restrictions
3.6 Planning documentation
4 Website design
4.1 Multidisciplinary requirements
4.2 Issues
4.3 Environment
4.4 Collaboration
4.5 Form versus function
4.6 Layout
4.7 Device
4.8 Tableless Web design
5 See also
6 References
7 External links

Accessible Web design
Web accessibility
To be accessible, web pages and sites must conform to certain accessibility principles. These accessibility principles are known as the WCAG when talking about content. These can be grouped into the following main areas.
Use semantic markup that provides a meaningful structure to the document (i.e. web page)
Semantic markup also refers to semantically organizing the web page structure and publishing web services description accordingly so that they can be recognized by other web services on different web pages. Standards for semantic web are set by IEEE
Use a valid markup language that conforms to a published DTD or Schema
Provide text equivalents for any non-text components (e.g. images, multimedia)
Use hyperlinks that make sense when read out of context. (e.g. avoid "Click Here.")
Don't use frames
Use CSS rather than HTML tables for layout.
Author the page so that when the source code is read line-by-line by user agents (such as a screen readers) it remains intelligible. (Using tables for design will often result in information that is not.
However, W3C permits an exception where tables for layout either make sense when linearized or an alternate version (perhaps linearized) is made available.
Website accessibility is also changing as it is impacted by Content Management Systems that allow changes to be made to webpages without the need of obtaining programming language knowledge.

History
Tim Berners-Lee published what is considered to be the first website in August 1991.Berners-Lee was the first to combine Internet communication (which had been carrying email and the Usenet for decades) with hypertext (which had also been around for decades, but limited to browsing information stored on a single computer, such as interactive CD-ROM design). Websites are written in a markup language called HTML, and early versions of HTML were very basic, only giving a website's basic structure (headings and paragraphs), and the ability to link using hypertext. This was new and different from existing forms of communication - users could easily navigate to other pages by following hyperlinks from page to page.
As the Web and web design progressed, the markup language changed to become more complex and flexible, giving the ability to add objects like images and tables to a page. Features like tables, which were originally intended to be used to display tabular information, were soon subverted for use as invisible layout devices. With the advent of Cascading Style Sheets (CSS), table-based layout is commonly regarded as outdated. Database integration technologies such as server-side scripting and design standards like W3C further changed and enhanced the way the Web is made. As times change, websites are changing the code on the inside and visual design on the outside with ever-evolving programs and utilities.
With the progression of the Web, tens of thousands of web design companies have been established around the world to serve the growing demand for such work. As with much of the information technology industry, many web design companies have been established in technology parks in the developing world as well as many Western design companies setting up offices in countries such as India, Romania, and Russia to take advantage of the relatively lower labor rates found in such countries.

Website planning
Purposing web design is a complex, but essential ongoing activity. Before creating and uploading a website, it is important to take the time to plan exactly what is needed in the website. Thoroughly considering the audience or target market, as well as defining the purpose and deciding what content will be developed, are extremely important.

Context
Web design is similar (in a very simplistic way) to traditional print publishing. Every website is an information display container, just as a book; and every web page is like the page in a book. However, web design uses a framework based on digital code and display technology to construct and maintain an environment to distribute information in multiple formats. Taken to its fullest potential, web design is undoubtedly the most sophisticated and increasingly complex method to support communication in today's world.

Purpose
It is essential to define the purpose of the website as one of the first steps in the planning process. A purpose statement should show focus based on what the website will accomplish and what the users will get from it. A clearly defined purpose will help the rest of the planning process as the audience is identified and the content of the site is developed. Setting short and long term goals for the website will help make the purpose clear and plan for the future when expansion, modification, and improvement will take place. Goal setting practices and measurable objectives should be identified to track the progress of the site and determine success.

Audience
Defining the audience is a key step in the website planning process. The audience is the group of people who are expected to visit your website – the market being targeted. These people will be viewing the website for a specific reason and it is important to know exactly what they are looking for when they visit the site. A clearly defined purpose or goal of the site as well as an understanding of what visitors want to do or feel when they come to your site will help to identify the target audience. Upon considering who is most likely to need or use the content, a list of characteristics common to the users such as:
Audience Characteristics
Information Preferences
Computer Specifications
Web Experience
Taking into account the characteristics of the audience will allow an effective website to be created that will deliver the desired content to the target audience.

Content
Content evaluation and organization requires that the purpose of the website be clearly defined. Collecting a list of the necessary content then organizing it according to the audience's needs is a key step in website planning. In the process of gathering the content being offered, any items that do not support the defined purpose or accomplish target audience objectives should be removed. It is a good idea to test the content and purpose on a focus group and compare the offerings to the audience needs. The next step is to organize the basic information structure by categorizing the content and organizing it according to user needs. Each category should be named with a concise and descriptive title that will become a link on the website. Planning for the site's content ensures that the wants or needs of the target audience and the purpose of the site will be fulfilled.

Compatibility and restrictions
Because of the market share of modern browsers (depending on your target market), the compatibility of your website with the viewers is restricted. For instance, a website that is designed for the majority of websurfers will be limited to the use of valid XHTML 1.0 Strict or older, Cascading Style Sheets Level 1, and 1024x768 display resolution. This is because Internet Explorer is not fully W3C standards compliant with the modularity of XHTML 1.1 and the majority of CSS beyond 1. A target market of more alternative browser (e.g. Firefox, Safari and Opera) users allow for more W3C compliance and thus a greater range of options for a web designer.
Another restriction on webpage design is the use of different Image file formats. The majority of users can support GIF, JPEG, and PNG (with restrictions). Again Internet Explorer is the major restriction here, not fully supporting PNG's advanced transparency features, resulting in the GIF format still being the most widely used graphic file format for transparent images.
Many website incompatibilities go unnoticed by the designer and unreported by the users. The only way to be certain a website will work on a particular platform is to test it on that platform.

Planning documentation
Documentation is used to visually plan the site while taking into account the purpose, audience and content, to design the site structure, content and interactions that are most suitable for the website. Documentation may be considered a prototype for the website – a model which allows the website layout to be reviewed, resulting in suggested changes, improvements and/or enhancements. This review process increases the likelihood of success of the website.
The first step may involve information architecture in which the content is categorized and the information structure is formulated. The information structure is used to develop a document or visual diagram called a site map. This creates a visual of how the web pages or content will be interconnected, and may help in deciding what content will be placed on what pages.
In addition to planning the structure, the layout and interface of individual pages may be planned using a storyboard. In the process of storyboarding, a record is made of the description, purpose and title of each page in the site, and they are linked together according to the most effective and logical diagram type. Depending on the number of pages required for the website, documentation methods may include using pieces of paper and drawing lines to connect them, or creating the storyboard using computer software.
Some or all of the individual pages may be designed in greater detail as a website wireframe, a mock up model or comprehensive layout of what the page will actually look like. This is often done in a graphic program, or layout design program. The wireframe has no working functionality, only planning, though it can be used for selling ideas to other web design companies.

Website design
Web design is similar (in a very simplistic way) to traditional print publishing. Every website is an information display container, just as a book is a container; and every web page is like the page in a book. However, web design uses a framework based on digital code and display technology to construct and maintain an environment to distribute information in multiple formats. Taken to its fullest potential, web design is undoubtedly the most sophisticated and increasingly complex method to support communication in today's world. "Design Issues for the World Wide Web". public domain. World Wide Web Consortium. 2009-06-09. http://www.w3.org/DesignIssues/. Retrieved on 2009-06-10.
For the typical web sites, the basic aspects of design are:
The content: the substance, and information on the site should be relevant to the site and should target the area of the public that the website is concerned with.
The usability: the site should be user-friendly, with the interface and navigation simple and reliable.
The appearance: the graphics and text should include a single style that flows throughout, to show consistency. The style should be professional, appealing and relevant.
The visibility: the site must also be easy to find via most, if not all, major search engines and advertisement media.
A web site typically consists of text and images. The first page of a web site is known as the Home page or Index. Some web sites use what is commonly called a Splash Page. Splash pages might include a welcome message, language or region selection, or disclaimer. Each web page within a web site is an HTML file which has its own URL. After each web page is created, they are typically linked together using a navigation menu composed of hyperlinks. Faster browsing speeds have led to shorter attention spans and more demanding online visitors and this has resulted in less use of Splash Pages, particularly where commercial web sites are concerned[citation needed].
Once a web site is completed, it must be published or uploaded in order to be viewable to the public over the internet. This may be done using an FTP client. Once published, the web master may use a variety of techniques to increase the traffic, or hits, that the web site receives. This may include submitting the web site to a search engine such as Google, Bing or Yahoo, exchanging links with other web sites, creating affiliations with similar web sites, etc.

Multidisciplinary requirements
Web site design crosses multiple disciplines of multiple information systems, information technology and communication design. The web site is an information system whose components are sometimes classified as front-end and back-end. The observable content (e.g. page layout, user interface, graphics, text, audio) is known as the front-end. The back-end comprises the organization and efficiency of the source code, invisible scripted functions, and the server-side components that process the output from the front-end. Depending on the size of a Web development project, it may be carried out by a multi-skilled individual (sometimes called a web master), or a project manager may oversee collaborative design between group members with specialized skills.

Issues
By its very nature, web design is conflicted, involving rigid technical conformance and personal creative balance. Rapid technological change complicates acquiring and deploying suitable resources to maintain web presence.

Environment
Layout is a double edged sword: on the one hand, it is the expression of a framework that actively shapes the web designer. On the other hand, as the designer adapts that framework to projects, layout is the means of content delivery. Publishing a web engages communication throughout the production process as well as within the product created. Publication implies adaptation of culture and content standards. Web design incorporates multiple intersections between many layers of technical and social understanding, demanding creative direction, design element structure, and some form of social organization. Differing goals and methods resolve effectively in successful deployment of education, software and team management during the design process. However, many competing and evolving platforms and environments challenge acceptance, completion and continuity of every design product.

Collaboration
Early Web design was less integrated with companies’ advertising campaigns, customer transactions, extranets, intranets and social networking. Web sites were seen largely as static online brochures or database connection points, disconnected from the broader scopes of a business or project. Many Web sites are still disconnected from the broader project scope. As a result, many Web sites are needlessly difficult to use, indirect in their way of communicating, and suffer from a 'disconnected' or ineffective bureaucratic information architecture.

Form versus function
A web developer may pay more attention to how a page looks while neglecting other copywriting and search engine optimization functions such as the readability of text, the ease of navigating the site, or how easily the visitors are going to find the site. As a result, the designers may end up in disputes where some want more decorative graphics at the expense of keyword-rich text, bullet lists, and text links. Assuming a false dichotomy that form and function are mutually exclusive overlooks the possibility of integrating multiple disciplines for a collaborative and synergistic solution. In many cases form follows function. Because some graphics serve communication purposes in addition to aesthetics, how well a site works may depend on the graphic design ideas as well as the professional writing considerations.
When using a lot of graphics, a web page can load slowly, often irritating the user. This has become less of a problem as the internet has evolved with high-speed internet and the use of vector graphics. However there is still an ongoing engineering challenge to increase bandwidth and an artistic challenge to minimize the amount of graphics and their file sizes. This challenge is compounded since increased bandwidth encourages more graphics with larger file sizes.
When faced with a large database and many requirements, a design group may throw far too much information for a server to manage. Alternative technology or additional structure (even another server or site) may be required to fit the demand.

Layout
Layout refers to the dimensioning of content in a device display, and the delivery of media in a content related stream. Web design layouts result in visual content frameworks: these frameworks can be fixed, they can use units of measure that are relative, or they can provide fluid layout with proportional dimensions. The deployment flowchart (a useful tool on any design project) should address content layout. Many units of measure exist, but here are some popular dimension formats:
Pixel measure results in fixed or static content
Em measure results in proportional content that is relative to font-size
Percent measure results in fluid content that shrinks and grows to "fit" display windows
Proportional, liquid and hybrid layout are also referred to as dynamic design. Hybrid layout incoroprates any combination of fixed, proportional or fluid elements within (or pointing to) a single page. The hybrid web design framework is made possible by digital internet conventions generally proscribed by the W3C. If any layout does not appear as it should, it is very likely that it does not conform to standard design principles, or that those standards conflict with standard layout elements. Current knowledge of standards is essential to effective hybrid design.
The earliest web pages used fixed layouts without exception. In many business pages fixed layouts are preferred today as they easily contain static tabled information. Fixed layout enforces device display convention, as viewers must set their display to at least a certain width to easily view content. This width can include display of coporate logos, cautions, advertisements and any other target content. Design frameworks for fixed layout may need to include coding for multiple display devices.
Hybrid design maintains most static content control, but is adapted to textual publishing, and for readers, to conventional (printed) display. Hybrid layouts are generally easy on the eye and are found on most sites that distribute traditional images and text to readers. For some sites, hybrid design makes an otherwise cold text column appear warm and balanced. A good example of hybrid layout is Wordpress, where liquid design is now optional, and movie and auditory media is stretching the envelope.
Fluid design is useful where content is delivered to an 'unknown device' population. Appropriate liquid code displays images, text and spaces proportional to display size. Someone with a handheld can see view and interact with the same content as someone using a large desktop monitor. Fluid display is the future for most layout projects, but let's consider obstacles to this current direction.
A note here on space and layout is important. As W3C conventions evolve, the use of design "space" is becoming less static and more fluid in its potential. The result is that old layouts look ... old. In dealing with font layout, even expressed as ems, a static core cannot be escaped and often anchors most page content. However, as new standards are adopted by device manufacturers, viewers notice a wider spectrum of content and a greater interaction between and through content. For the World Wide Web Consortium drawing up tomorrows layout conventions, new media types and methods are increasingly in the mix. It is a true double axiom that 'content is all about layout', and 'layout is all about content'. We could say that layout is what designers squeeze into available technology - content is the culture manifested in the layout. "Space' is the envelope holding layout and content together. Space communicates style (layout appearance) to the target population. Understanding how to adapt space to this layout-content relationship is essential to web design. Every design's survivability depends on its sensitivity to emerging technology (within the cultures that its framework is servicing), and immediate acceptance depends on the layout or presentation of that content. On every page, no content is more susceptible to changes and variations in standards, than space. While the professional designer casually admits that 90% of design code is used to adapt space, most of his current work deploys spatial manipulations being used to actively reshape Internet communication.
Conceptual barriers to adequate layout abound! Presently layout is challenged by conflicting convention that makes it impossible to fit liquid and hybrid layout to the bottom corners of a display. Simply put, display device manufactures use the top right and/or left corners to display content. For non-standard equipment, setting custom fixed layout to their device is still seen by some businesses as a means of increasing revenue, as they can sell a 'unique' display. This business approach, domainating the digital market at the end of the last century, is not so useful today. However, some would claim a decade behind schedule, CSS3 and HTML5 are finally taking the four penultimate display reference point seriously. Just in time for 3 dimensional vector layout to tangle designers' templates in conundrums!
A common misconception among designers is to assume their layout is liquid because initial space and text container widths are in percents. However, their 'liquid' framework, while adhering to focused conventions, failed to manage graphic content. A subsequent edit placing a large image on the page, destroys the page appearance. When managing a design framework, it is critical that layout address content, convention and user interaction.

Device
On the web the designer has no control over several factors, including the size of the browser window, the web browser used, the input devices used (operating system, mouse, touch screen, voice command, text, teletype, cell phone, or other hand-held), and the size, design, and other characteristics of the fonts that users have available (installed) and enabled (preference) on their device. Unique manufacture and conflicting device contentions are further complicated by varying browser interpretations of the same content, and some content automatically can trigger browser changes. Web designers do well to study and become proficient at removing competitive device and software markup so that web pages display as they are coded to display. Eric Meyers, a well known educator and developer, is one of many resources who have spear-headed HTML reset coding. While they cannot yet leave one local environment to control another, web designers can adjust target environments to remove much common markup that alters or corrupts their web content. Because device manufacturers are highly protective of their patent markup, Meyers and others caution that reset remains experimental.

Tableless Web design
Tableless web design
When Netscape Navigator 4 dominated the browser market, the popular solution available for designers to lay out a Web page was by using tables. Often even simple designs for a page would require dozens of tables nested in each other. Many web templates in Dreamweaver and other WYSIWYG editors still use this technique today. Navigator 4 didn't support CSS to a useful degree, so it simply wasn't used.
After the browser wars subsided, and the dominant browsers such as Internet Explorer became more W3C compliant, designers started turning toward CSS as an alternate means of laying out their pages. CSS proponents say that tables should be used only for tabular data, not for layout. Using CSS instead of tables also returns HTML to a semantic markup, which helps bots and search engines understand what's going on in a web page. All modern Web browsers support CSS with different degrees of limitations.
However, one of the main points against CSS is that by relying on it exclusively, control is essentially relinquished as each browser has its own quirks which result in a slightly different page display. This is especially a problem as not every browser supports the same subset of CSS rules. There are the means to apply different styles depending on which browser and version are used but incorporating these exceptions makes maintaining the style sheets more difficult as there are styles in more than one place to update.
For designers who are used to table-based layouts, developing Web sites in CSS often becomes a matter of trying to replicate what can be done with tables, leading some to find CSS design rather cumbersome due to lack of familiarity. For example, at one time it was rather difficult to produce certain design elements, such as vertical positioning, and full-length footers in a design using absolute positions. With the abundance of CSS resources available online today, though, designing with reasonable adherence to standards involves little more than applying CSS 2.1 or CSS 3 to properly structured markup.
These days most modern browsers have solved most of these quirks in CSS rendering and this has made many different CSS layouts possible. However, some people continue to use old browsers, and designers need to keep this in mind, and allow for graceful degrading of pages in older browsers. Most notable among these old browsers is Internet Explorer 6, which, according to some web designers,[who?] is becoming the new Netscape Navigator 4 — a block that holds the World Wide Web back from converting to CSS design. However, the W3 Consortium has made CSS in combination with XHTML the standard for web design.

Pathology

2009-08-13T04:29:00.000-07:00

Pathology (from Greek πάθος, pathos, "fate, harm"; and -λογία, -logia) is the study and diagnosis of disease through examination of organs, tissues, bodily fluids, and whole bodies (autopsies). The term also encompasses the related scientific study of disease processes, called General pathology.
Medical pathology is divided in two main branches, Anatomical pathology and Clinical pathology. Veterinary pathology is concerned with animal disease whereas Phytopathology is the study of plant diseases.
Contents:
1 History of pathology
2 General pathology
3 Pathology as a medical specialty
3.1 Anatomical pathology
3.2 Clinical pathology
4 Forensic pathology
5 Veterinary pathology
6 Plant pathology
7 Molecular pathology
8 See also
9 References
10 External links

History of pathology
The history of pathology can be traced to the earliest application of the scientific method to the field of medicine, a development which occurred in the Middle East during the Islamic Golden Age and in Western Europe during the Italian Renaissance.
Early systematic human dissections were carried out by the Ancient Greek physicians Herophilus of Chalcedon and Erasistratus of Chios in the early part of the third century BC.[1] The first physician known to have made postmortem dissections was the Arabian physician Avenzoar (1091–1161). Rudolf Virchow (1821–1902) is generally recognized to be the father of microscopic pathology. Most early pathologists were also practicing physicians or surgeons.

General pathology
General pathology, also called investigative pathology, experimental pathology or theoretical pathology,[citation needed] is a broad and complex scientific field which seeks to understand the mechanisms of injury to cells and tissues, as well as the body's means of responding to and repairing injury. Areas of study include cellular adaptation to injury, necrosis, inflammation, wound healing and neoplasia. It forms the foundation of pathology, the application of this knowledge to diagnose diseases in humans and animals.
The term "general pathology" is also used to describe the practice of both anatomical and clinical pathology.

Pathology as a medical specialty
Pathologists are physicians who diagnose and characterize disease in living patients by examining biopsies or bodily fluid. The vast majority of cancer diagnoses are made or confirmed by a pathologist. Pathologists may also conduct autopsies to investigate causes of death. Pathology is a core discipline of medical school and many pathologists are also teachers. As managers of medical laboratories, pathologists play an important role in the development of Laboratory information systems. Although the medical practice of pathology grew out of the tradition of investigative pathology, most modern pathologists do not perform original research.
Pathology is a unique medical specialty in that pathologists typically do not see patients directly, but rather serve as consultants to other physicians (often referred to as "clinicians" within the pathology community). To be licensed, candidates must complete medical training, an approved residency program and be certified by an appropriate body. In the US, certification is by the American Board of Pathology. The organization of subspecialties within pathology varies between nations, but usually includes anatomical pathology and clinical pathology.

Anatomical pathology
Anatomical pathology (Commonwealth) or Anatomic pathology (U.S.) is a medical specialty that is concerned with the diagnosis of disease based on the gross, microscopic, chemical, immunologic and molecular examination of organs, tissues, and whole bodies (autopsy).
Anatomical pathology is itself divided in subspecialties, the main ones being surgical pathology, cytopathology and forensic pathology. To be licensed to practice pathology, one has to complete medical school and secure a license to practice medicine. An approved residency program and certification (in the U.S., the American board of Pathology) is usually required to obtain employment or hospital privileges.
Anatomical pathology is one of two branches of pathology, the other being clinical pathology, the diagnosis of disease through the laboratory analysis of bodily fluids and/or tissues. Often, pathologists practice both anatomical and clinical pathology, a combination known as general pathology. The distinction between anatomic and clinical pathology is increasingly blurred by the introduction of technologies that require new expertise and the need to provide patients and referring physicians with integrated diagnostic reports. Similar specialties exist in veterinary pathology.

Clinical pathology
Clinical pathology or Biomedical Science (UK), is a medical specialty that is concerned with the diagnosis of disease based on the laboratory analysis of bodily fluids such as blood and urine, and tissues using the tools of chemistry, microbiology, hematology and molecular pathology. Clinical pathologists work in close collaboration with medical technologists hospital administrations and referring physicians to insure the accuracy and optimal utilization of laboratory testing.
Clinical pathology is one of the two major divisions of pathology, the other being anatomical pathology. Often, pathologists practice both anatomical and clinical pathology, a combination sometimes known as general pathology.

Forensic pathology
Forensic pathology is a branch of pathology concerned with determining the cause of death by examination of a cadaver. The autopsy is performed by the pathologist at the request of a coroner usually during the investigation of criminal law cases and civil law cases in some jurisdictions. Forensic pathologists are also frequently asked to confirm the identity of a cadaver.
Forensic pathology is that branch of medicine,which deals with the study of cause of death by examination of a dead body at the request of a coroner during legal cases.
The word forensics is derived from the Latin forēnsis meaning forum.

Veterinary pathology and veterinary pathologist
Veterinary pathologists are doctors of veterinary medicine who specialise in the diagnosis of diseases through the examination of animal tissue and body fluids. Like for medical pathology, veterinary pathology is divided in two branches, anatomical pathology and clinical pathology. Veterinary pathologists are critical participants in the drug development process.

Phytopathology
Plant pathology (also phytopathology) is the scientific study of plant diseases caused by pathogens (infectious diseases) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are insects, mites, vertebrate or other pests that affect plant health by consumption of plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.
The "Disease triangle" is a central concept of plant pathology. It is based on the principle that infectious diseases develop, or do not develop, based on three-way interactions between the host, the pathogen and environmental conditions.

Molecular pathology
Molecular pathology is an emerging discipline within pathology which is focused in the study and diagnosis of disease through the examination of molecules within organs, tissues or bodily fluids. Molecular pathology shares some aspects of practice with both anatomic pathology and clinical pathology, molecular biology, biochemistry, proteomics and genetics, and is sometimes considered a "crossover" discipline. It is multi-disciplinary in nature and focuses mainly on the sub-microscopic aspects of disease.
It is a scientific discipline that encompasses the development of molecular and genetic approaches to the diagnosis and classification of human tumours, the design and validation of predictive biomarkers for treatment response and disease progression, the susceptibility of individuals of different genetic constitution to develop cancer and the environmental and lifestyle factors implicated in carcinogenesis.

See also
Surgical pathology
Hematopathology
Medical laboratory
Important publications in pathology
List of pathologists

Personal computer hardware

2009-08-09T20:02:00.000-07:00

Your PC (Personal Computer) is a system, consisting of many components. Some of those components, like Windows XP, and all your other programs, are software. The stuff you can actually see and touch, and would likely break if you threw it out a fifth-story window, is hardware.

Not everybody has exactly the same hardware. But those of you who have a desktop system, like the example shown in Figure 1, probably have most of the components shown in that same figure. Those of you with notebook computers probably have most of the same components. Only in your case the components are all integrated into a single book-sized portable unit.

Figure 1

The system unit is the actual computer; everything else is called a peripheral device. Your computer's system unit probably has at least one floppy disk drive, and one CD or DVD drive, into which you can insert floppy disks and CDs. There's another disk drive, called the hard disk inside the system unit, as shown in Figure 2. You can't remove that disk, or even see it. But it's there. And everything that's currently "in your computer" is actually stored on that hard disk. (We know this because there is no place else inside the computer where you can store information!).

Figure 2

The floppy drive and CD drive are often referred to as drives with removable media or removable drives for short, because you can remove whatever disk is currently in the drive, and replace it with another. Your computer's hard disk can store as much information as tens of thousands of floppy disks, so don't worry about running out of space on your hard disk any time soon. As a rule, you want to store everything you create or download on your hard disk. Use the floppy disks and CDs to send copies of files through the mail, or to make backup copies of important items.

Random Access Memory (RAM)
There's too much "stuff" on your computer's hard disk to use it all at the same time. During the average session sitting at the computer, you'll probably use only a small amount of all that's available. The stuff you're working with at any given moment is stored in random access memory (often abbreviated RAM, and often called simply "memory"). The advantage using RAM to store whatever you're working on at the moment is that RAM is very fast. Much faster than any disk. For you, "fast" translates to less time waiting and more time being productive. So if RAM is so fast, why not put everything in it? Why have a hard disk at all? The answer to that lies in the fact that RAM is volatile. As soon as the computer is shut off, whether intentionally or by an accidental power outage, every thing in RAM disappears, just as quickly as a light bulb goes out when the plug is pulled. So you don't want to rely on RAM to hold everything. A disk, on the other hand, holds its information whether the power is on or off.

The Hard Disk
All of the information that's "in your computer", so to speak, is stored on your computer's hard disk. You never see that actual hard disk because it's sealed inside a special housing and needs to stay that way. Unlike RAM, which is volatile, the hard disk can hold information forever -- with or without electricity. Most modern hard disks have tens of billions of bytes of storage space on them. Which, in English, means that you can create, save, and download files for months or years without using up all the storage space it provides.
In the unlikely event that you do manage to fill up your hard disk, Windows will start showing a little message on the screen that reads "You are running low on disk space" well in advance of any problems. In fact, if that message appears, it won't until you're down to about 800 MB of free space. And 800 MB of empty space is equal to about 600 blank floppy disks. That's still plenty of room!

The Mouse
Obviously you know how to use your mouse, since you must have used it to get here. But let's take a look at the facts and buzzwords anyway. Your mouse probably has at least two buttons on it. The button on the left is called the primary mouse button, the button on the right is called the secondary mouse button or just the right mouse button. I'll just refer to them as the left and right mouse buttons. Many mice have a small wheel between the two mouse buttons, as illustrated in Figure 3.

Figure 3

The idea is to rest your hand comfortably on the mouse, with your index finger touching (but not pressing on) the left mouse button. Then, as you move the mouse, the mouse pointer (the little arrow on the screen) moves in the same direction. When moving the mouse, try to keep the buttons aimed toward the monitor -- don't "twist" the mouse as that just makes it all the harder to control the position of the mouse pointer.
If you find yourself reaching too far to get the mouse pointer where you want it to be on the screen, just pick up the mouse, move it to where it's comfortable to hold it, and place it back down on the mousepad or desk. The buzzwords that describe how you use the mouse are as follows:

Point: To point to an item means to move the mouse pointer so that it's touching the item.
Click: Point to the item, then tap (press and release) the left mouse button.
Double-click: Point to the item, and tap the left mouse button twice in rapid succession - click-click as fast as you can.
Right-click: Point to the item, then tap the mouse button on the right.
Drag: Point to an item, then hold down the left mouse button as you move the mouse. To drop the item, release the left mouse button.
Right-drag: Point to an item, then hold down the right mouse button as you move the mouse. To drop the item, release the right mouse button.

The Keyboard
Like the mouse, the keyboard is a means of interacting with your computer. You really only need to use the keyboard when you're typing text. Most of the keys on the keyboard are laid out like the keys on a typewriter. But there are some special keys like Esc (Escape), Ctrl (Control), and Alt (Alternate). There are also some keys across the top of the keyboard labeled F1, F2, F3, and so forth. Those are called the function keys, and the exact role they play depends on which program you happen to be using at the moment.
Most keyboards also have a numeric keypad with the keys laid out like the keys on a typical adding machine. If you're accustomed to using an adding machine, you might want to use the numeric keypad, rather than the numbers across the top of the keyboard, to type numbers. It doesn't really matter which keys you use. The numeric keypad is just there as a convenience to people who are accustomed to adding machines.

Figure 4

Most keyboards also contain a set of navigation keys. You can use the navigation keys to move around around through text on the screen. The navigation keys won't move the mouse pointer. Only the mouse moves the mouse pointer.
On smaller keyboards where space is limited, such as on a notebook computer, the navigation keys and numeric keypad might be one in the same. There will be a Num Lock key on the keypad. When the Num Lock key is "on", the numeric keypad keys type numbers. When the Num Lock key is "off", the navigation keys come into play. The Num Lock key acts as a toggle. Which is to say, when you tap it, it switches to the opposite state. For example, if Num Lock is on, tapping that key turns it off. If Num Lock is off, tapping that key turns Num Lock on.

Combination Keystrokes (Shortcut keys)
Those mysterious Ctrl and Alt keys are often used in combination with other keys to perform some task. We often refer to these combination keystrokes as shortcut keys, because they provide an alternative to using the mouse to select menu options in programs. Shortcut keys are always expressed as:
key1+key2
where the idea is to hold down key1, tap key2, then release key1. For example, to press Ctrl+Esc hold down the Ctrl key (usually with your pinkie), tap the Esc key, then release the Ctrl key. To press Alt+F you hold down the Alt key, tap the letter F, then release the Alt key.

Environmental Engineering Science

2009-08-03T21:32:00.000-07:00

Environmental Engineering Science (EES) is a multidisciplinary field of engineering science that combines the biological, chemical and physical sciences with the field of engineering. This major traditionally requires the student to take many basic engineering classes in fields such as thermodynamics, advanced math, computer modeling and simulation as well as technical classes in subjects such as statics, mechanics, hydrology, and fluid dynamics. As the student progresses, the upper division elective classes define a specific field of study for the student with a choice in a wide range of science, technology and engineering related classes.

As a recently created program, environmental engineering science has not yet been incorporated into the terminology found among environmentally focused professionals . It should be noted in the few engineering colleges that offer this major, the curriculum shares more classes in common with environmental engineering than it does with environmental science. Typically, EES students follow a similar course curriculum with environmental engineers until their fields diverge during the last year of college. While, a majority of the environmental engineering students must take classes designed to connect their knowledge of the environment to modern building materials and construction methods. This is meant to steer the environmental engineer into a field where they will more than likely assist in building treatment facilities, preparing environmental impact reports or helping to mitigate air pollution from specific point sources.
Meanwhile, the environmental engineering science student will choose a direction for their career. From the wide range of electives they have to choose from, these students can move into a wide range of fields in anything from the design of nuclear storage facilities, bacterial bioreactors or environmental policies. With this in mind, it is important to note that these students combine the practical design background of an engineer with the detailed theory found in many of the biological and physical sciences. In other words, these students have the capabilities to imagine, design and build ideas from many interconnected disciplines concerned with the healthy fate of our environment.

Description at Two Well Known Engineering Institutions

UC Berkeley
The College of Engineering at UC Berkeley defines Environmental Engineering Science as followsThis is a multidisciplinary field requiring an integration of physical, chemical and biological principles with engineering analysis for environmental protection and restoration. The program incorporates courses from many departments on campus to create a discipline that is rigorously based in science and engineering, while addressing a wide variety of environmental issues. Although an environmental engineering option exists within the civil engineering major, the engineering science curriculum provides a more broadly based foundation in the sciences than is possible in civil engineering. This major prepares the student for a career or graduate study in many environmental areas.

Massachusetts Institute of Technology
At MIT, the major is described in their curriculum and says
The Bachelor of Science in Environmental Engineering Science emphasizes the fundamental physical, chemical, and biological processes necessary for understanding the interactions between man and the environment. Issues considered include the provision of clean and reliable water supplies, flood forecasting and protection, development of renewable and nonrenewable energy sources, causes and implications of climate change, and the impact of human activities on natural cycles. Both programs provide awareness of the sociopolitical context in which civil and environmental engineering problems are solved. Premedical students may satisfy medical school entrance requirements while earning the accredited degree in environmental engineering science with proper planning of their program.

Environmental Science

2009-07-29T03:37:00.000-07:00

Environmental science is an expression encompassing the wide range of scientific disciplines that need to be brought together to understand and manage earth systems and the many interactions among physical, chemical, and biological components. Environmental Science provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems.[1] Individuals may operate as Environmental scientists or a group of scientists may work together pooling their individual skills. The most common model for the delivery of Environmental science is through the work of an individual scientist or small team drawing on the peer-reviewed, published work of many other scientists throughout the world.

The role of environmental science
Environmental Scientists work to understand how the environment functions and how human actions (anthropogenic effects) affect environmental processes. Often these environmental processes are in the setting of terrestrial and aquatic ecosystems as this is where the impact on organisms is most often noticed. In addition, environmental scientists help planners develop and construct buildings, transportation corridors, and utilities that protect water resources and reflect efficient and beneficial land use. Due to the interdisciplinary nature of environmental science, teams of professionals commonly work together to conduct environmental research or to produce Environmental Impact Statements. Other professional organizations engender work in environmental science and aid in communication among the diverse sciences.
Since most environmental issues deal with human activities, study of economics, law and social sciences are often applied in conjunction with environmental science.
Environmental science encompasses issues such as climate change, conservation, biodiversity, water quality, groundwater contamination , soil contamination, use of natural resources, waste management, sustainable development, disaster reduction, and air pollution.
While the environment has been studied for at least as long as there has been science, the recent interest in putting the pieces of understanding together to study environmental systems has come alive as a substantive, active field of scientific investigation starting in the 1960s and 1970s. This has been driven by the need for a large multi-disciplined team to analyze complex environmental problems, the arrival of substantive environmental laws requiring specific environmental protocols of investigation, and growing public awareness of a need for action in addressing environmental problems.

Components
Atmospheric sciences examine the phenomenology of the Earth's gaseous outer layer with emphasis upon interrelation to other systems. Atmospheric sciences comprises meteorological studies, greenhouse gas phenomena, atmospheric dispersion modeling of airborne contaminants, sound propagation phenomena related to noise pollution, and even light pollution
Taking the example of the global warming phenomena, physicists create computer models of atmospheric circulation and infra-red radiation transmission, chemists examine the inventory of atmospheric chemicals and their reactions, biologists analyze the plant and animal contributions to carbon dioxide fluxes, and specialists such as meteorologists and oceanographers add additional breadth in understanding the atmospheric dynamics.
Ecology studies typically analyse the dynamics of biological populations and some aspect of their environment. These studies might address endangered species, predator/prey interactions, habitat integrity, effects upon populations by environmental contaminants, or impact analysis of proposed land development upon species viability.
An interdisciplinary analysis of an ecological system which is being impacted by one or more stressors might include several related environmental science fields. For example one might examine an estuarine setting where a proposed industrial development could impact certain species by water pollution and air pollution. For this study biologists would describe the flora and fauna, chemists would analyze the transport of water pollutants to the marsh, physicists would calculate air pollution emissions and geologists would assist in understanding the marsh soils and bay muds.
Environmental chemistry is the study of chemical alterations in the environment. Principal areas of study include soil contamination and water pollution. The topics of analysis involve chemical degradation in the environment, multi-phase transport of chemicals (for example, evaporation of a solvent containing lake to yield solvent as an air pollutant), and chemical effects upon biota.
As an example study, consider the case of a leaking solvent tank which has entered the soil upgradient of a habitat of an endangered species of amphibian. As a method to resolve or to understand the extent of soil contamination, and subsurface transport of solvent, a computer model would be implemented. Chemists would then characterize the type(s) of molecular bonding of the solvent to the specific soil type and biologists would study the impacts upon soil arthropods, plants and ultimately pond dwelling copepods who are the food of the endangered amphibian.
Geosciences includes environmental geology, environmental soil science, volcanic phenomena and evolution of the Earth's crust. In some classification systems it can also embrace hydrology including oceanography.
As an example study of soils erosion, calculations would be made of surface runoff by soil scientists. Hydrologists would assist in examining sediment transport in overland flow. Physicists would contribute by assessing the changes in light transmission in the receiving waters. Biologists would analyze subsequent impacts to aquatic flora and fauna from increases in water turbidity.

Regulations driving the studies
In the U.S. the National Environmental Policy Act (NEPA) of 1969 set forth requirements for analysis of major projects in terms of specific environmental criteria. Numerous state laws have echoed these mandates, applying the principles to local scale actions. The upshot has been an explosion of documentation and study of environmental consequences before the fact of development actions.
One can examine the specifics of environmental science by reading examples of Environmental Impact Statements prepared under NEPA such as: Wastewater treatment expansion options discharging into the San Diego/Tiajuana Estuary, Expansion of the San Francisco International Airport, Development of the Houston, Metro Transportation system, Expansion of the metropolitan Boston MBTA transit system, and Construction of Interstate 66 through Arlington, Virginia.
In England and Wales the Environment Agency (EA), formed in 1996 is a public body for protecting and improving the environment and enforces the regulations listed on the communities and local government site. (formerly the office of the deputy prime minister). The Agency was set up under the Environment Act 1995 as an independent body and works closely with UK Government to enforce the regulations.

Terminology
In common usage, "environmental science" and "ecology" are often used interchangeably, but technically, ecology refers only to the study of organisms and their interactions with each other and their environment. Ecology could be considered a subset of environmental science, which also could involve purely chemical, or public health issues (for example) ecologists would be unlikely to study. In practice, there is considerable overlap between the work of ecologists and other environmental scientists.

See also
Actinides in the environment
American Geophysical Union
Association of Environmental Professionals
Atmospheric dispersion modeling
Biogeochemistry
Ecogenetics
Ecological sanitation
Environmental chemistry
Environmental Engineering Science
Environmental Impact Statement
Environmental monitoring
Environmental planning
Environmental studies
Earth Summit
Freshwater environmental quality parameters
Glossary of environmental science
Lists of environmental topics
Phase I Environmental Site Assessment

References
^ Environmental Science: Iowa State University
^ environmental scientists and hydrologists
^ Beychok, M.R. (2005). Fundamentals Of Stack Gas Dispersion (4th Edition ed.). author-published. ISBN 0-9644588-0-2. www.air-dispersion.com
^ Turner, D.B. (1994). Workbook of atmospheric dispersion estimates: an introduction to dispersion modeling (2nd Edition ed.). CRC Press. ISBN 1-56670-023-X. www.crcpress.com
^ http://www.environment-agency.gov.uk/
^ http://www.communities.gov.uk/index.asp?id=1503251

External links
Environmental Protection Agency of the United States
Environmental Science Program, Iowa State University
Glossary of environmental terms
Institute for Environmental Physics - University of Bremen
School of Environment and Natural Resources, The Ohio State University

Types of Computer

2009-07-22T21:11:00.000-07:00

Workstation

A workstation is a high-end personal computer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems.

Desktop computer

Prior to the wide spread of PCs a computer that could fit on a desk was considered remarkably small. Today the phrase usually indicates a particular style of computer case. Desktop computers come in a variety of styles ranging from large vertical tower cases to small form factor models that can be tucked behind an LCD monitor. In this sense, the term 'desktop' refers specifically to a horizontally-oriented case, usually intended to have the display screen placed on top to save space on the desk top. Most modern desktop computers have separate screens and keyboards.

Single unit
Single unit PCs (also known as all-in-one PCs) are a subtype of desktop computers, which combine the monitor and case of the computer within a single unit. The monitor almost always utilizes a touchscreen as an optional method of user input, however detached keyboards and mice are normally still included. The inner components of the PC are often located directly behind the monitor.

Nettop
A subtype of desktops, called nettops, was introduced by Intel in February 2008 to describe low-cost, lean-function, desktop computers. A similar subtype of laptops (or notebooks) are the netbooks (see below).

Laptop

A laptop computer or simply laptop, also called a notebook computer or sometimes a notebook,

is a small personal computer designed for mobility. Usually all of the interface hardware needed to operate the laptop, such as parallel and serial ports, graphics card, sound channel, etc., are built in to a single unit. Most laptops contain batteries to facilitate operation without a readily available electrical outlet. In the interest of saving power, weight and space, they usually share RAM with the video channel, slowing their performance compared to an equivalent desktop machine.
One main drawback of the laptop is that, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Some devices can be attached externally through ports (including via USB), however internal upgrades are not recommended or in some cases impossible, making the desktop PC more modular.
A subtype of notebooks, called subnotebooks, are computers with most of the features of a standard laptop computer but smaller. They are larger than hand-held computers, and usually run full versions of desktop/laptop operating systems. Ultra-Mobile PCs (UMPC) are usually considered subnotebooks, or more specifically, subnotebook Tablet PCs (see below). Netbooks are sometimes considered in this category, though they are sometimes separated in a category of their own (see below).
Desktop replacements, meanwhile, are large laptops meant to replace a desktop computer while keeping the mobility of a laptop.

Netbook
Netbooks are small portable computers in a "clamshell" design, that are designed specifically for wireless communication and access to the Internet. They are generally much lighter and cheaper than subnotebooks, and have a smaller display, between 7" and 9", with a screen resolution between 800x600 and 1024x768 but newer models feature higher resolution at up to 1280x768 like the Gigabyte M912X netbook. The operating systems and applications on them are usually specially modified so they can be comfortably used with a smaller sized screen, and the OS was in the start Linux, although most netbooks run one of the NT version, Windows XP or Windows Vista (For example Sony's Tablet Netbook). Some netbooks make use of their built in high speed Wireless connectivity to offload some of their applications software to Internet servers, through the principle of Cloud computing, as most have small solid state storage systems instead of hard-disks. Storage capacities were usually in the 4 to 16 GB range but have largely increased expanding up to 160GB for example the Gigabyte M912X and the MSI WInd U100 with units that have hard drives instead of solid state drives. One of the first examples of such a system was the original Eee PC.

Tablet PC
HP Compaq tablet PC with rotating/removable keyboard.
A tablet PC is a notebook or slate-shaped mobile computer, first introduced by Pen computing in the early 90s with their PenGo Tablet Computer and popularized by Microsoft. Its touchscreen or graphics tablet/screen hybrid technology allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse. The form factor offers a more mobile way to interact with a computer. Tablet PCs are often used where normal notebooks are impractical or unwieldy, or do not provide the needed functionality.

Samsung Q1 Ultra-Mobile PC.
The ultra-mobile PC (UMPC) is a specification for a small form factor. It was developed as a joint development exercise by Microsoft, Intel, and Samsung, among others. Current UMPCs typically feature the Windows XP, Windows Vista, Windows 7, or Linux operating system and low-voltage Intel Atom or VIA C7-M processors.

Home theater PC
Antec Fusion V2 home theater PC with keyboard on top.
A home theater PC (HTPC) is a convergence device that combines the functions of a personal computer and a digital video recorder. It is connected to a television or a television-sized computer display and is often used as a digital photo, music, video player, TV receiver and digital video recorder. Home theater PCs are also referred to as media center systems or media servers. The general goal in a HTPC is usually to combine many or all components of a home theater setup into one box. They can be purchased pre-configured with the required hardware and software needed to add television programming to the PC, or can be cobbled together out of discrete components as is commonly done with MythTV, Windows Media Center, GB-PVR, SageTV, Famulent or LinuxMCE.

An O2 pocket PC
A pocket PC is a hardware specification for a handheld-sized computer (personal digital assistant) that runs the Microsoft Windows Mobile operating system. It may have the capability to run an alternative operating system like NetBSD or Linux. It has many of the capabilities of modern desktop PCs.
Currently there are tens of thousands of applications for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware. Some of these devices also include mobile phone features. Microsoft compliant Pocket PCs can also be used with many other add-ons like GPS receivers, barcode readers, RFID readers, and cameras. In 2007, with the release of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of a new naming scheme. Devices without an integrated phone are called Windows Mobile Classic instead of Pocket PC. Devices with an integrated phone and a touch screen are called Windows Mobile Professional.

Computer

2009-07-19T03:46:00.000-07:00

A personal computer (PC) is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator.

A personal computer may be a desktop computer, a laptop computer or a tablet computer. The most common current operating systems for personal computers are Microsoft Windows, Mac OS X and Linux, while the most common microprocessors are x86-compatible CPUs, ARM architecture CPUs and PowerPC CPUs. Software applications for personal computers include word processing, spreadsheets, databases, Web browsers and e-mail clients, games, and myriad personal productivity and special-purpose software. Modern personal computers often have high-speed or dial-up connections to the Internet, allowing access to the World Wide Web and a wide range of other resources.

A PC may be used at home, or may be found in an office, often connected to a local area network (LAN). This is in contrast to the batch processing or time-sharing models which allowed large expensive systems to be used by many people, usually at the same time, or large data processing systems which required a full-time staff to operate efficiently.

While early PC owners usually had to write their own programs to do anything useful with the machines, today's users have access to a wide range of commercial and non-commercial software which is provided in ready-to-run form. Since the 1980s, Microsoft and Intel have been dominating much of the personal computer market with the Wintel platform.

The capabilities of the personal computer have changed greatly since the introduction of electronic computers. By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person. The introduction of the microprocessor, a single chip with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after about 1975. Early personal computers - generally called microcomputers - were sold often in Electronic kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done by toggle switches, and output was provided by front panel indicators. Practical use required peripherals such as keyboards, computer terminals, disk drives, and printers. Micral N was the earliest commercial, non-kit "personal" computer based on a microprocessor, the Intel 8008. It was built starting in 1972 and about 90,000 units were sold. Unlike other hobbyist computers of its day, which were sold as kits, in 1976 Steve Jobs and Steve Wozniak sold the Apple I, which was a fully assembled circuit board containing about 30 chips. In 1977, Apple Computers introduced the Apple II as the world’s first personal computer; by then, mass-market pre-assembled computers allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware.

Throughout the late 1970s and into the 1980s, computers were developed for household use, offering personal productivity, programming and games. Somewhat larger and more expensive systems (although still low-cost compared with minicomputers and mainframes) were aimed for office and small business use. Workstations are characterized by high-performance processors and graphics displays, with large local disk storage, networking capability, and running under a multitasking operating system. Workstations are still used for tasks such as computer-aided design, drafting and modelling, computation-intensive scientific and engineering calculations, image processing, architectural modelling, and computer graphics for animation and motion picture visual effects.

Eventually due to the IBM-PC's influence on the Personal Computer market Personal Computers and Home Computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of a few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of the personal computers used at home.

Market and sales

Personal computers worldwide in million distinguished by developed and developing worldIn 2001 125 million personal computers were shipped in comparison to 48 thousand in 1977. More than 500 million personal computers were in use in 2002 and one billion personal computers had been sold worldwide since mid-1970s until this time. Of the latter figure, 75 percent were professional or work related, while the rest sold for personal or home use. About 81.5 percent of personal computers shipped had been desktop computers, 16.4 percent laptops and 2.1 percent servers. United States had received 38.8 percent (394 million) of the computers shipped, Europe 25 percent and 11.7 percent had gone to Asia-Pacific region, the fastest-growing market as of 2002. The second billion was expected to be sold by 2008. Almost half of all the households in Western Europe had a personal computer and a computer could be found in 40 percent of homes in United Kingdom, compared with only 13 percent in 1985.

The global personal computer shipments were 264 million units in the year 2007, according to iSuppli[4], up 11.2 percent from 239 million in 2006.[5]. In year 2004, the global shipments was 183 million units, 11.6 percent increase over 2003.[6] In 2003, 152.6 million computers were shipped, at an estimated value of $175 billion.[7] In 2002, 136.7 million PCs were shipped, at an estimated value of $175 billion.[7] In 2000, 140.2 million personal computers were shipped, at an estimated value of $226 billion.[7] Worldwide shipments of personal computers surpassed the 100-million mark in 1999, growing to 113.5 million units from 93.3 million units in 1998.[8]. In 1999, Asia had 14.1 million units shipped.

As of June 2008, the number of personal computers in use worldwide hit one billion, while another billion is expected to be reached by 2014. Mature markets like the United States, Western Europe and Japan accounted for 58 percent of the worldwide installed PCs. The emerging markets were expected to double their installed PCs by 2013 and to take 70 percent of the second billion PCs. About 180 million computers (16 percent of the existing installed base) were expected to be replaced and 35 million to be dumped into landfill in 2008. The whole installed base grew 12 percent annually.

In the developed world, there has been a vendor tradition to keep adding functions to maintain high prices of personal computers. However, since the introduction of One Laptop per Child foundation and its low-cost XO-1 laptop, the computing industry started to pursue the price too. Although introduced only one year earlier, there were 14 million netbooks sold in 2008.[12] Besides the regular computer manufacturers, companies making especially rugged versions of computers have sprung up, offering alternatives for people operating their machines in extreme weather or environments.

Average selling price
For Microsoft Windows systems, the average selling price (ASP) showed a decline in 2008/2009, possibly due to low-cost netbooks, drawing $569 for desktop computers and $689 for laptops at U.S. retail in August 2008. In 2009, ASP had further fallen to $533 for desktops and to $602 for notebooks by January and to $540 and $560 in February.

Netbooks and nettops
The emergence of new market segment of small, energy-efficient and low-cost devices designed for access to the Internet (netbooks and nettops) could threaten established companies like Microsoft, Intel, HP or Dell, analysts said in July 2008. A market research firm International Data Corporation predicted that the category could grow from fewer than 500,000 in 2007 to 9 million in 2012 as the market for low cost and secondhand computers expands in developed economies. [15] Also, after Microsoft ceased selling consumer versions of Windows XP, it made an exception and continued to offer the operating system for netbook and nettop makers.

Computer

2009-07-15T22:55:00.000-07:00

Fields of computer science
As a discipline, computer science spans a range of topics from theoretical studies of algorithms and the limits of computation to the practical issues of implementing computing systems in hardware and software.The Computer Sciences Accreditation Board (CSAB) – which is made up of representatives of the Association for Computing Machinery (ACM), the Institute of Electrical and Electronics Engineers Computer Society, and the Association for Information Systems – identifies four areas that it considers crucial to the discipline of computer science: theory of computation, algorithms and data structures, programming methodology and languages, and computer elements and architecture. In addition to these four areas, CSAB also identifies fields such as software engineering, artificial intelligence, computer networking and communication, database systems, parallel computation, distributed computation, computer-human interaction, computer graphics, operating systems, and numerical and symbolic computation as being important areas of computer science.

Theory of computation
The study of the theory of computation is focused on answering fundamental questions about what can be computed, and what amount of resources are required to perform those computations. In an effort to answer the first question, computability theory examines which computational problems are solvable on various theoretical models of computation. The second question is addressed by computational complexity theory, which studies the time and space costs associated with different approaches to solving a computational problem.
The famous "P=NP?" problem, one of the Millennium Prize Problems,[19] is an open problem in the theory of computation.

P = NP ?
Computability theory
Computational complexity theory

Theoretical computer science
The broader field of theoretical computer science encompasses both the classical theory of computation and a wide range of other topics that focus on the more abstract, logical, and mathematical aspects of computing.
Mathematical logic
Automata theory
Number theory
Graph theory
Type theory
Category theory

Relationship with other fields
Despite its name, a significant amount of computer science does not involve the study of computers themselves. Because of this, several alternative names have been proposed. Certain departments of major universities prefer the term computing science, to emphasize precisely that difference. Danish scientist Peter Naur suggested the term datalogy, to reflect the fact that the scientific discipline revolves around data and data treatment, while not necessarily involving computers. The first scientific institution to use the term was the Department of Datalogy at the University of Copenhagen, founded in 1969, with Peter Naur being the first professor in datalogy. The term is used mainly in the Scandinavian countries. Also, in the early days of computing, a number of terms for the practitioners of the field of computing were suggested in the Communications of the ACM – turingineer, turologist, flow-charts-man, applied meta-mathematician, and applied epistemologist. Three months later in the same journal, comptologist was suggested, followed next year by hypologist.The term computics has also been suggested.Informatik was a term used in Europe with more frequency.
The renowned computer scientist Edsger Dijkstra stated, "Computer science is no more about computers than astronomy is about telescopes." The design and deployment of computers and computer systems is generally considered the province of disciplines other than computer science. For example, the study of computer hardware is usually considered part of computer engineering, while the study of commercial computer systems and their deployment is often called information technology or information systems. However, there has been much cross-fertilization of ideas between the various computer-related disciplines. Computer science research has also often crossed into other disciplines, such as cognitive science, economics, mathematics, physics (see quantum computing), and linguistics.
Computer science is considered by some to have a much closer relationship with mathematics than many scientific disciplines, with some observers saying that computing is a mathematical science. Early computer science was strongly influenced by the work of mathematicians such as Kurt Gödel and Alan Turing, and there continues to be a useful interchange of ideas between the two fields in areas such as mathematical logic, category theory, domain theory, and algebra.
The relationship between computer science and software engineering is a contentious issue, which is further muddied by disputes over what the term "software engineering" means, and how computer science is defined. David Parnas, taking a cue from the relationship between other engineering and science disciplines, has claimed that the principal focus of computer science is studying the properties of computation in general, while the principal focus of software engineering is the design of specific computations to achieve practical goals, making the two separate but complementary disciplines.
The academic, political, and funding aspects of computer science tend to depend on whether a department formed with a mathematical emphasis or with an engineering emphasis. Computer science departments with a mathematics emphasis and with a numerical orientation consider alignment computational science. Both types of departments tend to make efforts to bridge the field educationally if not across all research.

Computer science education
Some universities teach computer science as a theoretical study of computation and algorithmic reasoning. These programs often feature the theory of computation, analysis of algorithms, formal methods, concurrency theory, databases, computer graphics and systems analysis, among others. They typically also teach computer programming, but treat it as a vessel for the support of other fields of computer science rather than a central focus of high-level study.
Other colleges and universities, as well as secondary schools and vocational programs that teach computer science, emphasize the practice of advanced programming rather than the theory of algorithms and computation in their computer science curricula. Such curricula tend to focus on those skills that are important to workers entering the software industry. The practical aspects of computer programming are often referred to as software engineering. However, there is a lot of disagreement over the meaning of the term, and whether or not it is the same thing as programming.

Computer

2009-07-11T23:06:00.000-07:00

Computer science (or computing science) is the study of the theoretical foundations of information and computation, and of practical techniques for their implementation and application in computer systems.It is frequently described as the systematic study of algorithmic processes that describe and transform information; the fundamental question underlying computer science is, "What can be (efficiently) automated?"[4] Computer science has many sub-fields; some, such as computer graphics, emphasize the computation of specific results, while others, such as computational complexity theory, study the properties of computational problems. Still others focus on the challenges in implementing computations. For example, programming language theory studies approaches to describing computations, while computer programming applies specific programming languages to solve specific computational problems, and human-computer interaction focuses on the challenges in making computers and computations useful, usable, and universally accessible to people.
The general public sometimes confuses computer science with vocational areas that deal with computers (such as information technology), or think that it relates to their own experience of computers, which typically involves activities such as gaming, web-browsing, and word-processing. However, the focus of computer science is more on understanding the properties of the programs used to implement software such as games and web-browsers, and using that understanding to create new programs or improve existing ones.
History
The early foundations of what would become computer science predate the invention of the modern digital computer. Machines for calculating fixed numerical tasks, such as the abacus, have existed since antiquity. Wilhelm Schickard built the first mechanical calculator in 1623.Charles Babbage designed a difference engine in Victorian times helped by Ada Lovelace.Around 1900, punch-card machines were introduced. However, all of these machines were constrained to perform a single task, or at best some subset of all possible tasks.
During the 1940s, as newer and more powerful computing machines were developed, the term computer came to refer to the machines rather than their human predecessors. As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation in general. Computer science began to be established as a distinct academic discipline in the 1950s and early 1960s, with the creation of the first computer science departments and degree programs Since practical computers became available, many applications of computing have become distinct areas of study in their own right.
Although many initially believed it impossible that computers themselves could actually be a scientific field of study, in the late fifties it gradually became accepted among the greater academic population. It is the now well-known IBM brand that formed part of the computer science revolution during this time. IBM (short for International Business Machines) released the IBM 704 and later the IBM 709 computers, which were widely used during the exploration period of such devices. "Still, working with the IBM [computer] was frustrating...if you had misplaced as much as one letter in one instruction, the program would crash, and you would have to start the whole process over again". During the late 1950s, the computer science discipline was very much in its developmental stages, and such issues were commonplace.
Time has seen significant improvements in the usability and effectiveness of computer science technology. Modern society has seen a significant shift from computers being used solely by experts or professionals to a more widespread user base.

Computer

2009-07-08T03:36:00.000-07:00

A general purpose computer has four main components: the arithmetic and logic unit (ALU), the control unit, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by busses, often made of groups of wires.
The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) are collectively known as a central processing unit (CPU). Early CPUs were composed of many separate components but since the mid-1970s CPUs have typically been constructed on a single integrated circuit called a microprocessor.

Control unit
Main articles: CPU design and Control unit
The control unit (often called a control system or central controller) manages the computer's various components; it reads and interprets (decodes) the program instructions, transforming them into a series of control signals which activate other parts of the computer. Control systems in advanced computers may change the order of some instructions so as to improve performance.
A key component common to all CPUs is the program counter, a special memory cell (a register) that keeps track of which location in memory the next instruction is to be read from.

Diagram showing how a particular MIPS architecture instruction would be decoded by the control system.
The control system's function is as follows—note that this is a simplified description, and some of these steps may be performed concurrently or in a different order depending on the type of CPU:
Read the code for the next instruction from the cell indicated by the program counter.
Decode the numerical code for the instruction into a set of commands or signals for each of the other systems.
Increment the program counter so it points to the next instruction.
Read whatever data the instruction requires from cells in memory (or perhaps from an input device). The location of this required data is typically stored within the instruction code.
Provide the necessary data to an ALU or register.
If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.
Write the result from the ALU back to a memory location or to a register or perhaps an output device.
Jump back to step (1).
Since the program counter is (conceptually) just another set of memory cells, it can be changed by calculations done in the ALU. Adding 100 to the program counter would cause the next instruction to be read from a place 100 locations further down the program. Instructions that modify the program counter are often known as "jumps" and allow for loops (instructions that are repeated by the computer) and often conditional instruction execution (both examples of control flow).
It is noticeable that the sequence of operations that the control unit goes through to process an instruction is in itself like a short computer program—and indeed, in some more complex CPU designs, there is another yet smaller computer called a microsequencer that runs a microcode program that causes all of these events to happen.

Arithmetic/logic unit (ALU)
The ALU is capable of performing two classes of operations: arithmetic and logic.
The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc) and square roots. Some can only operate on whole numbers (integers) whilst others use floating point to represent real numbers—albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can be programmed to perform any arithmetic operation—although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other ("is 64 greater than 65?").
Logic operations involve Boolean logic: AND, OR, XOR and NOT. These can be useful both for creating complicated conditional statements and processing boolean logic.
Superscalar computers may contain multiple ALUs so that they can process several instructions at the same time. Graphics processors and computers with SIMD and MIMD features often provide ALUs that can perform arithmetic on vectors and matrices.
Magnetic core memory was the computer memory of choice throughout the 1960s, until it was replaced by semiconductor memory.
A computer's memory can be viewed as a list of cells into which numbers can be placed or read. Each cell has a numbered "address" and can store a single number. The computer can be instructed to "put the number 123 into the cell numbered 1357" or to "add the number that is in cell 1357 to the number that is in cell 2468 and put the answer into cell 1595". The information stored in memory may represent practically anything. Letters, numbers, even computer instructions can be placed into memory with equal ease. Since the CPU does not differentiate between different types of information, it is the software's responsibility to give significance to what the memory sees as nothing but a series of numbers.
In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte). Each byte is able to represent 256 different numbers (2^8 = 256); either from 0 to 255 or -128 to +127. To store larger numbers, several consecutive bytes may be used (typically, two, four or eight). When negative numbers are required, they are usually stored in two's complement notation. Other arrangements are possible, but are usually not seen outside of specialized applications or historical contexts. A computer can store any kind of information in memory if it can be represented numerically. Modern computers have billions or even trillions of bytes of memory.
The CPU contains a special set of memory cells called registers that can be read and written to much more rapidly than the main memory area. There are typically between two and one hundred registers depending on the type of CPU. Registers are used for the most frequently needed data items to avoid having to access main memory every time data is needed. As data is constantly being worked on, reducing the need to access main memory (which is often slow compared to the ALU and control units) greatly increases the computer's speed.
Computer main memory comes in two principal varieties: random access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it, but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer's initial start-up instructions. In general, the contents of RAM are erased when the power to the computer is turned off, but ROM retains its data indefinitely. In a PC, the ROM contains a specialized program called the BIOS that orchestrates loading the computer's operating system from the hard disk drive into RAM whenever the computer is turned on or reset. In embedded computers, which frequently do not have disk drives, all of the required software may be stored in ROM. Software stored in ROM is often called firmware, because it is notionally more like hardware than software. Flash memory blurs the distinction between ROM and RAM, as it retains its data when turned off but is also rewritable. It is typically much slower than conventional ROM and RAM however, so its use is restricted to applications where high speed is unnecessary.
In more sophisticated computers there may be one or more RAM cache memories which are slower than registers but faster than main memory. Generally computers with this sort of cache are designed to move frequently needed data into the cache automatically, often without the need for any intervention on the programmer's part.

Input/output (I/O)
Main article: Input/output

Hard disks are common I/O devices used with computers.
I/O is the means by which a computer exchanges information with the outside world. Devices that provide input or output to the computer are called peripherals. On a typical personal computer, peripherals include input devices like the keyboard and mouse, and output devices such as the display and printer. Hard disk drives, floppy disk drives and optical disc drives serve as both input and output devices. Computer networking is another form of I/O.
Often, I/O devices are complex computers in their own right with their own CPU and memory. A graphics processing unit might contain fifty or more tiny computers that perform the calculations necessary to display 3D graphics[citation needed]. Modern desktop computers contain many smaller computers that assist the main CPU in performing I/O.

Multitasking
Main article: Computer multitasking
While a computer may be viewed as running one gigantic program stored in its main memory, in some systems it is necessary to give the appearance of running several programs simultaneously. This is achieved by multitasking i.e. having the computer switch rapidly between running each program in turn.
One means by which this is done is with a special signal called an interrupt which can periodically cause the computer to stop executing instructions where it was and do something else instead. By remembering where it was executing prior to the interrupt, the computer can return to that task later. If several programs are running "at the same time", then the interrupt generator might be causing several hundred interrupts per second, causing a program switch each time. Since modern computers typically execute instructions several orders of magnitude faster than human perception, it may appear that many programs are running at the same time even though only one is ever executing in any given instant. This method of multitasking is sometimes termed "time-sharing" since each program is allocated a "slice" of time in turn.
Before the era of cheap computers, the principle use for multitasking was to allow many people to share the same computer.
Seemingly, multitasking would cause a computer that is switching between several programs to run more slowly — in direct proportion to the number of programs it is running. However, most programs spend much of their time waiting for slow input/output devices to complete their tasks. If a program is waiting for the user to click on the mouse or press a key on the keyboard, then it will not take a "time slice" until the event it is waiting for has occurred. This frees up time for other programs to execute so that many programs may be run at the same time without unacceptable speed loss.

Multiprocessing
Main article: Multiprocessing

Cray designed many supercomputers that used multiprocessing heavily.
Some computers are designed to distribute their work across several CPUs in a multiprocessing configuration, a technique once employed only in large and powerful machines such as supercomputers, mainframe computers and servers. Multiprocessor and multi-core (multiple CPUs on a single integrated circuit) personal and laptop computers are now widely available, and are being increasingly used in lower-end markets as a result.
Supercomputers in particular often have highly unique architectures that differ significantly from the basic stored-program architecture and from general purpose computers. They often feature thousands of CPUs, customized high-speed interconnects, and specialized computing hardware. Such designs tend to be useful only for specialized tasks due to the large scale of program organization required to successfully utilize most of the available resources at once. Supercomputers usually see usage in large-scale simulation, graphics rendering, and cryptography applications, as well as with other so-called "embarrassingly parallel" tasks.

Networking and the Internet
Main articles: Computer networking and Internet

Visualization of a portion of the routes on the Internet.
Computers have been used to coordinate information between multiple locations since the 1950s. The U.S. military's SAGE system was the first large-scale example of such a system, which led to a number of special-purpose commercial systems like Sabre.
In the 1970s, computer engineers at research institutions throughout the United States began to link their computers together using telecommunications technology. This effort was funded by ARPA (now DARPA), and the computer network that it produced was called the ARPANET. The technologies that made the Arpanet possible spread and evolved.
In time, the network spread beyond academic and military institutions and became known as the Internet. The emergence of networking involved a redefinition of the nature and boundaries of the computer. Computer operating systems and applications were modified to include the ability to define and access the resources of other computers on the network, such as peripheral devices, stored information, and the like, as extensions of the resources of an individual computer. Initially these facilities were available primarily to people working in high-tech environments, but in the 1990s the spread of applications like e-mail and the World Wide Web, combined with the development of cheap, fast networking technologies like Ethernet and ADSL saw computer networking become almost ubiquitous. In fact, the number of computers that are networked is growing phenomenally. A very large proportion of personal computers regularly connect to the Internet to communicate and receive information. "Wireless" networking, often utilizing mobile phone networks, has meant networking is becoming increasingly ubiquitous even in mobile computing environments.

Computer

2009-07-04T02:06:00.000-07:00

The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that a list of instructions (the program) can be given to the computer and it will store them and carry them out at some time in the future.
In most cases, computer instructions are simple: add one number to another, move some data from one location to another, send a message to some external device, etc. These instructions are read from the computer's memory and are generally carried out (executed) in the order they were given. However, there are usually specialized instructions to tell the computer to jump ahead or backwards to some other place in the program and to carry on executing from there. These are called "jump" instructions (or branches). Furthermore, jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on the result of some previous calculation or some external event. Many computers directly support subroutines by providing a type of jump that "remembers" the location it jumped from and another instruction to return to the instruction following that jump instruction.
Program execution might be likened to reading a book. While a person will normally read each word and line in sequence, they may at times jump back to an earlier place in the text or skip sections that are not of interest. Similarly, a computer may sometimes go back and repeat the instructions in some section of the program over and over again until some internal condition is met. This is called the flow of control within the program and it is what allows the computer to perform tasks repeatedly without human intervention.
Comparatively, a person using a pocket calculator can perform a basic arithmetic operation such as adding two numbers with just a few button presses. But to add together all of the numbers from 1 to 1,000 would take thousands of button presses and a lot of time—with a near certainty of making a mistake. On the other hand, a computer may be programmed to do this with just a few simple instructions. For example:mov #0,sum ; set sum to 0
mov #1,num ; set num to 1
loop: add num,sum ; add num to sum
add #1,num ; add 1 to num
cmp num,#1000 ; compare num to 1000
ble loop ; if num <= 1000, go back to 'loop'
halt ; end of program. stop running
Once told to run this program, the computer will perform the repetitive addition task without further human intervention. It will almost never make a mistake and a modern PC can complete the task in about a millionth of a second.
However, computers cannot "think" for themselves in the sense that they only solve problems in exactly the way they are programmed to. An intelligent human faced with the above addition task might soon realize that instead of actually adding up all the numbers one can simply use the equation

and arrive at the correct answer (500,500) with little work.In other words, a computer programmed to add up the numbers one by one as in the example above would do exactly that without regard to efficiency or alternative solutions.

Programs

A 1970s punched card containing one line from a FORTRAN program. The card reads: "Z(1) = Y + W(1)" and is labelled "PROJ039" for identification purposes.
In practical terms, a computer program may run from just a few instructions to many millions of instructions, as in a program for a word processor or a web browser. A typical modern computer can execute billions of instructions per second (gigahertz or GHz) and rarely make a mistake over many years of operation. Large computer programs consisting of several million instructions may take teams of programmers years to write, and due to the complexity of the task almost certainly contain errors.
Errors in computer programs are called "bugs". Bugs may be benign and not affect the usefulness of the program, or have only subtle effects. But in some cases they may cause the program to "hang"—become unresponsive to input such as mouse clicks or keystrokes, or to completely fail or "crash". Otherwise benign bugs may sometimes may be harnessed for malicious intent by an unscrupulous user writing an "exploit"—code designed to take advantage of a bug and disrupt a program's proper execution. Bugs are usually not the fault of the computer. Since computers merely execute the instructions they are given, bugs are nearly always the result of programmer error or an oversight made in the program's design.
In most computers, individual instructions are stored as machine code with each instruction being given a unique number (its operation code or opcode for short). The command to add two numbers together would have one opcode, the command to multiply them would have a different opcode and so on. The simplest computers are able to perform any of a handful of different instructions; the more complex computers have several hundred to choose from—each with a unique numerical code. Since the computer's memory is able to store numbers, it can also store the instruction codes. This leads to the important fact that entire programs (which are just lists of instructions) can be represented as lists of numbers and can themselves be manipulated inside the computer just as if they were numeric data. The fundamental concept of storing programs in the computer's memory alongside the data they operate on is the crux of the von Neumann, or stored program, architecture. In some cases, a computer might store some or all of its program in memory that is kept separate from the data it operates on. This is called the Harvard architecture after the Harvard Mark I computer. Modern von Neumann computers display some traits of the Harvard architecture in their designs, such as in CPU caches.
While it is possible to write computer programs as long lists of numbers (machine language) and this technique was used with many early computers, it is extremely tedious to do so in practice, especially for complicated programs. Instead, each basic instruction can be given a short name that is indicative of its function and easy to remember—a mnemonic such as ADD, SUB, MULT or JUMP. These mnemonics are collectively known as a computer's assembly language. Converting programs written in assembly language into something the computer can actually understand (machine language) is usually done by a computer program called an assembler. Machine languages and the assembly languages that represent them (collectively termed low-level programming languages) tend to be unique to a particular type of computer. For instance, an ARM architecture computer (such as may be found in a PDA or a hand-held videogame) cannot understand the machine language of an Intel Pentium or the AMD Athlon 64 computer that might be in a PC.
Though considerably easier than in machine language, writing long programs in assembly language is often difficult and error prone. Therefore, most complicated programs are written in more abstract high-level programming languages that are able to express the needs of the computer programmer more conveniently (and thereby help reduce programmer error). High level languages are usually "compiled" into machine language (or sometimes into assembly language and then into machine language) using another computer program called a compiler.[19] Since high level languages are more abstract than assembly language, it is possible to use different compilers to translate the same high level language program into the machine language of many different types of computer. This is part of the means by which software like video games may be made available for different computer architectures such as personal computers and various video game consoles.
The task of developing large software systems presents a significant intellectual challenge. Producing software with an acceptably high reliability within a predictable schedule and budget has historically been difficult; the academic and professional discipline of software engineering concentrates specifically on this problem.

Computer

2009-07-01T22:42:00.000-07:00

A computer is a machine that manipulates data according to a set of instructions.
Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century (1940–1945). These were the size of a large room, consuming as much power as several hundred modern personal computers (PCs). Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into a wristwatch, and can be powered by a watch battery. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". The embedded computers found in many devices from MP3 players to fighter aircraft and from toys to industrial robots are however the most numerous.
The ability to store and execute lists of instructions called programs makes computers extremely versatile, distinguishing them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore computers ranging from a mobile phone to a supercomputer are all able to perform the same computational tasks, given enough time and storage capacity.

History of computing

The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued to be used in that sense until the middle of the 20th century. From the end of the 19th century onwards though, the word began to take on its more familiar meaning, describing a machine that carries out computations.
The history of the modern computer begins with two separate technologies—automated calculation and programmability—but no single device can be identified as the earliest computer, partly because of the inconsistent application of that term. Examples of early mechanical calculating devices include the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150–100 BC). Hero of Alexandria (c. 10–70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when.[4] This is the essence of programmability.
The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer. It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling across a gateway causing automatic doors to open every hour,[6][7] and five robotic musicians who played music when struck by levers operated by a camshaft attached to a water wheel. The length of day and night could be re-programmed to compensate for the changing lengths of day and night throughout the year.
The Renaissance saw a re-invigoration of European mathematics and engineering. Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers, but none fit the modern definition of a computer, because they could not be programmed.
In 1801, Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a template which allowed his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.
It was the fusion of automatic calculation with programmability that produced the first recognizable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer, his analytical engine. Limited finances and Babbage's inability to resist tinkering with the design meant that the device was never completed.
In the late 1880s Herman Hollerith invented the recording of data on a machine readable medium. Prior uses of machine readable media, above, had been for control, not data. "After some initial trials with paper tape, he settled on punched cards ..." To process these punched cards he invented the tabulator, and the key punch machines. These three inventions were the foundation of the modern information processing industry. Large-scale automated data processing of punched cards was performed for the 1890 United States Census by Hollerith's company, which later became the core of IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.
During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.
Alan Turing is widely regarded to be the father of modern computer science. In 1936 Turing provided an influential formalisation of the concept of the algorithm and computation with the Turing machine. Of his role in the modern computer, Time Magazine in naming Turing one of the 100 most influential people of the 20th century, states: "The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine."
George Stibitz is internationally recognized as a father of the modern digital computer. While working at Bell Labs in November of 1937, Stibitz invented and built a relay-based calculator he dubbed the "Model K" (for "kitchen table", on which he had assembled it), which was the first to use binary circuits to perform an arithmetic operation. Later models added greater sophistication including complex arithmetic and programmability.

GAMES

2009-06-28T23:22:00.000-07:00

Game theory is a branch of applied mathematics that is used in the social sciences (most notably economics), biology, engineering, political science, international relations, computer science, and philosophy. Game theory attempts to mathematically capture behavior in strategic situations, in which an individual's success in making choices depends on the choices of others. While initially developed to analyze competitions in which one individual does better at another's expense (zero sum games), it has been expanded to treat a wide class of interactions, which are classified according to several criteria. Today, "game theory is a sort of umbrella or 'unified field' theory for the rational side of social science, where 'social' is interpreted broadly, to include human as well as non-human players (computers, animals, plants)" (Aumann 1987).
Traditional applications of game theory attempt to find equilibria in these games. In an equilibrium, each player of the game has adopted a strategy that they are unlikely to change. Many equilibrium concepts have been developed (most famously the Nash equilibrium) in an attempt to capture this idea. These equilibrium concepts are motivated differently depending on the field of application, although they often overlap or coincide. This methodology is not without criticism, and debates continue over the appropriateness of particular equilibrium concepts, the appropriateness of equilibria altogether, and the usefulness of mathematical models more generally.
Although some developments occurred before it, the field of game theory came into being with the 1944 book Theory of Games and Economic Behavior by John von Neumann and Oskar Morgenstern. This theory was developed extensively in the 1950s by many scholars. Game theory was later explicitly applied to biology in the 1970s, although similar developments go back at least as far as the 1930s. Game theory has been widely recognized as an important tool in many fields. Eight game theorists have won Nobel prizes in economics, and John Maynard Smith was awarded the Crafoord Prize for his application of game theory to biology.
Representation of games
The games studied in game theory are well-defined mathematical objects. A game consists of a set of players, a set of moves (or strategies) available to those players, and a specification of payoffs for each combination of strategies. Most cooperative games are presented in the characteristic function form, while the extensive and the normal forms are used to define noncooperative games.

Extensive form
Main article: Extensive form game

An extensive form game
The extensive form can be used to formalize games with some important order. Games here are often presented as trees (as pictured to the left). Here each vertex (or node) represents a point of choice for a player. The player is specified by a number listed by the vertex. The lines out of the vertex represent a possible action for that player. The payoffs are specified at the bottom of the tree.
In the game pictured here, there are two players. Player 1 moves first and chooses either F or U. Player 2 sees Player 1's move and then chooses A or R. Suppose that Player 1 chooses U and then Player 2 chooses A, then Player 1 gets 8 and Player 2 gets 2.
The extensive form can also capture simultaneous-move games and games with imperfect information. To represent it, either a dotted line connects different vertices to represent them as being part of the same information set (i.e., the players do not know at which point they are), or a closed line is drawn around them.

Normal form
Player 2chooses Left
Player 2chooses Right
Player 1chooses Up
4, 3
–1, –1
Player 1chooses Down
0, 0
3, 4
Normal form or payoff matrix of a 2-player, 2-strategy game
Main article: Normal-form game
The normal (or strategic form) game is usually represented by a matrix which shows the players, strategies, and payoffs (see the example to the right). More generally it can be represented by any function that associates a payoff for each player with every possible combination of actions. In the accompanying example there are two players; one chooses the row and the other chooses the column. Each player has two strategies, which are specified by the number of rows and the number of columns. The payoffs are provided in the interior. The first number is the payoff received by the row player (Player 1 in our example); the second is the payoff for the column player (Player 2 in our example). Suppose that Player 1 plays Up and that Player 2 plays Left. Then Player 1 gets a payoff of 4, and Player 2 gets 3.
When a game is presented in normal form, it is presumed that each player acts simultaneously or, at least, without knowing the actions of the other. If players have some information about the choices of other players, the game is usually presented in extensive form.

GAMES

2009-06-25T23:01:00.000-07:00

Video games
Video game
Video games are computer- or microprocessor-controlled games. Computers can create virtual tools to be used in a game between human (or simulated human) opponents, such as cards or dice, or can simulate far more elaborate worlds where mundane or fantastic things can be manipulated through gameplay.
A computer or video game uses one or more input devices, typically a button/joystick combination (on arcade games); a keyboard, mouse and/or trackball (computer games); or a controller or a motion sensitive tool. (console games). More esoteric devices such as paddle controllers have also been used for input. In computer games, the evolution of user interfaces from simple keyboard to mouse, joystick or joypad has profoundly changed the nature of game development.[citation needed]
There are many genres of video game; the first commercial video game, Pong, was a simple simulation of table tennis. As processing power increased, new genres such as adventure and action games were developed that involved a player guiding a character from a third person perspective through a series of obstacles. This "real-time" element cannot be easily reproduced by a board game which is generally limited to "turn-based" strategy; this advantage allows video games to simulate situations such as combat more realistically. Additionally, the playing of a video game does not require the same physical skill, strength and/or danger as a real-world representation of the game, and can provide either very realistic, exaggerated or impossible physics, allowing for elements of a fantastical nature, games involving physical violence, or simulations of sports. Lastly, a computer can, with varying degrees of success, simulate one or more human opponents in traditional table games such as chess, leading to simulations of such games that can be played by a single player.
In more open-ended computer simulations, also known as sandbox-style games, the game provides a virtual environment in which the player may be free to do whatever they like within the confines of this universe. Sometimes, there is a lack of goals or opposition, which has stirred some debate on whether these should be considered "games" or "toys". (Crawford specifically mentions Will Wright’s SimCity as an example of a toy.[1])

Online games
Main article: Online game
From the very earliest days of networked and timeshared computers, online games have been part of the culture. Early commercial systems such as Plato were at least as widely famous for their games as for their strictly educational value. In 1958, Tennis for Two dominated Visitor's Day and drew attention to the oscilloscope at the Brookhaven National Laboratory; during the 1980s, Xerox PARC was known mainly for Maze War, which was offered as a hands-on demo to visitors.
Modern online games are played using an Internet connection; some have dedicated client programs, while others require only a web browser. Some simpler browser games appeal to demographic groups (notably women and the middle-aged) that otherwise play very few video games.[citation needed]
The computer game is the most established of all sectors of the emergent new media landscape. The media is transformed from the traditional way of circulating in just one way to an interactive way. This is the phenomenon that is broadening around the world of videogame. It is an obvious example of the ways in which online and offline space can be seen as ‘merged’ rather than separate.[12]
Media audiences’ characteristic has been changing in consequence of the social changes and development. They are becoming active and interact more than ever before. The players of the game in this phenomenon are just like the social formation in our society. They are both self-regulating, creating their own social norms and subject to regulation and constraint through the code of the game and sometimes through the policing of the game by those who run it. The values that are policed vary from game to game. Many of the values encoded into game cultures reflect offline cultural values, but games also offer a chance to emphasis alternative or subjugated values in the name of fantasy and play. The players of the game at the new century are now apparently expressing their profound self through the game. When they can play with their anonymous status, they are found to be more confident to express and to step out from the position they have never been out from. It offers new experiences and pleasures based in the interactive and immersive possibilities of computer technologies.[citation needed]

Role-playing games
Main article: Role-playing game
Role-playing games, often abbreviated as RPGs, are a type of game in which the participants (usually) assume the roles of characters acting in a fictional setting. The original role playing games—or at least those explicitly marketed as such—are played with a handful of participants, usually face-to-face, and keep track of the developing fiction with pen and paper. Together, the players may collaborate on a story involving those characters; create, develop, and "explore" the setting; or vicariously experience an adventure outside the bounds of everyday life. Pen-and-paper role-playing games include, for example, Dungeons & Dragons and GURPS. Modern independent RPGs, however, often blur the line between the more traditional idea of the RPG and other traditional genres, or border on story-telling.[original research?]
The term role-playing game has also been appropriated by the video game industry to describe a genre of video games. These may be single-player games where one player experiences a programmed environment and story, or they may allow players to interact through the internet. The experience is usually quite different than traditional role-playing games. Single-player games include Final Fantasy, Fable, The Elder Scrolls, and Mass Effect. Online multi-player games, often referred to as Massively Multiplayer Online role playing games, or MMORPGs, include RuneScape, EverQuest 2, Guild Wars, MapleStory, Anarchy Online, and Dofus. As of 2008[update], the most successful MMORPG has been World of Warcraft, which controls the vast majority of the market.,[13]

Simulation
Main article: Game (simulation)
The term "game" can include simulation[14][15] or re-enactment of various activities or use in "real life" for various purposes: e.g., training, analysis, prediction. Well-known examples are war games and roleplaying. The root of this meaning may originate in the human prehistory of games deduced by anthropology from observing primitive cultures, in which children's games mimic the activities of adults to a significant degree: hunting, warring, nursing, etc. These kinds of games are preserved in modern times.

GAMES

2009-06-21T05:16:00.000-07:00

Lawn games
Lawn games are outdoor games that can be played on a lawn; an area of mown grass (or alternately, on graded soil) generally smaller than a "field" or pitch. Variations of many games that are traditionally played on a pitch are marketed as "lawn games" for home use in a front or back yard. Common lawn games include horseshoes, sholf, croquet, bocce, lawn bowls, and stake.

Tabletop games
Main article: Tabletop game
A tabletop game generally refers to any game where the elements of play are confined to a small area and which require little physical exertion, usually simply placing, picking up and moving game pieces. Most of these games are, thus, played at a table around which the players are seated and on which the game's elements are located. A variety of major game types generally fall under the heading of tabletop games. It is worth noting that many games falling into this category, particularly party games, are more free-form in their play and can involve physical activity such as mime, however the basic premise is still that the game does not require a large area in which to play it, large amounts of strength or stamina, or specialized equipment other than what comes in the box (games sometimes require additional materials like pencil and paper that are easy to procure).

Dexterity/coordination games
This class of games includes any game in which the skill element involved relates to manual dexterity or hand-eye coordination, but excludes the class of video games (see below). Games such as jacks, paper football, and Jenga require only very portable or improvised equipment and can be played on any flat level surface, while other examples, such as pinball, billiards, air hockey, foosball/table soccer, and table hockey require specialized tables or other self-contained modules on which the game is played. The advent of home video game systems largely replaced some of these, such as table hockey, however air hockey, billiards, pinball and foosball remain popular fixtures in private and public gamerooms. These games and others, as they require reflexes and coordination, are generally performed more poorly by intoxicated persons but are unlikely to result in injury because of this; as such the games are popular as drinking games. In addition, dedicated drinking games such as quarters also involve physical coordination and are popular for similar reasons.

Board games

Parcheesi is an American adaptation of a board game originating in India.
Main article: Board game
Board games use as a central tool a board on which the players' status, resources, and progress are tracked using physical tokens. Many also involve dice and/or cards. Most games that simulate war are board games (though a large number of video games have been created to simulate strategic combat; see "Video Games" below), and the board may be a map on which the players' tokens move. Virtually all board games involve "turn-based" play; one player contemplates and then makes a move, then the next player does the same, and a player can only act on their turn. This is opposed to "real-time" play as is found in some card games, most sports and most video games.
Some games, such as chess and Go, are entirely deterministic, relying only on the strategy element for their interest. Children's games, on the other hand, tend to be very luck-based, with games such as Candy Land having virtually no decisions to be made. Most other board games combine strategy and luck factors; the game of backgammon requires players to decide the best strategic move based on the roll of two dice. Trivia games have a great deal of randomness based on the questions a person gets. German-style board games are notable for often having rather less of a luck factor than many board games.
Board game groups include race games, roll-and-move games, abstract strategy games, word games, and wargames, as well as the trivia and German-style board games mentioned above. Some board games fall into multiple groups and even incorporate elements of other genres: Cranium is one popular example, where players must succeed in each of four main skills: artistry, live performance, trivia, and language skill.

GAMES

2009-06-18T01:19:00.000-07:00

Ludwig Wittgenstein
Ludwig Wittgenstein was probably the first academic philosopher to address the definition of the word game. In his Philosophical Investigations,Wittgenstein demonstrated that the elements of games, such as play, rules, and competition, all fail to adequately define what games are. He subsequently argued that the concept "game" could not be contained by any single definition, but that games must be looked at as a series of definitions that share a "family resemblance" to one another.

Roger Caillois
French sociologist Roger Caillois, in his book Les jeux et les hommes (Games and Men),[6] defined a game as an activity that must have the following characteristics:
fun: the activity is chosen for its light-hearted character
separate: it is circumscribed in time and place
uncertain: the outcome of the activity is unforeseeable
non-productive: participation is not productive
governed by rules: the activity has rules that are different from everyday life
fictitious: it is accompanied by the awareness of a different reality

Chris Crawford
Computer game designer Chris Crawford attempted to define the term game[1] using a series of dichotomies:
Creative expression is art if made for its own beauty, and entertainment if made for money. (This is the least rigid of his definitions. Crawford acknowledges that he often chooses a creative path over conventional business wisdom, which is why he rarely produces sequels to his games.)
A piece of entertainment is a plaything if it is interactive. Movies and books are cited as examples of non-interactive entertainment.
If no goals are associated with a plaything, it is a toy. (Crawford notes that by his definition, (a) a toy can become a game element if the player makes up rules, and (b) The Sims and SimCity are toys, not games.) If it has goals, a plaything is a challenge.
If a challenge has no “active agent against whom you compete,” it is a puzzle; if there is one, it is a conflict. (Crawford admits that this is a subjective test. Video games with noticeably algorithmic artificial intelligence can be played as puzzles; these include the patterns used to evade ghosts in Pac-Man.)
Finally, if the player can only outperform the opponent, but not attack them to interfere with their performance, the conflict is a competition. (Competitions include racing and figure skating.) However, if attacks are allowed, then the conflict qualifies as a game.
Crawford's definition may thus be rendered as: an interactive, goal-oriented activity, active agents to play against, in which players (including active agents) can interfere with each other.

Other definitions
"A game is a system in which players engage in an artificial conflict, defined by rules, that results in a quantifiable outcome." (Katie Salen and Eric Zimmerman)
"A game is a form of art in which participants, termed players, make decisions in order to manage resources through game tokens in the pursuit of a goal." (Greg Costikyan)
"A game is an activity among two or more independent decision-makers seeking to achieve their objectives in some limiting context." (Clark C. Abt)
"At its most elementary level then we can define game as an exercise of voluntary control systems in which there is an opposition between forces, confined by a procedure and rules in order to produce a disequilibrial outcome." (Elliot Avedon and Brian Sutton-Smith)[10]
"A game is a form of play with goals and structure." (Kevin Maroney)[11]

Gameplay elements and classification
Games can be characterized by "what the player does."[1] This is often referred to as gameplay. Major key elements identified in this context are tools and rules which define the overall context of game and which in turn produce skill, strategy, and chance.[clarification needed]

Tools
Games are often classified by the components required to play them (e.g. miniatures, a ball, cards, a board and pieces, or a computer). In places where the use of leather is well established, the ball has been a popular game piece throughout recorded history, resulting in a worldwide popularity of ball games such as rugby, basketball, football, cricket, tennis, and volleyball. Other tools are more idiosyncratic to a certain region. Many countries in Europe, for instance, have unique standard decks of playing cards. Other games such as chess may be traced primarily through the development and evolution of its game pieces.
Many game tools are tokens, meant to represent other things. A token may be a pawn on a board, play money, or an intangible item such as a point scored.
Games such as hide-and-seek or tag do not utilise any obvious tool; rather, their interactivity is defined by the environment. Games with the same or similar rules may have different gameplay if the environment is altered. For example, hide-and-seek in a school building differs from the same game in a park; an auto race can be radically different depending on the track or street course, even with the same cars.

GAMES

2009-06-15T22:49:00.000-07:00

A game is a structured activity, usually undertaken for enjoyment and sometimes used as an educational tool. Games are distinct from work, which is usually carried out for remuneration, and from art, which is more concerned with the expression of ideas. However, the distinction is not clear-cut, and many games are also considered to be work (such as professional players of spectator sports/games) or art (such as jigsaw puzzles or games involving an artistic layout such as Mah-jongg solitaire).
Key components of games are goals, rules, challenge, and interaction. Games generally involve mental or physical stimulation, and often both. Many games help develop practical skills, serve as a form of exercise, or otherwise perform an educational, simulational or psychological role. According to Chris Crawford, the requirement for player interaction puts activities such as jigsaw puzzles and solitaire "games" into the category of puzzles rather than games.
Attested as early as 2600 BC, games are a universal part of human experience and present in all cultures. The Royal Game of Ur, Senet, and Mancala are some of the oldest known games

Music

2009-06-12T03:13:00.000-07:00

Music is composed and performed for many purposes, ranging from aesthetic pleasure, religious or ceremonial purposes, or as an entertainment product for the marketplace. Amateur musicians compose and perform music for their own pleasure, and they do not derive their income from music. Professional musicians are employed by a range of institutions and organisations, including armed forces, churches and synagogues, symphony orchestras, broadcasting or film production companies, and music schools. Professional musicians sometimes work as freelancers, seeking contracts and engagements in a variety of settings.
There are often many links between amateur and professional musicians. Beginning amateur musicians take lessons with professional musicians. In community settings, advanced amateur musicians perform with professional musicians in a variety of ensembles and orchestras. In some cases, amateur musicians attain a professional level of competence, and they are able to perform in professional performance settings. A distinction is often made between music performed for the benefit of a live audience and music that is performed for the purpose of being recorded and distributed through the music retail system or the broadcasting system. However, there are also many cases where a live performance in front of an audience is recorded and distributed (or broadcast).

Composition
Main article: Musical composition

An old songbook showing a composition
"Composition" is often classed as the creation and recording of music via a medium by which others can interpret it (i.e. paper or sound). Many cultures use at least part of the concept of preconceiving musical material, or composition, as held in western classical music. Even when music is notated precisely, there are still many decisions that a performer has to make. The process of a performer deciding how to perform music that has been previously composed and notated is termed interpretation. Different performers' interpretations of the same music can vary widely. Composers and song writers who present their own music are interpreting, just as much as those who perform the music of others or folk music. The standard body of choices and techniques present at a given time and a given place is referred to as performance practice, whereas interpretation is generally used to mean either individual choices of a performer, or an aspect of music which is not clear, and therefore has a "standard" interpretation.
In some musical genres, such as jazz and blues, even more freedom is given to the performer to engage in improvisation on a basic melodic, harmonic, or rhythmic framework. The greatest latitude is given to the performer in a style of performing called free improvisation, which is material that is spontaneously "thought of" (imagined) while being performed, not preconceived. Improvised music usually follows stylistic or genre conventions and even "fully composed" includes some freely chosen material. Composition does not always mean the use of notation, or the known sole authorship of one individual. Music can also be determined by describing a "process" which may create musical sounds; examples of this range from wind chimes, through computer programs which select sounds. Music which contains elements selected by chance is called Aleatoric music, and is associated with such composers as John Cage, Morton Feldman, and Witold Lutosławski.
Music can be composed for repeated performance or it can be improvised: composed on the spot. The music can be performed entirely from memory, from a written system of musical notation, or some combination of both. Study of composition has traditionally been dominated by examination of methods and practice of Western classical music, but the definition of composition is broad enough to include spontaneously improvised works like those of free jazz performers and African drummers such as the Ewe drummers.
What is important in understanding the composition of a piece is singling out its elements. An understanding of music's formal elements can be helpful in deciphering exactly how a piece is constructed. A universal element of music is how sounds occur in time, which is referred to as the rhythm of a piece of music. When a piece appears to have a changing time-feel, it is considered to be in rubato time, an Italian expression that indicates that the tempo of the piece changes to suit the expressive intent of the performer. Even random placement of random sounds, which occurs in musical montage, occurs within some kind of time, and thus employs time as a musical element.

Notation
Main article: Musical notation
Notation is the written expression of music notes and rhythms on paper using symbols. When music is written down, the pitches and rhythm of the music is notated, along with instructions on how to perform the music. The study of how to read notation involves music theory, harmony, the study of performance practice, and in some cases an understanding of historical performance methods. Written notation varies with style and period of music. In Western Art music, the most common types of written notation are scores, which include all the music parts of an ensemble piece, and parts, which are the music notation for the individual performers or singers. In popular music, jazz, and blues, the standard musical notation is the lead sheet, which notates the melody, chords, lyrics (if it is a vocal piece), and structure of the music. Scores and parts are also used in popular music and jazz, particularly in large ensembles such as jazz "big bands."
In popular music, guitarists and electric bass players often read music notated in tablature (often abbreviated as "tab"), which indicates the location of the notes to be played on the instrument using a diagram of the guitar or bass fingerboard. Tabulature was also used in the Baroque era to notate music for the lute, a stringed, fretted instrument. Notated music is produced as sheet music. To perform music from notation requires an understanding of both the rhythmic and pitch elements embodied in the symbols and the performance practice that is associated with a piece of music or a genre.

Improvisation
Musical improvisation is the creation of spontaneous music. Improvisation is often considered an act of instantaneous composition by performers, where compositional techniques are employed with or without preparation. Improvisation is a major part of some types of music, such as blues, jazz, and jazz fusion, in which instrumental performers improvise solos and melody lines. In the Western art music tradition, improvisation was an important skill during the Baroque era and during the Classical era; solo performers and singers would improvise virtuoso cadenzas during concerts. However, in the 20th and 21st century, improvisation played a smaller role in Western Art music.

Theory
Main article: Music theory
Music theory encompasses the nature and mechanics of music. It often involves identifying patterns that govern composers' techniques. In a more detailed sense, music theory (in the western system) also distills and analyzes the elements of music—rhythm, harmony (harmonic function), melody, structure, and texture. People who study these properties are known as music theorists.

Cognition
Further information: Hearing (sense) and Psychoacoustics

A chamber music group consisting of stringed instrument players, a flutist, and a harpsichordist perform in Salzburg
The field of music cognition involves the study of many aspects of music including how it is processed by listeners. Rather than accepting the standard practices of analyzing, composing, and performing music as a given, much research in music cognition seeks instead to uncover the mental processes that underlie these practices. Also, research in the field seeks to uncover commonalities between the musical traditions of disparate cultures and possible cognitive "constraints" that limit these musical systems. Questions regarding musical innateness, and emotional responses to music are also major areas of research in the field.
Deaf people can experience music by feeling the vibrations in their body, a process which can be enhanced if the individual holds a resonant, hollow object. A well-known deaf musician is the composer Ludwig van Beethoven, who composed many famous works even after he had completely lost his hearing. Recent examples of deaf musicians include Evelyn Glennie, a highly acclaimed percussionist who has been deaf since age twelve, and Chris Buck, a virtuoso violinist who has lost his hearing. This is relevant because it indicates that music is a deeper cognitive process than unexamined phrases such as, "pleasing to the ear" would suggest. Much research in music cognition seeks to uncover these complex mental processes involved in listening to music, which may seem intuitively simple, yet are vastly intricate and complex.

Sociology

This Song Dynasty (960–1279) painting, entitled the "Night Revels of Han Xizai", shows Chinese musicians entertaining guests at a party in a 10th century household.
Music is experienced by individuals in a range of social settings ranging from being alone to attending a large concert. Musical performances take different forms in different cultures and socioeconomic milieus. In Europe and North America, there is often a divide between what types of music are viewed as a "high culture" and "low culture." "High culture" types of music typically include Western art music such as Baroque, Classical, Romantic, and modern-era symphonies, concertos, and solo works, and are typically heard in formal concerts in concert halls and churches, with the audience sitting quietly in seats.
Other types of music—including, but not limited to, jazz, blues, soul, and country—are often performed in bars, nightclubs, and theatres, where the audience may be able to drink, dance, and express themselves by cheering. Until the later 20th century, the division between "high" and "low" musical forms was widely accepted as a valid distinction that separated out better quality, more advanced "art music" from the popular styles of music heard in bars and dance halls.
However, in the 1980s and 1990s, musicologists studying this perceived divide between "high" and "low" musical genres argued that this distinction is not based on the musical value or quality of the different types of music.[citation needed] Rather, they argued that this distinction was based largely on the socioeconomics standing or social class of the performers or audience of the different types of music.[citation needed] For example, whereas the audience for Classical symphony concerts typically have above-average incomes, the audience for a rap concert in an inner-city area may have below-average incomes. Even though the performers, audience, or venue where non-"art" music is performed may have a lower socioeconomic status, the music that is performed, such as blues, rap, punk, funk, or ska may be very complex and sophisticated.
When composers introduce styles of music which break with convention, there can be a strong resistance from academic music experts and popular culture. Late-period Beethoven string quartets, Stravinsky ballet scores, serialism, bebop-era jazz, hip hop, punk rock, and electronica have all been considered non-music by some critics when they were first introduced.[citation needed] Such themes are examined in the sociology of music. The sociological study of music, sometimes called sociomusicology, is often pursued in departments of sociology, media studies, or music, and is closely related to the field of ethnomusicology.

Acnos Energizer

MUSIC

2009-06-08T01:55:00.000-07:00

Performance is the physical expression of music. Often, a musical work is performed once its structure and instrumentation are satisfactory to its creators; however, as it gets performed, it can evolve and change. A performance can either be rehearsed or improvised. Improvisation is a musical idea created without premeditation, while rehearsal is vigorous repetition of an idea until it has achieved cohesion. Musicians will sometimes add improvisation to a well-rehearsed idea to create a unique performance.
Many cultures include strong traditions of solo and performance, such as in Indian classical music, and in the Western Art music tradition. Other cultures, such as in Bali, include strong traditions of group performance. All cultures include a mixture of both, and performance may range from improvised solo playing for one's enjoyment to highly planned and organised performance rituals such as the modern classical concert, religious processions, music festivals or music competitions. Chamber music, which is music for a small ensemble with only a few of each type of instrument, is often seen as more intimate than symphonic works.

Aural tradition
Many types of music, such as traditional blues and folk music were originally preserved in the memory of performers, and the songs were handed down orally, or aurally (by ear). When the composer of music is no longer known, this music is often classified as "traditional". Different musical traditions have different attitudes towards how and where to make changes to the original source material, from quite strict, to those which demand improvisation or modification to the music. A culture's history may also be passed by ear through song.

Ornamentation
Main article: Ornament (music)
The detail included explicitly in the music notation varies between genres and historical periods. In general, art music notation from the 17th through the 19th century required performers to have a great deal of contextual knowledge about performing styles. For example, in the 17th and 18th century, music notated for solo performers typically indicated a simple, unornamented melody. However, it was expected that performers would know how to add stylistically-appropriate ornaments such as trills and turns. In the 19th century, art music for solo performers may give a general instruction such as to perform the music expressively, without describing in detail how the performer should do this. It was expected that the performer would know how to use tempo changes, accentuation, and pauses (among other devices) to obtain this "expressive" performance style. In the 20th century, art music notation often became more explicit and used a range of markings and annotations to indicate to performers how they should play or sing the piece.
In popular music and jazz, music notation almost always indicates only the basic framework of the melody, harmony, or performance approach; musicians and singers are expected to know the performance conventions and styles associated with specific genres and pieces. For example, the "lead sheet" for a jazz tune may only indicate the melody and the chord changes. The performers in the jazz ensemble are expected to know how to "flesh out" this basic structure by adding ornaments, improvised music, and chordal accompaniment.

MUSIC

2009-06-05T02:07:00.000-07:00

The field of music history, sometimes called historical musicology, is the highly diverse subfield of the broader discipline of musicology that studies the composition, performance, reception, and criticism of music over time. Historical studies of music are for example concerned with a composer's life and works, the developments of styles and genres (such as baroque concertos), the social function of music for a particular group of people (such as music at the court), or the modes of performance at a particular place and time (such as the performance forces of Johann Sebastian Bach's choir in Leipzig).
In theory, "music history" could refer to the study of the history of any type or genre of music (e.g., the history of Indian music or the history of rock). In practice, these research topics are nearly always categorized as part of ethnomusicology or cultural studies, whether or not they are ethnographically based.
The methods of music history include source studies (esp. manuscript studies), paleography, philology (especially textual criticism), style criticism, historiography (the choice of historical method), musical analysis, and iconography. The application of musical analysis to further these goals is often a part of music history, though pure analysis or the development of new tools of music analysis is more likely to be seen in the field of music theory. (For a more detailed discussion of the methods see the section on "Research in Music History" below) Some of the intellectual products of music historians include editions of musical works, biography of composers and other musicians, studies of the relationship between words and music, and the reflections upon the place of music in society.

Here you all can find latest movies song's lyrics:

MUSIC

2009-06-02T23:07:00.000-07:00

Non-Western Classical traditions
Indian classical music is one of the oldest musical traditions in the world. The Indus Valley civilization has sculptures which show dance and old musical instruments, like the seven holed flute. Various types of stringed instruments and drums have been recovered from Harrappa and Mohenjo Daro by excavations carried out by Sir Mortimer Wheeler.The Rigveda has elements of present Indian music, with a musical notation to denote the metre and the mode of chanting.Indian classical music (marga) is monophonic, and based around a single melody line or raga rhythmically organized through talas. Carnatic music is largely devotional; the majority of the songs are addressed to the Hindu deities. There are a lot of songs emphasising love and other social issues. Hindustani music was also influenced by the Persian performance practices of the Afghan Mughals.
Asian music covers the music cultures of Arabia, Central Asia, East Asia, South Asia, and Southeast Asia. Chinese classical music, the traditional art or court music of China, has a history stretching over around three thousand years. It has its own unique systems of musical notation, as well as musical tuning and pitch, musical instruments and styles or musical genres. Chinese music is pentatonic-diatonic, having a scale of twelve notes to an octave (5+7 = 12) as does European-influenced music. Persian music is the music of Persia and Persian language countries: musiqi, the science and art of music, and muzik, the sound and performance of music (Sakata 1983). See also: Music of Iran, Music of Afghanistan, Music of Tajikistan, Music of Uzbekistan).
The music of Greece was a major part of ancient Greek theater. In Ancient Greece, mixed-gender choruses performed for entertainment, celebration and spiritual reasons. Instruments included the double-reed aulos and the plucked string instrument, the lyre, especially the special kind called a kithara. Music was an important part of education in ancient Greece, and boys were taught music starting at age six. Greek musical literacy created a flowering of development; Greek music theory included the Greek musical modes, eventually became the basis for Western religious music and classical music. Later, influences from the Roman Empire, Eastern Europe and the Byzantine Empire changed Greek music

lyrics of songs:
DOSTANA Movie Songs LyricsMy Desi Girl Lyrics Hindi Song Title: My Desi Girl : DOSTANA Singer(s): SHANKAR MAHADEVAN, SUNIDHI CHAUHAN Cast(s): ABHISHEK BACHCHAN , JOHN ABRAHAM , PRIYANKA CHOPRA

My Desi Girl, My Desi Girl, Girl Girl Girl Girl…… ) - 2
Jhoomka Girade, Jo Mila Le Agar Woh Nazar Se Nazar Mitade
Nachke Dikhade, Sabki Dhadhkan Bhi Kadam Se Kadam Milade
Lehron Se Chal Ke Jaal Bicha Ke,Dil Ko Ye Behaal BanadeSaare Deewane Maane, (Na Dekhi Koi Aisi Girl ) - 2
Dekhi Lakh Lakh Pardesi Girl, Ain’t Nobody Like My Desi GirlDekhi Lakh Lakh Pardesi Girl, Sab Toh Soni N Saadi Desi GirlWho’s The Hottest Girl In The World, My Desi Girl, My Desi Girl
Thumka Lagaike She’ll Rock Your World, My Desi Girl, My Desi Girl

My Desi Girl, My Desi Girl, Girl Girl Girl Girl…… Pade Kamar Pe Jo Nazar, Saare Saapnon Mein Rang Bhar Jaaye Jo Tham Le Woh Haath Toh, Haske Hi Aashiq Mar Jaayein
Dhoondon Jahan Mein Chahe Kahin, Na Tumko Milegi Koi Aisi GirlDekhi Lakh Lakh Pardesi Girl, Ain’t Nobody Like My Desi Girl
Dekhi Lakh Lakh Pardesi Girl, Sab Toh Soni N Saadi Desi GirlWho’s The Hottest Girl In The World, My Desi Girl, My Desi GirlThumka Lagaike She’ll Rock Your World, My Desi Girl, My Desi Girl
My Desi Girl, My Desi Girl, Girl Girl Girl Girl……Jahan Jahan Bhi Jau Main, Saari Nazrein Toh Peche Peche AiyeRuku Zara Mein Jo Yahan, Thandi Thandi Saari Saase Tham JayeSabki Nigahon Ne Hai Kaha, Ke Khwaabon Mein Hai Dekhi (Meri Jaisi Girl ) - 2

Dekhi Lakh Lakh Pardesi Girl, Ain’t Nobody Like My Desi GirlDekhi Lakh Lakh Pardesi Girl, Sab Toh Soni N Saadi Desi GirlWho’s The Hottest Girl In The World, My Desi Girl,My Desi GirlThumka Lagaike She’ll Rock Your World, My Desi Girl,My Desi Girl

DOSTANA Movie Songs LyricsJaane Kyun Lyrics Hindi Song Title: Jaane Kyun : DOSTANA Singer(s): VISHAL Cast(s): ABHISHEK BACHCHAN , JOHN ABRAHAM , PRIYANKA CHOPRA

(I' ll Be All Right) - 2
I' ll Be All RightTu Hai To Tedhi Medhi RaheinUlti Pulti Baatein, Seedhi Lagti Hai Tu Hai To Jhoothe Muthe VaadeinDushman Ke Iraade, Sacche Lagtein Hain..Jo Dil Mein Taare Vaare De Jaga, Woh Tu Hi Hai, Tu Hi Hai Jo Roote Roote De Hasa, Tu Hi Hai Wohi..(Jaane Kyun Jaane Kyun Dil Jaanta Hai.., Tu Hai To, I' ll Be All RightI' ll Be All Right, I' ll Be All Right) - 2
Saari Duniya Ek Taraf Hai, Ek Taraf Hai HumHar Khushi To Door Bhage, Mil Rahein Hai GumBut When U Smile For Me, World Seems All RightYeh Meri Zindagi, Pal Mein Khil Jaaye, Jaane Kyun..(Jaane Kyun.., Jaane Kyun Dil Jaanta Hai.., Tu Hai To, I' ll Be All RightI' ll Be All Right, I' ll Be All Right) - 2(Yeah Yeah Yeah, I' ll Be All Right, I' ll Be All Right, I' ll Be All RightYeah Yeah Yeah, I' ll Be All Right, I' ll Be.. All.. Right..) - 2Oh Oo.., Chote Chote Kuch Palon Ka, Dostana YeahJaane Kyun Abb Lag Raha Hai, Jaana Maana YeahCos When Smile For Me, World Seems All Right Yeah Saare Pal Yehi, Yuhi Tham Se Jaaye, Jaane Kyun, Jaane Kyun(Jaane Kyun.., Jaane Kyun Dil Jaanta Hai.., Tu Hai To, I' ll Be All RightI' ll Be All Right, I' ll Be All Right) - 2

Tu Hai To Tedhi Medhi RaheinUlti Pulti Baatein, Seedhi Lagti Hai Tu Hai To Jhoothe Muthe VaadeinDushman Ke Iraade, Sacche Lagtein HainJo Dil Mein Taare Vaare De Jaga, Woh Tu Hi Hai,Tu Hi Hai Jo Roote Roote De Hasa, Tu Hi Hai Wohi..(Jaane Kyun.., Jaane Kyun Dil Jaanta Hai.., Tu Hai To, I' ll Be All RightI' ll Be All Right, I' ll Be All Right) - 3

2009-05-30T22:08:00.000-07:00

Ancient music can only be imagined by scholars, based on findings from a range of paleolithic sites, such as bones in which lateral holes have been pierced: these are usually identified as flutes,blown at one end like the Japanese shakuhachi. Instruments, such as the seven-holed flute and various types of stringed instruments have been recovered from the Indus Valley Civilization archaeological sites.
India has one of the oldest musical traditions in the world—references to Indian classical music (marga) can be found in the ancient scriptures of the Hindu tradition, the Vedas. The traditional music of China has a history stretching for around three thousand years. Music was an important part of cultural and social life in Ancient Greece: mixed-gender choruses performed for entertainment, celebration and spiritual ceremonies; musicians and singers had a prominent role in ancient Greek theater. In the 9th century, the Arab scholar al-Farabi wrote a book on music titled Kitab al-Musiqi al-Kabir ("Great Book of Music"). He played and invented a variety of musical instruments and devised the Arab tone system of pitch organisation, which is still used in Arabic music.

Western cultures
During the Medieval music era (500-1400), the only European repertory which has survived from before about 800 is the monophonic liturgical plainsong of the Roman Catholic Church, the central tradition of which was called Gregorian chant. Alongside these traditions of sacred and church music there existed a vibrant tradition of secular song. From the Renaissance music era (1400-1600), much of the surviving music of 14th century Europe is secular. By the middle of the 15th century, composers and singers used a smooth polyphony for sacred musical compositions. The introduction of commercial printing helped to disseminate musical styles more quickly and across a larger area.

Allegory of Music, by Filippino Lippi
The era of Baroque music (1600-1750) began when the first operas were written and when contrapuntal music became prevalent. German Baroque composers wrote for small ensembles including strings, brass, and woodwinds, as well as choirs, pipe organ, harpsichord, and clavichord. During the Baroque period, several major music forms were defined that lasted into later periods when they were expanded and evolved further, including the fugue, the invention, the sonata, and the concerto. The music of the Classical period (1750-1800) is characterized by homophonic texture, often featuring a prominent melody with accompaniment. These new melodies tended to be almost voice-like and singable. The now popular instrumental music was dominated by further evolution of musical forms initially defined in the Baroque period: the sonata, and the concerto, with the addition of the new form, the symphony. Joseph Haydn and Wolfgang Amadeus Mozart are among the central figures of the Classical period.
In 1800, the Romantic era (1800-1890s) in music developed, with Ludwig van Beethoven and Franz Schubert as transitional composers who introduced a more dramatic, expressive style. During this era, existing genres, forms, and functions of music were developed, and the emotional and expressive qualities of music came to take precedence over technique and tradition. In Beethoven's case, motifs (developed organically) came to replace melody as the most significant compositional unit. The late 19th century saw a dramatic expansion in the size of the orchestra, and in the role of concerts as part of urban society. Later Romantic composers created complex and often much longer musical works. They used more complex chords and used more dissonance to create dramatic tension. With 20th century music, there was a vast increase in music listening as the radio gained popularity and phonographs were used to replay and distribute music. The focus of art music was characterized by exploration of new rhythms, styles, and sounds. Igor Stravinsky, Arnold Schoenberg, and John Cage were all influential composers in 20th century art music.
Jazz evolved and became a significant genre of music over the course of the 20th century, and during the second half of that century, rock music did the same. Jazz is an American musical art form which originated in the beginning of the 20th century in African American communities in the Southern United States from a confluence of African and European music traditions. The style's West African pedigree is evident in its use of blue notes, improvisation, polyrhythms, syncopation, and the swung note.From its early development until the present, jazz has also incorporated music from 19th and 20th century American popular music.Jazz has, from its early 20th century inception, spawned a variety of subgenres, ranging from New Orleans Dixieland (1910s) to 1970s and 1980s-era jazz-rock fusion.
Rock music is a genre of popular music that developed in the 1960s from 1950s rock and roll, rockabilly, blues, and country music. The sound of rock often revolves around the electric guitar or acoustic guitar, and it uses a strong back beat laid down by a rhythm section of electric bass guitar, drums, and keyboard instruments such as organ, piano, or, since the 1970s, digital synthesizers. Along with the guitar or keyboards, saxophone and blues-style harmonica are used as soloing instruments. In its "purest form", it "has three chords, a strong, insistent back beat, and a catchy melody."In the late 1960s and early 1970s, rock music branched out into different subgenres, ranging from blues rock and jazz-rock fusion to heavy metal and punk rock, as well as the more classical influenced genre of progressive rock.

Some popular songs Lyrics:
Guzarish (Tu Meri Adhuri Pyas Pyas) Lyrics Hindi Song Title: Guzarish (Tu Meri Adhuri Pyas Pyas) : GHAJINI Singer(s): JAVED ALI Cast(s): AAMIR KHAN , ASIN THOTTUMKAL , JIAH KHAN

Hmmmmm Mm…
Tu Meri Adhuri Pyas Pyas, Tu Agayi Mann Ko Ras Ras, Aab Tho...
Tu Meri Adhuri Pyas Pyas, Tu Agayi Mann Ko Ras Ras
Aab Tho Thu Aaja Pass Paaaas, Hain Guzaaarish
Hain Haal To Dil Ka Tang Tang, Thu Rang Ja Mere Rang Rang
Bas Chalna Mere Sang Sang, Hain Guzaaarish
Kehde Thu Han Tho Zindagi, Chainon Se Chhutke Hasegi
Moti Hunge Moti Rahon Meinnn, Yeh Yeh Yeh
Tu Meri Adhuri Pyas Pyas, Tu Agayi Mann Ko Ras Ras
Aab Tho Thu Aaja Pass Pas..., Hain Guzaaarish
Khwaab Lekke, Raaton Mein Chal Raha Hon
Takrana Jao Kahin...
Aasha Ki Lon Hain Roshan, Phir Bhi Toffan Ka Dhar Hain
Lon Bhuj Na Jaye Kahin...
Bas Eak Haan Ki Guzaarish, Phir Hogi Khusiyon Ki Baarish
Tu Meri Adhuri Pyas Pyas, Tu Agayi Mann Ko Ras Ras
Aab Tho Thu Aaja Pass Paaaas, Hain Guzaaarish
Hmmm Mmm Mm Mmm Mmm Mm Mmm Hmmmmm Mm…
Oho Ohhhhhhhhhh Oho Ohhhhhhhhh..
Chanda Hain Aasman Hain, Aur Badal Bhee Gane Hain
Yeh Chandaaa Chup Jaye Na...
Tanhayi Das Rahin Hain, Aur Dhadkan Bad Rahi Hain
Eak Pal Bhi Chain Aaye Na...
Kaisi Aajab Dastaan Hain, Bheechainiyan Baas Yahan Hain Oh
Tu Meri Adhuri Pyas Pyas, Tu Agayi Mann Ko Ras Ras
Aab Tho Thu Aaja Pass Paaaas, Hain Guzaaarish
Hain Haal Tho Dil Ka Thang Thang, Thu Rang Ja Mere Rang Rang
Bas Chalna Mere Sang Sang, Hain Guzaaarish
Kehde Thu Han Tho Zindagi, Chainon Se Chhutke Hasegi
Moti Hunge Moti Rahon Meinnn, Yeh Yeh Yeh
Tu Meri Adhuri Pyas Pyas..
Hmmm Mmm Mm Mmm Mmm Mm Mmm Hmmmmm Mm…
Oho Ohhhhhhhhhh Oho Ohhhhhhhhh..

Kaise Mujhe Tum Mil Gayi Lyrics Hindi Song Title: Kaise Mujhe Tum Mil Gayi : GHAJINI Singer(s): SHREYA GHOSAL, BENNY DAYAL Cast(s): AAMIR KHAN , ASIN THOTTUMKAL , JIAH KHAN

Ho..Oo.., Ho Oo.., Hooo.., Ho.. Ho..Kaise Mujhe Tum Mil Gayi, Kismat Pe Aaye Naa Yakeen Utar Aayi Jeet Mein, Jaise Chaand Utar Ta HaiKabhi Haule Haule Dheere SeGun Guni Dhoop Ki Tarah Se Tarango Mein TumChhoo Ke Mujhe Guzari Ho YuhDekhu Tumhe Ya Main Sunoo, Tum Ho Sukoon Tum Ho Junoon..., Kyun Pehre Raat Aayi TumKaise Mujhe Tum Mil Gayi, Kismat Pe Aaye Naa Yakeen
Main To Yeh Sochta Tha, Ke Aaj Kal Kuch Bataane KoFursat Nahi Phir Bhi Tumhe Banaake WohMeri Nazar Main Chadh Gaya, Ruit Pe Duaa..Aur Ban GayaBadle Raaste Jharne Aur Nadi, Badli Deep Ki Tin TinChhede Zindagi Dhun Koi Nahi, Badli Barkhaa Ki RimjhimBadlengi Rituein Ada.., Par Main Rahoongi Sada..Usi Tarah Teri Baahon Mein Baahein Daal Ke Har Lamha Har PalZindagi Sitaar Hogayi, Rimjhim Malhaa HogayiMujhe Aata Nahi Kismat Pe Apni Yakeen Kaise Mujhko Mili Tu

YUVVRAAJ Movie Songs LyricsTu Meri Dost Hain Lyrics Hindi Song Title: Tu Meri Dost Hain : YUVVRAAJ Singer(s): BENNY DAYAL, SHREYA GHOSAL, A R RAHMAN Cast(s): SALMAN KHAN , ANIL KAPOOR , KATRINA KAIF , ZAYED KHAN , MITHUN CHAKRABORTY

Aaja Main Hawaon Pe Bithake Le ChalunTu Hi Toh, Tu Hi Toh Meri Doost HainAaja Main Khalaon Mein Uthake Le ChalunTu Hi Toh Meri Doost HainAwaaz Ka Dariya Hoon, Behta Hoon Main Nili Raaton MeinMain Jaagta Rehta Hoon, Neend Bhari Jheel Si Aankhon MeinAwaaz Hoon Main…Aaja Main Hawaon Pe Bithake Le ChaloonTu Hi Toh, Tu Hi Toh Meri Doost HainAaja Main Khalaon Mein Uthake Le ChaloonTu Hi Toh Meri Doost Hain
Raat Mein Chandni Kabhi, Aisi Gungunati HainSunn Zara Lagta Hain Tumse, Awaaz Milati HainMain Khayalon Ki Mehek Hoon, Gungunate Hain Saaz ParHo Sake Toh Milale, Awaaz Ku Le Saaz Par..Aaja Main Hawaon Pe Bithake Le ChalunTu Hi Toh Meri Doost HainAaja Main Khalaon Mein Uthake Le ChaloonTu Hi Toh Meri Doost HainAwaaz Ka Dariya Hoon, Behta Hoon Main Nili Raaton MeinMain Jaagta Rehta Hoon, Neend Bhari Jheel Si Aankhon MeinAwaaz Hoon Main…O Kabhi Kehta Hai Saahil, Jahan Shaam Utarti HainKehte Hain Samunder Se, Ek Pari Gujarti HainWoh Raat Ki Rani Hain, Sargam Par Chalti HainRe Sa Re Sa Re Sa, Sa Re Sa Re Sa ReAaja Main Hawaon Pe Bithake Le ChaloonTu Hi Toh, Tu Hi Toh Mera Doost HainAaja Main Khalaon Mein Uthake Le ChaloonTu Hi Toh Mera Doost HainAwaaz Ka Dariya Hoon, Behti Hoon Mein Nilli Raaton MeinMain Jagti Rehti Hoon, Neend Bhari Jheel Si Aankhon MeinAwaaz Hoon Main…...Awaaz Hoon Main…...

MUSIC

2009-05-28T22:46:00.000-07:00

History of music

Music is found in every known culture, past and present, varying wildly between times and places. Scientists now believe that modern humans emerged from Africa 160,000 years ago. Around 50,000 years ago these humans began to disperse from Africa reaching all the habitable continents. Since all people of the world, including the most isolated tribal groups, have a form of music, scientists conclude that music must have been present in the ancestral population prior to the dispersal of humans around the world. Consequently music must have been in existence for at least 50,000 years and the first music must have been invented in Africa and then evolved to become a fundamental constituent of human life.
A culture's music is influenced by all other aspects of that culture, including social and economic organization and experience, climate, and access to technology. The emotions and ideas that music expresses, the situations in which music is played and listened to, and the attitudes toward music players and composers all vary between regions and periods. "Music history" is the distinct subfield of musicology and history which studies music (particularly western art music) from a chronological perspective.

Medieval music

While musical life was undoubtedly rich in the early Medieval era, as attested by artistic depictions of instruments, writings about music, and other records, the only repertory of music which has survived from before 800 to the present day is the plainsong liturgical music of the Roman Catholic Church, the largest part of which is called Gregorian chant. Pope Gregory I, who gave his name to the musical repertory and may himself have been a composer, is usually claimed to be the originator of the musical portion of the liturgy in its present form, though the sources giving details on his contribution date from more than a hundred years after his death. Many scholars believe that his reputation has been exaggerated by legend. Most of the chant repertory was composed anonymously in the centuries between the time of Gregory and Charlemagne.
During the 9th century several important developments took place. First, there was a major effort by the Church to unify the many chant traditions, and suppress many of them in favor of the Gregorian liturgy. Second, the earliest polyphonic music was sung, a form of parallel singing known as organum. Third, and of greatest significance for music history, notation was reinvented after a lapse of about five hundred years, though it would be several more centuries before a system of pitch and rhythm notation evolved having the precision and flexibility that modern musicians take for granted.
Several schools of polyphony flourished in the period after 1100: the St. Martial school of organum, the music of which was often characterized by a swiftly moving part over a single sustained line; the Notre Dame school of polyphony, which included the composers Léonin and Pérotin, and which produced the first music for more than two parts around 1200; the musical melting-pot of Santiago de Compostela in Galicia, a pilgrimage destination and site where musicians from many traditions came together in the late Middle Ages, the music of whom survives in the Codex Calixtinus; and the English school, the music of which survives in the Worchester Fragments and the Old Hall Manuscript. Alongside these schools of sacred music a vibrant tradition of secular song developed, as exemplified in the music of the troubadours, trouvères and Minnesänger. Much of the later secular music of the early Renaissance evolved from the forms, ideas, and the musical aesthetic of the troubadours, courtly poets and itinerant musicians, whose culture was largely exterminated during the Albigensian Crusade in the early 13th century.
Forms of sacred music which developed during the late 13th century included the motet, conductus, discant, and clausulae. One unusual development was the Geisslerlieder, the music of wandering bands of flagellants during two periods: the middle of the 13th century (until they were suppressed by the Church); and the period during and immediately following the Black Death, around 1350, when their activities were vividly recorded and well-documented with notated music. Their music mixed folk song styles with penitential or apocalyptic texts. The 14th century in European music history is dominated by the style of the ars nova, which by convention is grouped with the medieval era in music, even though it had much in common with early Renaissance ideals and aesthetics. Much of the surviving music of the time is secular, and tends to use the formes fixes: the ballade, the virelai, the lai, the rondeau, which correspond to poetic forms of the same names. Most pieces in these forms are for one to three voices, likely with instrumental accompaniment: famous composers include Guillaume de Machaut and Francesco Landini.

Renaissance music

The beginning of the Renaissance in music is not as clearly marked as the beginning of the Renaissance in the other arts, and unlike the Renaissance in the other arts, it did not begin in Italy, but in northern Europe, specifically in the area currently comprising central and northern France, the Netherlands, and Belgium. The style of the Burgundian composers, as the first generation of the Franco-Flemish school is known, was at first a reaction against the excessive complexity and mannered style of the late 14th century ars subtilior, and contained clear, singable melody and balanced polyphony in all voices. The most famous composers of the Burgundian school in the mid-15th century are Guillaume Dufay, Gilles Binchois, and Antoine Busnois.
By the middle of the 15th century, composers and singers from the Low Countries and adjacent areas began to overspread Europe, moving especially into Italy where they were employed by the papal chapel and the aristocratic patrons of the arts, such as the Medici, the Este family in Ferrara, and the Sforza family in Milan. They carried their style with them: smooth polyphony which could be adapted for sacred or secular use as appropriate. Principal forms of sacred musical composition at the time were the mass, the motet, and the laude; secular forms included the chanson, the frottola, and later the madrigal.
The invention of printing had an immense influence on the dissemination of musical styles, and along with the movement of the Franco-Flemish musicians throughout Europe, contributed to the establishment of the first truly international style in European music since the unification of Gregorian chant under Charlemagne seven hundred years before. Composers of the middle generation of the Franco-Flemish school included Johannes Ockeghem, who wrote music in a contrapuntally complex style, with varied texture and an elaborate use of canonical devices; Jacob Obrecht, one of the most famous composers of masses in the last decades of the 15th century; and Josquin Desprez, probably the most famous composer in Europe before Palestrina, and who during the 16th century was renowned as one of the greatest artists in any form.
Music in the generation after Josquin explored increasing complexity of counterpoint; possibly the most extreme expression of this tendency is in the music of Nicolas Gombert, whose contrapuntal complexities influenced early instrumental music, such as the canzona and the ricercar, ultimately culminating in Baroque fugal forms.

Portrait of Renaissance composer Claudio Monteverdi in Venice, 1640, by Domenico Fetti.
By the middle of the 16th century, the international style began to break down, and several highly diverse stylistic trends became evident: a trend towards simplicity in sacred music, as directed by the Counter-Reformation Council of Trent, and as exemplified in the austere perfection of the music of Giovanni Pierluigi da Palestrina; a trend towards complexity and chromaticism in the madrigal, which reached its extreme expression in the avant-garde style of the Ferrara School of Luzzaschi, and the late century madrigalist Carlo Gesualdo; and the grandiose, sonorous music of the Venetian school, which took advantage of the architecture of the Basilica San Marco di Venezia to create a music of antiphonal contrasts. The music of the Venetian school can be seen on the cusp of the Renaissance and the Baroque eras, and included the development of orchestration, ornamented instrumental parts, and continuo bass parts, all of which occurred within a span of several decades around 1600. Famous composers in Venice included the Gabrielis, Andrea and Giovanni, as well as Claudio Monteverdi, one of the most significant innovators at the end of the era.
Most parts of Europe had active, and well-differentiated, musical traditions by late in the century. In England, composers such as Thomas Tallis and William Byrd wrote sacred music in a style similar to that written on the continent, while an active group of home-grown madrigalists adapted the Italian form for English tastes: famous composers included Thomas Morley, John Wilbye and Thomas Weelkes. Spain developed instrumental and vocal styles of its own, with Tomás Luis de Victoria writing refined music similar to that of Palestrina, and numerous other composers writing for a new instrument called the guitar. Germany cultivated polyphonic forms built on the Protestant chorales, which replaced the Roman Catholic Gregorian Chant as a basis for sacred music, and imported wholesale the style of the Venetian school (the appearance of which defined the start of the Baroque era there). In addition, German composers wrote enormous amounts of organ music, establishing the basis for the later spectacular flowering of the Baroque organ style which culminated in the work of J.S. Bach. France developed a unique style of musical diction known as musique mesurée, used in secular chansons, with composers such as Guillaume Costeley and Claude Le Jeune prominent in the movement.
One of the most revolutionary movements in the era took place in Florence in the 1570s and 1580s, with the work of the Florentine Camerata, who ironically had a reactionary intent: dissatisfied with what they saw as contemporary musical depravities, their goal was to restore the music of the ancient Greeks. Chief among them were Vincenzo Galilei, the father of the astronomer, and Giulio Caccini. The fruits of their labors was a declamatory melodic singing style known as monody, and a corresponding dramatic form consisting of staged, acted monody: a form known today as opera. The first operas, written around 1600, also define the end of the Renaissance and the beginning of the Baroque eras.
Music prior to 1600 was modal rather than tonal. Several theoretical developments late in the 16th century, such as the writings on scales on modes by Gioseffo Zarlino and Franchinus Gaffurius, led directly to the development of common practice tonality. The major and minor scales began to predominate over the old church modes, a feature which was at first most obvious at cadential points in compositions, but gradually became pervasive. Music after 1600, beginning with the tonal music of the Baroque era, is often referred to as belonging to the common practice period.

MUSIC

2009-05-23T19:55:00.000-07:00

Music is an art form whose medium is sound organized in time. Common elements of music are pitch (which governs melody and harmony), rhythm (and its associated concepts tempo, meter, and articulation), dynamics, and the sonic qualities of timbre and texture. The word derives from Greek μουσική (mousike), "(art) of the Muses".
The creation, performance, significance, and even the definition of music vary according to culture and social context. Music ranges from strictly organized compositions (and their recreation in performance), through improvisational music to aleatoric forms. Music can be divided into genres and subgenres, although the dividing lines and relationships between music genres are often subtle, sometimes open to individual interpretation, and occasionally controversial. Within "the arts", music may be classified as a performing art, a fine art, and auditory art.
To people in many cultures, music is inextricably intertwined into their way of life. Greek philosophers and ancient Indians defined music as tones ordered horizontally as melodies and vertically as harmonies. Common sayings such as "the harmony of the spheres" and "it is music to my ears" point to the notion that music is often ordered and pleasant to listen to. However, 20th-century composer John Cage thought that any sound can be music, saying, for example, "There is no noise, only sound." According to musicologist Jean-Jacques Nattiez, "the border between music and noise is always culturally defined—which implies that, even within a single society, this border does not always pass through the same place; in short, there is rarely a consensus.... By all accounts there is no single and intercultural universal concept defining what music might be, except that it is 'sound through time'

Prehistoric eras and antiquity
Ancient music can only be imagined by scholars, based on findings from a range of paleolithic sites, such as bones in which lateral holes have been pierced: these are usually identified as flutes,[4] blown at one end like the Japanese shakuhachi. Instruments, such as the seven-holed flute and various types of stringed instruments have been recovered from the Indus Valley Civilization archaeological sites.
India has one of the oldest musical traditions in the world—references to Indian classical music (marga) can be found in the ancient scriptures of the Hindu tradition, the Vedas. The traditional music of China has a history stretching for around three thousand years. Music was an important part of cultural and social life in Ancient Greece: mixed-gender choruses performed for entertainment, celebration and spiritual ceremonies; musicians and singers had a prominent role in ancient Greek theater. In the 9th century, the Arab scholar al-Farabi wrote a book on music titled Kitab al-Musiqi al-Kabir ("Great Book of Music"). He played and invented a variety of musical instruments and devised the Arab tone system of pitch organisation, which is still used in Arabic music.