Personal computer

Personal computer

Overview
A personal computer is any general-purpose computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user
End-user
Economics and commerce define an end user as the person who uses a product. The end user or consumer may differ from the person who purchases the product...

 with no intervening computer operator. In contrast, the batch processing or time-sharing models allowed large expensive mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

 systems to be used by many people, usually at the same time. Large data processing systems require a full-time staff to operate efficiently.

Software applications for personal computers include, but are not limited to, word processing
Word processing
Word processing is the creation of documents using a word processor. It can also refer to advanced shorthand techniques, sometimes used in specialized contexts with a specially modified typewriter.-External links:...

, spreadsheets, databases, Web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

s and e-mail
E-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...

 clients, digital media
Digital media
Digital media is a form of electronic media where data is stored in digital form. It can refer to the technical aspect of storage and transmission Digital media is a form of electronic media where data is stored in digital (as opposed to analog) form. It can refer to the technical aspect of...

 playback, games
Personal computer game
A PC game, also known as a computer game, is a video game played on a personal computer, rather than on a video game console or arcade machine...

, and myriad personal productivity and special-purpose software applications.
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Unanswered Questions
Encyclopedia
A personal computer is any general-purpose computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user
End-user
Economics and commerce define an end user as the person who uses a product. The end user or consumer may differ from the person who purchases the product...

 with no intervening computer operator. In contrast, the batch processing or time-sharing models allowed large expensive mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

 systems to be used by many people, usually at the same time. Large data processing systems require a full-time staff to operate efficiently.

Software applications for personal computers include, but are not limited to, word processing
Word processing
Word processing is the creation of documents using a word processor. It can also refer to advanced shorthand techniques, sometimes used in specialized contexts with a specially modified typewriter.-External links:...

, spreadsheets, databases, Web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

s and e-mail
E-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...

 clients, digital media
Digital media
Digital media is a form of electronic media where data is stored in digital form. It can refer to the technical aspect of storage and transmission Digital media is a form of electronic media where data is stored in digital (as opposed to analog) form. It can refer to the technical aspect of...

 playback, games
Personal computer game
A PC game, also known as a computer game, is a video game played on a personal computer, rather than on a video game console or arcade machine...

, and myriad personal productivity and special-purpose software applications. Modern personal computers often have connections to the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

, allowing access to the World Wide Web
World Wide Web
The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...

 and a wide range of other resources. Personal computers may be connected to a local area network
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...

 (LAN), either by a cable or a wireless connection. A personal computer may be a desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

 or a laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

, tablet
Tablet computer
A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...

, or a handheld PC
Handheld PC
A Handheld PC, or H/PC for short, is a term for a computer built around a form factor which is smaller than any standard laptop computer. It is sometimes referred to as a Palmtop. The first handheld device compatible with desktop IBM personal computers of the time was the Atari Portfolio of 1989...

.

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 software
Commercial software
Commercial software, or less commonly, payware, is computer software that is produced for sale or that serves commercial purposes.Commercial software is most often proprietary software, but free software packages may also be commercial software....

 and free software
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

, which is provided in ready-to-run or ready-to-compile
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...

 form. Since the early 1990s, Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

 software and Intel hardware have dominated much of the personal computer market, first with MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...

 and then with the Wintel
Wintel
Wintel is a portmanteau of Windows and Intel, referring to personal computers using Intel x86 compatible processors running Microsoft Windows...

 platform. Alternatives to Microsoft's Windows operating systems include Apple's Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 and the open-source Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 OSes. AMD is the major alternative to Intel's central processing units. Applications and games for PCs are typically developed and distributed independently from the hardware or OS manufacturers, whereas software for many mobile phones and other portable systems is approved and distributed through a centralized online store.

In July and August 2011, marketing businesses and journalists began to talk about the 'Post-PC Era', in which the desktop form factor was being replaced with more portable computing such as netbooks
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

, Tablet PCs
Tablet computer
A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...

, and smartphones.

History


In what was later to be called The Mother of All Demos
The Mother of All Demos
The Mother of All Demos is a name given to Douglas Engelbart's December 9, 1968, demonstration of experimental computer technologies that are now commonplace...

, SRI
SRI International
SRI International , founded as Stanford Research Institute, is one of the world's largest contract research institutes. Based in Menlo Park, California, the trustees of Stanford University established it in 1946 as a center of innovation to support economic development in the region. It was later...

 researcher Douglas Engelbart
Douglas Engelbart
Douglas Carl Engelbart is an American inventor, and an early computer and internet pioneer. He is best known for his work on the challenges of human-computer interaction, resulting in the invention of the computer mouse, and the development of hypertext, networked computers, and precursors to GUIs...

 in 1968 gave a preview of what would become the staples of daily working life in the 21st century - e-mail, hypertext, word processing, video conferencing, and the mouse. The demonstration required technical support staff and a mainframe time-sharing computer that were far too costly for individual business use at the time.

By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system
LINC
The LINC was a 12-bit, 2048-word computer. The LINC can be considered the first minicomputer and a forerunner to the personal computer....

 in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person.

In the 1970s Hewlett Packard introduced fully BASIC
BASIC
BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....

 programmable computers that fit entirely on top of a desk, including a keyboard, a small one-line display and printer. The Xerox Alto
Xerox Alto
The Xerox Alto was one of the first computers designed for individual use , making it arguably what is now called a personal computer. It was developed at Xerox PARC in 1973...

, developed in 1973 at Xerox's
Xerox
Xerox Corporation is an American multinational document management corporation that produced and sells a range of color and black-and-white printers, multifunction systems, photo copiers, digital production printing presses, and related consulting services and supplies...

 Palo Alto Research Center (PARC), had a graphical operating system (GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...

) that later served as inspiration for Apple Computer's Macintosh
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...

, and Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

's Windows operating system. The Wang 2200
Wang 2200
Wang 2200, appeared in May 1973, was Wang Laboratories' first minicomputer that could perform data processing in a common computer language. Unlike some other desktop computers, such as the HP 9830, it had a cathode ray tube in a cabinet that also included an integrated computer controlled...

 of 1973 had a full-size cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 (CRT) and cassette tape storage. The IBM 5100
IBM 5100
The IBM 5100 Portable Computer was a portable computer introduced in September 1975, six years before the IBM PC. It was the evolution of a prototype called the SCAMP that was developed at the IBM Palo Alto Scientific Center in 1973. In January 1978 IBM announced the IBM 5110, its larger cousin,...

 in 1975 had a small CRT display and could be programmed in BASIC and APL. These were generally expensive specialized computers sold for business or scientific uses. The introduction of the microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

, a single chip
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

 with all the circuitry that formerly occupied large cabinets, led to the proliferation of personal computers after 1975.

Early personal computers — generally called microcomputers — were sold often in kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done with toggle switches to enter instructions, and output was provided by front panel lamps. Practical use required adding peripherals such as keyboards, computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

s, disk drives, and printers. Micral
MICRAL
According to the Computer History Museum, the Micral N, produced by the French company R2E, was the earliest commercial, non-kit personal computer based on a microprocessor...

 N was the earliest commercial, non-kit microcomputer based on a microprocessor, the Intel 8008. It was built starting in 1972 and about 90,000 units were sold. In 1976 Steve Jobs
Steve Jobs
Steven Paul Jobs was an American businessman and inventor widely recognized as a charismatic pioneer of the personal computer revolution. He was co-founder, chairman, and chief executive officer of Apple Inc...

 and Steve Wozniak
Steve Wozniak
Stephen Gary "Woz" Wozniak is an American computer engineer and programmer who founded Apple Computer, Co. with Steve Jobs and Ronald Wayne...

 sold the Apple I computer
Apple I
The original Apple Computer, also known retroactively as the Apple I, or Apple-1, is a personal computer released by the Apple Computer Company in 1976. They were designed and hand-built by Steve Wozniak. Wozniak's friend Steve Jobs had the idea of selling the computer...

 circuit board, which was fully prepared and contained about 30 chips. The first successfully mass marketed personal computer was the Commodore PET
Commodore PET
The Commodore PET was a home/personal computer produced from 1977 by Commodore International...

 introduced in January 1977. It was soon followed by the Apple II
Apple II series
The Apple II series is a set of 8-bit home computers, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977 with the original Apple II...

 (usually referred to as the "Apple ][") in June 1977, and the TRS-80 from Radio Shack in November 1977. Mass-market ready-assembled computers allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware.

Through the late 1970s and into the 1980s, computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...

s were further developed for household use, with software for personal productivity, programming and games. One such machine, the Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...

, totaled 17 million units sold, making it the best-selling single personal computer model of all time. Somewhat larger and more expensive systems (although still low-cost compared with minicomputer
Minicomputer
A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...

s and mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

s) were aimed at office and small business use. Workstation
Workstation
A workstation is a high-end microcomputer 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...

s are characterized by high-performance processors and graphics displays, with large local disk storage, networking capability, and running under a multitasking operating system.
Eventually, due to the influence of the IBM PC 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 personal computers used at home.

In 1982 "The Computer" was named Machine of the Year by Time Magazine
Time (magazine)
Time is an American news magazine. A European edition is published from London. Time Europe covers the Middle East, Africa and, since 2003, Latin America. An Asian edition is based in Hong Kong...

.

Market and sales




In 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 from the mid-1970s up to this time. Of the latter figure, 75 percent were professional or work related, while the rest were sold for personal or home use. About 81.5 percent of personal computers shipped had been desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

s, 16.4 percent laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s and 2.1 percent server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

s. The United States had received 38.8 percent (394 million) of the computers shipped, Europe 25 percent and 11.7 percent had gone to the 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
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...

 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 350.9 million units in 2010,
308.3 million units in 2009
and 302.2 million units in 2008.
The shipments were 264 million units in the year 2007, according to iSuppli, up 11.2 percent from 239 million in 2006. In 2004, the global shipments were 183 million units, an 11.6 percent increase over 2003. In 2003, 152.6 million computers were shipped, at an estimated value of $175 billion. In 2002, 136.7 million PCs were shipped, at an estimated value of $175 billion. In 2000, 140.2 million personal computers were shipped, at an estimated value of $226 billion. 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. In 1999, Asia had 14.1 million units shipped.

For 2011, global PC shipments are expected to reach 364 million units, a 3.8% growth comparing to 2010.

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
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...

 and Japan accounted for 58 percent of the worldwide installed PCs. The emerging markets were expected to double their installed PCs by 2012 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.

Based on IDC data for Q2 2011, for the first time China surpassed US in PC shipments by 18.5 million and 17.7 million respectively. It is reflects the rising of emerging markets as well as the relative stagnation of mature regions.

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 the One Laptop per Child foundation and its low-cost XO-1
OLPC XO-1
The XO-1, previously known as the $100 Laptop, Children's Machine, and 2B1, is an inexpensive subnotebook computer intended to be distributed to children in developing countries around the world, to provide them with access to knowledge, and opportunities to "explore, experiment and express...

 laptop, the computing industry started to pursue the price too. Although introduced only one year earlier, there were 14 million netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

s sold in 2008. 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.

Deloitte consulting firm predicts that in 2011 smartphones and tablet computers as computing devices will surpass the PCs sales. Pc era is far from over as PCs will remain the main computing platform.

Average selling price


Selling prices of personal computers, unlike other consumer commodities, steadily declined due to lower costs of production and manufacture. Capabilities of the computers also increased. In 1975, an Altair kit sold for only around US $400, but required customers to solder components into circuit boards; peripherals required to interact with the system in alphanumeric form instead of blinking lights would add another $2000, and the resultant system was only of use to hobbyists.

At their introduction in 1981, the US $1,795 price of the Osborne 1
Osborne 1
The Osborne 1 was the first commercially successful portable microcomputer, released on April 3, 1981 by Osborne Computer Corporation. It weighed 10.7 kg , cost USD$ 1795, and ran the then-popular CP/M 2.2 operating system...

 and its competitor Kaypro
Kaypro
Kaypro Corporation, commonly called Kaypro, was an American home/personal computer manufacturer of the 1980s. The company was founded by Non-Linear Systems to develop computers to compete with the then-popular Osborne 1 portable microcomputer...

 was considered an attractive price point; these systems had text-only displays and only floppy disks for storage. By 1982, Michael Dell
Michael Dell
Michael Saul Dell is an American business magnate and the founder, chairman and chief executive officer of Dell Inc. He is the 44th richest person in the world, with a net worth of US$14.6 billion in 2011, based primarily on the 243.35 million shares of Dell stock worth $3.5 billion that he owns,...

 observed that a personal computer system selling at retail for about $3,000 US was made of components that cost the dealer about $600; typical gross margin on a computer unit was around $1,000. The total value of personal computer purchases in the US in 1983 was about $4 billion, comparable to total sales of pet food. By late 1998, the average selling price of personal computer systems in the United States had dropped below $1000.

For Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 systems, the average selling price
Average Selling Price
The average sales price of goods or commodities is the average price at which a particular product or commodity is sold across channels or markets. The term is especially used in the retail sector and technology distribution....

 (ASP) showed a decline in 2008/2009, possibly due to low-cost netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

s, drawing $569 for desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

s and $689 for laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s 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. According to research firm NPD, the average selling price of all Windows portable PCs has fallen from $659 in October 2008 to $519 in October 2009.

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
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...

 and run multi-user operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s. Workstations are used for tasks such as computer-aided design
Computer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...

, drafting and modeling, computation-intensive scientific and engineering calculations, image processing, architectural
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

 modeling, and computer graphics
Computer graphics
Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....

 for animation and motion picture visual effects.

Desktop computer




Prior to the wide spread of PCs a computer that could fit on a desk
Desk
A desk is a furniture form and a class of table often used in a work or office setting for reading or writing on or using a computer. Desks often have one or more drawers to store office supplies and papers. Unlike a regular table, usually only one side of a desk is suitable to sit on . Not all...

 was considered remarkably small. Today the phrase usually indicates a particular style of computer case
Computer case
A computer case is the enclosure that contains most of the components of a computer...

. Desktop computers come in a variety of styles ranging from large vertical tower cases to small form factor
Small form factor
A small form factor is a computer form factor designed to minimize the volume of a desktop computer. For comparison purposes, the size of an SFF case is usually measured in litres. SFFs are available in a variety of sizes and shapes, including shoeboxes, cubes, and book-sized PCs...

 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.

Gaming Computer


Games have been on computers since 1962 when Spacewar! was released. Today Personal Computer Gaming or PC gaming is a very popular pastime. Gaming computers tend to also be about the looks of the case rather than just the specifications of the hardware. A gaming computer needs to be much more powerful than a PC that someone is using to do office work and to surf the internet. A Gaming Computer has to have a good graphics card so that it can process all the 3D models and shapes that are on the screen. In addition the Central processing unit
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 or CPU has to do more work to calculate game mechanics, figure out gravity, and assist with the graphics and process the sound. Most serious gamers prefer to build their own computer or rig. This is because they can get exactly what they want and the price is a lot cheaper. When building a ‘high end’ computer the price is generally over $1000 with the motherboard costing from $300-$800 and the processor costing around $400-$500 and graphics cards that can cost more than $600. Many people say this is expensive but it's comparable to a video game console such as an Xbox 360
Xbox 360
The Xbox 360 is the second video game console produced by Microsoft and the successor to the Xbox. The Xbox 360 competes with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generation of video game consoles...

 or a PlayStation 3
PlayStation 3
The is the third home video game console produced by Sony Computer Entertainment and the successor to the PlayStation 2 as part of the PlayStation series. The PlayStation 3 competes with Microsoft's Xbox 360 and Nintendo's Wii as part of the seventh generation of video game consoles...

 as proced when released. In addition, a computer can be used for much more than just gaming, and a $1000 computer will last at least 5 years. The choice of parts to build a computer are vast as many companies build different parts of the system.
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 often utilizes a touchscreen
Touchscreen
A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus...

 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, and many are built similarly to laptops.

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 netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

s (see below). The product line features the new Intel Atom
Intel Atom
Intel Atom is the brand name for a line of ultra-low-voltage x86 and x86-64 CPUs from Intel, designed in 45 nm CMOS and used mainly in netbooks, nettops, embedded application ranging from health care to advanced robotics and Mobile Internet devices...

 processor which specially enables them to consume less power and to be built into small enclosures.

Home theater PC



A home theater PC (HTPC) is a convergence device that combines the functions of a personal computer and a digital video recorder
Digital video recorder
A digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...

. It is connected to a television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 or a television-sized computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

 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 server
Media Server
A media server refers either to a dedicated computer appliance or to a specialized application software, ranging from an enterprise class machine providing video on demand, to, more commonly, a small personal computer or NAS for the home, dedicated for storing various digital media .-Purpose:By...

s. The general goal in a HTPC is usually to combine many or all components of a home theater
Home cinema
Home cinema, also commonly called home theater, are home entertainment set-ups that seek to reproduce a movie theater experience and mood with the help of video and audio equipment in a private home....

 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
MythTV
MythTV is a free and open source home entertainment application with a simplified "10-foot user interface" design for the living-room TV, and turns a computer with the necessary hardware into a network streaming digital video recorder, a digital multimedia home entertainment system, or home theater...

, Windows Media Center
Windows Media Center
Windows Media Center is a digital video recorder and media player developed by Microsoft. It is an application that allows users to view and record live television, as well as organize and play music and videos...

, GB-PVR
GB-PVR
GB-PVR is a PVR application, running on Microsoft Windows, whose main function is scheduling TV recordings and playing back live TV. This PVR also acts as a home media center with a digital video recorder, a radio station online tuner, a music and movie player, a library of images and other...

, SageTV
SageTV
SageTV Media Center was a proprietary, commercial DVR and HTPC software for Mac OS X, Windows and Linux. It requires that the host computer have a hardware based TV tuner card. The SageTV software has an integrated Electronic Programming Guide that is updated via the Internet...

, Famulent or LinuxMCE
LinuxMCE
LinuxMCE is a free and open source software platform with a 10-foot user interface designed to allow a computer to act as a home theater PC for the living-room TV, personal video recorder, and home automation system. It allows control of everything in the home, from lighting and climate to...

.

Laptop



A laptop computer or simply laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

, also called a notebook computer, is a small personal computer designed for portability. Usually all of the interface hardware needed to operate the laptop, such as USB ports (previously parallel
Parallel port
A parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...

 and serial port
Serial port
In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...

s), graphics card, sound channel, etc., are built in to a single unit. Laptops contain high capacity batteries
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

 that can power the device for extensive periods of time, enhancing portability. Once the battery charge is depleted, it will have to be recharged through a power 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 sometimes, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Internal upgrades are either not manufacturer recommended, can damage the laptop if done with poor care or knowledge, or in some cases impossible, making the desktop PC more modular. Some internal upgrades, such as memory and hard disks upgrades are often easy, a display or keyboard upgrade is usually impossible. The laptop has the same access as the desktop to the wide variety of devices, such as external displays, mice, cameras, storage devices and keyboards, which may be attached externally through USB ports and other less common ports such as external video.

A subtype of notebooks, called subnotebook
Subnotebook
A subnotebook is a class of laptop computers that are smaller and lighter than a typical laptop....

s, 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 PC
Ultra-Mobile PC
An ultra-mobile PC is a small form factor version of a pen computer, a class of laptop whose specifications were launched by Microsoft and Intel in spring 2006. Sony had already made a first attempt in this direction in 2004 with its Vaio U series, which was however only sold in Asia...

s (UMPC) are usually considered subnotebooks, or more specifically, subnotebook Tablet PC
Tablet computer
A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...

s (see below). Netbook
Netbook
Netbooks are a category of small, lightweight, legacy-free, and inexpensive laptop computers.At their inception in late 2007 as smaller notebooks optimized for low weight and low cost — netbooks omitted certain features , featured smaller screens and keyboards, and offered reduced computing...

s are sometimes considered in this category, though they are sometimes separated in a category of their own (see below).
Desktop replacement

A desktop replacement computer (DTR) is a personal computer that provides the full capabilities of a desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

 while remaining mobile
Mobile computing
Mobile computing is a form of human–computer interaction by which a computer is expected to be transported during normal usage. Mobile computing has three aspects: mobile communication, mobile hardware, and mobile software...

. They are often larger, bulkier laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s. Because of their increased size, this class of computer usually includes more powerful components and a larger display than generally used in smaller portable computers and can have a relatively limited battery capacity (or none at all). Some use a limited range of desktop components to provide better performance at the expense of battery life. These are sometimes called desknotes, a portmanteau of the words "desktop" and "notebook," though the term is also applied to desktop replacement computers in general.

Netbook




Netbooks (also called mini notebooks or subnotebook
Subnotebook
A subnotebook is a class of laptop computers that are smaller and lighter than a typical laptop....

s) are a rapidly evolving category of small, light and inexpensive laptop computer
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s suited for general computing and accessing web-based applications
Web application
A web application is an application that is accessed over a network such as the Internet or an intranet. The term may also mean a computer software application that is coded in a browser-supported language and reliant on a common web browser to render the application executable.Web applications are...

; they are often marketed as "companion devices," that is, to augment a user's other computer access. Walt Mossberg called them a "relatively new category of small, light, minimalist and cheap laptops." By August 2009, CNET
CNET
CNET is a tech media website that publishes news articles, blogs, and podcasts on technology and consumer electronics. Originally founded in 1994 by Halsey Minor and Shelby Bonnie, it was the flagship brand of CNET Networks and became a brand of CBS Interactive through CNET Networks' acquisition...

 called netbooks "nothing more than smaller, cheaper notebooks.".

Initially, their primary defining characteristic was the lack of an optical disc
Optical disc
In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...

 drive, requiring it to be a separate and external device. This has become less important as flash memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...

 devices have gradually increased in capacity, replacing the writable optical disc (e.g. CD-RW
CD-RW
A CD-RW is a rewritable optical disc. It was introduced in 1997, and was known as "CD-Writable" during development. It was preceded by the CD-MO, which was never commercially released....

, DVD-RW
DVD-RW
A DVD-RW disc is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. The smaller Mini DVD-RW holds 1.46 GB, with a diameter of 8 cm.The primary advantage of DVD-RW over...

) as a transportable storage medium.

At their inception in late 2007 — as smaller notebooks optimized for low weight and low cost — netbooks omitted key features (e.g., the optical drive), featured smaller screens and keyboards, and offered reduced specification and computing power. Over the course of their evolution, netbooks have ranged in size from below 5 in to over 13 in, and from . Often significantly less expensive than other laptop
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

s, by mid-2009, netbooks had been offered to users "free of charge", with an extended service contract purchase of a cellular data plan.

In the short period since their appearance, netbooks have grown in size and features, now converging with new smaller, lighter notebooks. By mid 2009, CNET noted "the specs are so similar that the average shopper would likely be confused as to why one is better than the other," noting "the only conclusion is that there really is no distinction between the devices."

Tablet PC



A tablet PC is a notebook
Laptop
A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

 or slate-shaped mobile computer. Its touchscreen
Touchscreen
A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus...

 or graphics tablet/screen hybrid technology allows the user to operate the computer with a stylus
Stylus (computing)
In computing, a stylus is a small pen-shaped instrument that is used to input commands to a computer screen, mobile device or graphics tablet...

 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.

Ultra-mobile PC




The ultra-mobile PC (UMPC) is a specification for a small form factor
Small form factor
A small form factor is a computer form factor designed to minimize the volume of a desktop computer. For comparison purposes, the size of an SFF case is usually measured in litres. SFFs are available in a variety of sizes and shapes, including shoeboxes, cubes, and book-sized PCs...

 of tablet PC
Tablet computer
A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...

s. It was developed as a joint development exercise by Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

, Intel, and Samsung
Samsung
The Samsung Group is a South Korean multinational conglomerate corporation headquartered in Samsung Town, Seoul, South Korea...

, among others. Current UMPCs typically feature the Windows XP, Windows Vista, Windows 7, or Linux operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 and low-voltage Intel Atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

 or VIA C7-M processors.

Pocket PC




A pocket PC is a hardware specification for a handheld-sized computer (personal digital assistant
Personal digital assistant
A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...

) that runs the Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

 Windows Mobile
Windows Mobile
Windows Mobile is a mobile operating system developed by Microsoft that was used in smartphones and Pocket PCs, but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone, which does not run Windows Mobile software.Windows Mobile is...

 operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

. It may have the capability to run an alternative operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 like NetBSD
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...

 or Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

. It has many of the capabilities of modern desktop PCs
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...

.

Currently there are tens of thousands of applications for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware
Freeware
Freeware is computer software that is available for use at no cost or for an optional fee, but usually with one or more restricted usage rights. Freeware is in contrast to commercial software, which is typically sold for profit, but might be distributed for a business or commercial purpose in the...

. Some of these devices also include mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...

 features and thus actually represent a smartphone
Smartphone
A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...

. Microsoft compliant Pocket PCs can also be used with many other add-ons like GPS receivers
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

, barcode
Barcode
A barcode is an optical machine-readable representation of data, which shows data about the object to which it attaches. Originally barcodes represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or 1 dimensional . Later they evolved into rectangles,...

 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.

Hardware



Mass-market consumer computers use highly standardized components and so are simple for an end user to assemble into a working system. A typical desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

 consists of a computer case
Computer case
A computer case is the enclosure that contains most of the components of a computer...

 which holds the power supply, motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...

, hard disk and often an optical disc drive. External devices such as a computer monitor or visual display unit, keyboard
Computer keyboard
In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

, and a pointing device
Pointing device
A pointing device is an input interface that allows a user to input spatial data to a computer...

 are usually found in a personal computer.

The motherboard connects all processor, memory and peripheral devices together. The RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...

, graphics card and processor are mounted directly onto the motherboard. The central processing unit
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 microprocessor chip plugs into a socket
CPU socket
A CPU socket or CPU slot is a mechanical component that provides mechanical and electrical connections between a microprocessor and a printed circuit board . This allows the CPU to be replaced without soldering....

. Expansion memory plugs into memory sockets. Some motherboards have the video display adapter, sound and other peripherals integrated onto the motherboard. Others use expansion slots for graphics cards, network cards, or other I/O
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

 devices. Disk drives for mass storage are connected to the mother board with a cable, and to the power supply through another cable. Usually disk drives are mounted in the same case as the motherboard; formerly, expansion chassis were made for additional disk storage.

The graphics and sound card can have a break out box to keep the analog parts away from the electromagnetic radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...

 inside the computer case. For really large amounts of data, a tape drive
Tape drive
A tape drive is a data storage device that reads and performs digital recording, writes data on a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and long archival stability.A tape drive provides...

 can be used or (extra) hard disks can be put together in an external case.

The keyboard and the mouse are external devices plugged into the computer through connectors on an I/O panel on the back of the computer. The monitor is also connected to the I/O panel, either through an onboard port on the motherboard, or a port on the graphics card.

The hardware
Computer hardware
Personal computer hardware are component devices which are typically installed into or peripheral to a computer case to create a personal computer upon which system software is installed including a firmware interface such as a BIOS and an operating system which supports application software that...

 capabilities of personal computers can sometimes be extended by the addition of expansion card
Expansion card
The expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus.One edge of the expansion card holds the contacts that fit exactly into the slot...

s connected via an expansion bus
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...

. Some standard peripheral buses often used for adding expansion cards in personal computers as of 2005 are PCI
Peripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...

, AGP
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...

 (a high-speed PCI bus dedicated to graphics adapters), and PCI Express
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...

. Most personal computers as of 2005 have multiple physical PCI
Peripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...

 expansion slots. Many also include an AGP bus and expansion slot or a PCI Express bus and one or more expansion slots, but few PCs contain both buses.

Toxic chemicals, such as lead and mercury, are found in certain pieces of PC hardware.
Lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

 is found in the Cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 (CRT), which is located inside the monitor, as well as in the Printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...

. While daily PC users are not exposed to these toxic elements, danger arises in computer recycling
Computer recycling
Computer recycling or electronic recycling is the recycling or reuse of computers or other electronics. It includes both finding another use for materials , and having systems dismantled in a manner that allows for the safe extraction of the constituent materials for reuse in other...

, and thus stems the controversy of electronic waste
Electronic waste
Electronic waste, e-waste, e-scrap, or Waste Electrical and Electronic Equipment describes discarded electrical or electronic devices. There is a lack of consensus as to whether the term should apply to resale, reuse, and refurbishing industries, or only to product that cannot be used for its...

 (e-Waste). The process of computer recycling involves workers responsible for manually breaking down computers, which leads to inevitable exposure to these toxic chemicals and serious health issues. Lead is known to cause damage to the central nervous system, kidneys, and slow down child brain development.
Mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

, another toxic element found in PCs, is located in the screen's fluorescent lamp
Fluorescent lamp
A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...

, laser light generators in the optical disk drive, and in mercury batteries in the circuit board and expansion cards. Even the smallest amount of mercury, if it is inhaled or digested can cause serious brain damage.
Other chemicals found in PCs are cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...

, chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...

, Polyvinyl chloride
Polyvinyl chloride
Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

 (PVC), and barium
Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...

, which are also found in the motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...

 and other crucial pieces of the computer.
In each individual computer, about 17% of the computer is lead, copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

, mercury, and cadmium, 23% is plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 (which usually gets burned and causes extreme air pollution), and 14% is Aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 and 20% is Iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 (the last two do not cause extreme health risks, however they are natural elements and do not decompose, which means they continue to take up space unless they are recycled into new computers). Although there is not a huge amount of these hazardous chemicals in each individual computer, even the smallest amount of lead or mercury can ruin a community’s drinking water, or cause serious brain damage.

Computer case




A computer case is the enclosure that contains the main components of a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

. Cases are usually constructed from steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 or aluminum, although other materials such as wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 and plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 have been used. Cases can come in many different sizes, or form factors. The size and shape of a computer case is usually determined by the form factor of the motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...

 that it is designed to accommodate, since this is the largest and most central component of most computers. Consequently, personal computer form factors typically specify only the internal dimensions and layout of the case. Form factors for rack-mounted and blade
Blade server
A blade server is a stripped down server computer with a modular design optimized to minimize the use of physical space and energy. Whereas a standard rack-mount server can function with a power cord and network cable, blade servers have many components removed to save space, minimize power...

 servers
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

 may include precise external dimensions as well, since these cases must themselves fit in specific enclosures.

Currently, the most popular form factor for desktop computers is ATX
ATX
ATX is a motherboard form factor specification developed by Intel in 1995 to improve on previous de facto standards like the AT form factor. It was the first big change in computer case, motherboard, and power supply design in many years, improving standardization and interchangeability of parts...

, although microATX
MicroATX
microATX, also known as µATX is a standard for motherboards that was introduced in December 1997. The maximum size of a microATX motherboard is 244 mm × 244 mm , but some microATX boards can be as small as 171.45 mm × 171.45 mm...

 and small form factor
Small form factor
A small form factor is a computer form factor designed to minimize the volume of a desktop computer. For comparison purposes, the size of an SFF case is usually measured in litres. SFFs are available in a variety of sizes and shapes, including shoeboxes, cubes, and book-sized PCs...

s have become very popular for a variety of uses. Companies like Shuttle Inc.
Shuttle Inc.
Shuttle is a Taiwan-based manufacturer of motherboards, barebone computers, complete PC systems, and monitors. Throughout the last 10 years, Shuttle has been one of the world's top 10 motherboard manufacturers, and gained fame in 2001 with the introduction of the Shuttle SV24, one of the world's...

 and AOpen
Acer (company)
Acer Incorporated is a multinational information technology and electronics corporation headquartered in Xizhi, New Taipei City, Taiwan. Acer's products include desktop and laptop PCs, tablet computers, servers, storage devices, displays, smartphones and peripherals...

 have popularized small cases, for which FlexATX
FlexATX
FlexATX is a motherboard form factor derived from ATX. The specification was released in 1999 by Intel as an addendum to the microATX specification...

 is the most common motherboard size.

Power supply unit




The power supply unit converts general purpose electric current from the mains
Mains electricity
Mains is the general-purpose alternating current electric power supply. In the US, electric power is referred to by several names including household power, household electricity, powerline, domestic power, wall power, line power, AC power, city power, street power, and grid power...

 to direct current
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

 for the other components of the computer.

Processor




The central processing unit, or CPU, is that part of a computer which executes software program
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

 instructions. In older computers this circuitry was formerly on several printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...

s, but in PCs is a single integrated circuit. Nearly all PCs contain a type of CPU known as a microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

. The microprocessor often plugs into the motherboard using one of many different types of sockets. IBM PC compatible
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...

 computers use an x86-compatible processor, usually made by Intel, AMD, VIA Technologies
VIA Technologies
VIA Technologies is a Taiwanese manufacturer of integrated circuits, mainly motherboard chipsets, CPUs, and memory, and is part of the Formosa Plastics Group. It is the world's largest independent manufacturer of motherboard chipsets...

 or Transmeta
Transmeta
Transmeta Corporation was a US-based corporation that licensed low power semiconductor intellectual property. Transmeta originally produced very long instruction word code morphing microprocessors, with a focus on reducing power consumption in electronic devices. It was founded in 1995 by Bob...

. Apple Macintosh computers were initially built with the Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...

 680x0 family of processors, then switched to the PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...

 series (a RISC architecture jointly developed by Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...

, IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

 and Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...

), but as of 2006, Apple switched again, this time to x86-compatible processors by Intel. Modern CPUs are equipped with a fan
Computer fan
A computer fan is any fan inside, or attached to, a computer case used for cooling purposes, and may refer to fans that draw cooler air into the case from the outside, expel warm air from inside, or move air across a heatsink to cool a particular component...

 attached via heat sink
Heat sink
A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...

.

Motherboard




The motherboard, also referred to as systemboard or mainboard, is the primary circuit board within a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry - usually integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

s (ICs) - providing the interface between the CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 memory and input/output peripheral circuits, main memory, and facilities for initial setup of the computer immediately after power-on (often called boot firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...

 or, in IBM PC compatible computers, a BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....

). In many portable and embedded personal computers, the motherboard houses nearly all of the PC's core components. Often a motherboard will also contain one or more peripheral buses and physical connectors for expansion purposes. Sometimes a secondary daughter board is connected to the motherboard to provide further expandability or to satisfy space constraints.

Main memory




A PC's main memory is fast storage that is directly accessible by the CPU, and is used to store the currently executing program and immediately needed data. PCs use semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...

 random access memory (RAM) of various kinds such as DRAM
Dynamic random access memory
Dynamic random-access memory is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1...

, SDRAM or SRAM
Static random access memory
Static random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...

 as their primary storage. Which exact kind depends on cost/performance issues at any particular time. Main memory is much faster than mass storage devices like hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

s or optical disc
Optical disc
In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...

s, but is usually volatile
Volatile memory
Volatile memory, also known as volatile storage, is computer memory that requires power to maintain the stored information, unlike non-volatile memory which does not require a maintained power supply...

, meaning it does not retain its contents (instructions or data) in the absence of power, and is much more expensive for a given capacity than is most mass storage. Main memory is generally not suitable for long-term or archival data storage.

Hard disk




Mass storage devices store programs and data even when the power is off; they do require power to perform read and write functions during usage. Although flash memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...

 has dropped in cost, the prevailing form of mass storage in personal computers is still the hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

.

The disk drives use a sealed head/disk assembly (HDA) which was first introduced by IBM's "Winchester" disk system. The use of a sealed assembly allowed the use of positive air pressure to drive out particles from the surface of the disk, which improves reliability.

If the mass storage controller provides for expandability, a PC may also be upgraded by the addition of extra hard disk or optical disc drives. For example, BD-ROMs, DVD-RW
DVD-RW
A DVD-RW disc is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. The smaller Mini DVD-RW holds 1.46 GB, with a diameter of 8 cm.The primary advantage of DVD-RW over...

s, and various optical disc recorders may all be added by the user to certain PCs. Standard internal storage device connection interfaces are PATA, Serial ATA
Serial ATA
Serial ATA is a computer bus interface for connecting host bus adapters to mass storage devices such as hard disk drives and optical drives...

, SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...


Video card



The video card
Video card
A video card, Graphics Card, or Graphics adapter is an expansion card which generates output images to a display. Most video cards offer various functions such as accelerated rendering of 3D scenes and 2D graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors...

 - otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

, and is an essential part of the modern computer. On older models, and today on budget models, graphics circuitry tended to be integrated with the motherboard but, for modern flexible machines, they are supplied in PCI
Peripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...

, AGP
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...

, or PCI Express
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...

 format.

When the IBM PC was introduced, most existing business-oriented personal computers used text-only display adapters and had no graphics capability. Home computers at that time had graphics compatible with television signals, but with low resolution by modern standards owing to the limited memory available to the eight-bit processors available at the time.

Visual display unit




A visual display unit (or monitor) is a piece of electrical equipment
Electrical equipment
Electrical equipment includes any machine powered by electricity. They usually consists of an enclosure, a variety of electrical components, and often a power switch...

, usually separate from the computer case, which displays viewable image
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...

s generated by a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 without producing a permanent record. The word "monitor" is used in other contexts; in particular in television broadcasting, where a television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 picture is displayed to a high standard on a broadcast reference monitor. A computer display device is usually either a cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 or some form of flat panel such as a TFT LCD
TFT LCD
Thin film transistor liquid crystal display is a variant of liquid crystal display which uses thin-film transistor technology to improve image quality . TFT LCD is one type of Active matrix LCD, though all LCD-screens are based on TFT active matrix addressing...

. The monitor comprises the display device, circuitry
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...

 to generate a picture from electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

 signals
Signal (electrical engineering)
In the fields of communications, signal processing, and in electrical engineering more generally, a signal is any time-varying or spatial-varying quantity....

 sent by the computer, and an enclosure
Enclosure (electrical)
An electrical enclosure is a cabinet for electrical or electronic equipment to mount switches, knobs and displays and to prevent electrical shock to equipment users and protect the contents from the environment...

 or case. Within the computer, either as an integral part or a plugged-in Expansion card
Expansion card
The expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus.One edge of the expansion card holds the contacts that fit exactly into the slot...

, there is circuitry to convert internal data
Data (computing)
In computer science, data is information in a form suitable for use with a computer. Data is often distinguished from programs. A program is a sequence of instructions that detail a task for the computer to perform...

 to a format compatible with a monitor. The images from monitors originally contained only text, but as Graphical user interface
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

s emerged and became common, they began to display more images and multimedia content.

Keyboard




In computing, a keyboard
Keyboard (computing)
In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...

 is an arrangement of buttons that each correspond to a function, letter, or number. They are the primary devices of inputting text. In most cases, they contain an array of keys specifically organized with the corresponding letters, numbers, and functions printed or engraved on the button. They are generally designed around an operators language, and many different versions for different languages exist.
In English, the most common layout is the QWERTY
QWERTY
QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...

 layout, which was originally used in typewriter
Typewriter
A typewriter is a mechanical or electromechanical device with keys that, when pressed, cause characters to be printed on a medium, usually paper. Typically one character is printed per keypress, and the machine prints the characters by making ink impressions of type elements similar to the pieces...

s. They have evolved over time, and have been modified for use in computers with the addition of function keys, number keys, arrow keys, and OS specific keys. Often, specific functions can be achieved by pressing multiple keys at once or in succession, such as inputting characters with accents or opening a task manager. Programs use keyboard shortcuts very differently and all use different keyboard shortcuts for different program specific operations, such as refreshing a web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...

 in a web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

 or selecting all text in a word processor.

Mouse


A Mouse
Mouse (computing)
In computing, a mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons...

 on a computer is a small, slideable device that users hold and slide around to point at, click on, and sometimes drag objects on screen in a graphical user interface using a pointer on screen. Almost all Personal Computers have mice. It may be plugged into a computer's rear mouse socket, or as a USB device, or, more recently, may be connected wirelessly via a USB antenna or Bluetooth antenna. In the past, they had a single button that users could press down on the device to "click" on whatever the pointer on the screen was hovering over. Now, however, many Mice have two or three buttons(possibly more); a "right click" function button on the mouse, which performs a secondary action on a selected object, and a scroll wheel, which users can rotate using their fingers to "scroll" up or down. The scroll wheel can also be pressed down, and therefore be used as a third button. Some mouse wheels may be tilted from side to side to allow sideways scrolling. Different programs make use of these functions differently, and may scroll horizontally by default with the scroll wheel, open different menus with different buttons, among others. These functions may be user defined through software utilities.

Mice traditionally detected movement and communicated with the computer with an internal "mouse ball"; and used optical encoders to detect rotation of the ball and tell the computer where the mouse has moved. However, these systems were subject to low durability, accuracy and required internal cleaning. Modern mice use optical technology to directly trace movement of the surface under the mouse and are much more accurate, durable and almost maintenance free. They work on a wider variety of surfaces and can even operate on walls, ceilings or other non-horizontal surfaces.

Other components



Mass storage
All computers require either fixed or removable storage for their operating system, programs and user generated material.

Formerly the 5¼ inch and 3½ inch floppy drive were the principal forms of removable storage for backup of user files and distribution of software.

As memory sizes increased, the capacity of the floppy did not keep pace; the Zip drive
Zip drive
The Zip drive is a medium-capacity removable disk storage system that was introduced by Iomega in late 1994. Originally, Zip disks launched with capacities of 100 MB, but later versions increased this to first 250 MB and then 750 MB....

 and other higher-capacity removable media were introduced but never became as prevalent as the floppy drive.

By the late 1990s the optical drive, in CD and later DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

 and Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...

, became the main method for software distribution, and writeable media provided backup and file interchange. Floppy drives have become uncommon in desktop personal computers since about 2000, and were dropped from many laptop systems even earlier.The NeXT
NeXT
Next, Inc. was an American computer company headquartered in Redwood City, California, that developed and manufactured a series of computer workstations intended for the higher education and business markets...

 computer introduced in 1988 did not include a floppy drive, which at the time was unusual.


Early home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...

s used compact audio cassettes
Compact Cassette
The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. It was designed originally for dictation, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel...

 for file storage; these were at the time a very low cost storage solution, but were displaced by floppy disk drives when manufacturing costs dropped, by the mid 1980s.

A second generation of tape recorders was provided when Videocassette recorder
Videocassette recorder
The videocassette recorder , is a type of electro-mechanical device that uses removable videocassettes that contain magnetic tape for recording analog audio and analog video from broadcast television so that the images and sound can be played back at a more convenient time...

s were pressed into service as backup media for larger disk drives. All these systems were less reliable and slower than purpose-built magnetic tape drives. Such tape drives were uncommon in consumer-type personal computers but were a necessity in business or industrial use.

Interchange of data such as photographs from digital cameras is greatly expedited by installation of a card reader
Card reader
A card reader is a data input device that reads data from a card-shaped storage medium. Historically, paper or cardboard punched cards were used throughout the first several decades of the computer industry to store information and programs for computer system, and were read by punched card readers...

, which often is compatible with several forms of flash memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...

. It is usually faster and more convenient to move large amounts of data by removing the card from the mobile device, instead of communicating with the mobile device through a USB interface.

A USB flash drive
USB flash drive
A flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...

 today performs much of the data transfer and backup functions formerly done with floppy drives, Zip disks and other devices. Main-stream current operating systems for personal computers provide standard support for flash drives, allowing interchange even between computers using different processors and operating systems. The compact size and lack of moving parts or dirt-sensitive media, combined with low cost for high capacity, have made flash drives a popular and useful accessory for any personal computer user.

The operating system (e.g.: Microsoft Windows, Mac OS, Linux or many others) can be located on any storage, but typically it is on a hard disks. A Live CD
Live CD
A live CD, live DVD, or live disc is a CD or DVD containing a bootable computer operating system. Live CDs are unique in that they have the ability to run a complete, modern operating system on a computer lacking mutable secondary storage, such as a hard disk drive...

 is the running of a OS directly from a CD. While this is slow compared to storing the OS on a hard drive, it is typically used for installation of operating systems, demonstrations, system recovery, or other special purposes. Large flash memory is currently more expensive than hard drives of similar size (as of mid-2008) but are starting to appear in laptop computers because of their low weight, small size and low power requirements.

Computer communications
  • Internal modem card
    Softmodem
    A Softmodem, or software modem, is a modem with minimal hardware capacities, designed to use a host computer's resources to perform most of the tasks performed by dedicated hardware in a traditional modem.A Softmodem is also referred to as a Winmodem because the first commercially available...

  • Modem
    Modem
    A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...

  • Network adapter card
    Network card
    A network interface controller is a computer hardware component that connects a computer to a computer network....

  • Router


Common peripheral
Peripheral
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....

s and adapter cards
  • Headset
    Headset (telephone/computer)
    A headset is headphones combined with a microphone, or one headphone with a microphone. Headsets provide the equivalent functionality of a telephone handset with hands-free operation. Headsets typically have only one speaker like a telephone, but also come with speakers for both ears...

  • Joystick
    Joystick
    A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...

  • Microphone
    Microphone
    A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...

  • Printer
    Computer printer
    In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...

  • Scanner
    Image scanner
    In computing, an image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop scanner where the document is placed on a glass...

  • Sound adapter card
    Sound card
    A sound card is an internal computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware...

     as a separate card rather than located on the motherboard
  • Speaker
    Loudspeaker
    A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...

    s
  • Webcam
    Webcam
    A webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, or Wi-Fi.Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera...


Software




Computer software is a general term used to describe a collection of computer program
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

s, procedures and documentation that perform some tasks on a computer system.
The term includes application software
Application software
Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...

 such as word processor
Word processor
A word processor is a computer application used for the production of any sort of printable material....

s which perform productive tasks for users, system software
System software
System software is computer software designed to operate the computer hardware and to provide a platform for running application software.The most basic types of system software are:...

 such as operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s, which interface with hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....

 to provide the necessary services for application software, and middleware
Middleware
Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...

 which controls and co-ordinates distributed systems
Distributed computing
Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...

.

Software applications for word processing
Word processing
Word processing is the creation of documents using a word processor. It can also refer to advanced shorthand techniques, sometimes used in specialized contexts with a specially modified typewriter.-External links:...

, Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

 browsing, Internet fax
Internet fax
Internet fax uses the Internet to receive and send faxes.Internet faxing, "e-Fax" or "online faxing" is a general term which refers to sending a document facsimile using the Internet, rather than using only phone networks with a fax machine.Depending on the specific method/implementation ,...

ing, e-mail
E-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...

 and other digital messaging, multimedia
Multimedia
Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which use only rudimentary computer display such as text-only, or...

 playback, computer game play and computer programming
Computer programming
Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...

 are common. The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in programming nor even able to write programs for the computer. Therefore, most software written primarily for personal computers tends to be designed with simplicity of use, or "user-friendliness
Usability
Usability is the ease of use and learnability of a human-made object. The object of use can be a software application, website, book, tool, machine, process, or anything a human interacts with. A usability study may be conducted as a primary job function by a usability analyst or as a secondary job...

" in mind. However, the software industry
Software industry
The software industry includes businesses involved in the development, maintenance and publication of computer software using any business model...

 continuously provide a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.

Operating system



An operating system (OS) manages computer resources and provides programmers with an interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

 used to access those resources. An operating system processes system data and user input, and responds by allocating and managing tasks and internal system resources as a service to users and programs of the system. An operating system performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

 devices, facilitating computer networking and managing files.

Common contemporary desktop OSs are Microsoft Windows, Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

, Linux, Solaris and FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...

. Windows, Mac, and Linux all have server and personal variants. With the exception of Microsoft Windows, the designs of each of the aforementioned OSs were inspired by, or directly inherited from, the Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 operating system. Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 was developed at Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...

 beginning in the late 1960s and spawned the development of numerous free and proprietary operating systems.

Microsoft Windows



Microsoft Windows is the collective brand name of several software operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s by Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...

 in response to the growing interest in graphical user interface
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

s (GUIs) generated by Apple's 1984 introduction of the Macintosh
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...

. The most recent client version of Windows is Windows 7 and Windows Server 2008 R2
Windows Server 2008 R2
Windows Server 2008 R2 is a server operating system produced by Microsoft. It was released to manufacturing on July 22, 2009 and launched on October 22, 2009. According to the Windows Server Team blog, the retail availability was September 14, 2009. It is built on Windows NT 6.1, the same core...

 which was available at retail on October 22, 2009.

Mac OS X



Mac OS X is a line of operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s developed, marketed, and sold by Apple Inc.. Mac OS X is the successor to the original Mac OS
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...

, which had been Apple's primary operating system since 1984. Mac OS X is a Unix-based graphical operating system. The most recent version of Mac OS X is Mac OS X Lion
Mac OS X Lion
Mac OS X Lion is the eighth and current major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers....

.

AmigaOS



AmigaOS is the default native operating system of the Amiga personal computer. It was developed first by Commodore International, and initially introduced in 1985 with the Amiga 1000. Early versions (1.0-3.9) run on the Motorola 68k series of 16-bit and 32-bit microprocessors, while the newer AmigaOS 4 runs only on PowerPC microprocessors.
On top of a preemptive multitasking kernel called Exec, it includes an abstraction of the Amiga's unique hardware, a disk operating system called AmigaDOS, a windowing system API called Intuition and a graphical user interface called Workbench. A command line interface called AmigaShell is also available and integrated into the system. The GUI and the CLI complement each other and share the same privileges.
The current holder of the Amiga intellectual properties is Amiga Inc. They oversaw the development of AmigaOS 4 but did not develop it themselves, contracting it instead to Hyperion Entertainment. On 20 December 2006, Amiga Inc terminated Hyperion's license to continue development of AmigaOS 4. However, in 30 September 2009, Hyperion was granted an exclusive, perpetual, worldwide right to AmigaOS 3.1 in order to use, develop, modify, commercialize, distribute and market AmigaOS 4.x and subsequent versions of AmigaOS (including AmigaOS 5).

Linux




Linux is a family of Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 computer operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s. Linux is one of the most prominent examples of free software
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 and open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 development: typically all underlying source code
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...

 can be freely modified, used, and redistributed by anyone. The name "Linux" comes from the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....

, started in 1991 by Linus Torvalds
Linus Torvalds
Linus Benedict Torvalds is a Finnish software engineer and hacker, best known for having initiated the development of the open source Linux kernel. He later became the chief architect of the Linux kernel, and now acts as the project's coordinator...

. The system's utilities
System utility
The system utility may be defined in terms of the satisfaction of the system stakeholders.- Actual Utility :The actual utility is the actual stakeholders' satisfaction....

 and libraries
Library (computer science)
In computer science, a library is a collection of resources used to develop software. These may include pre-written code and subroutines, classes, values or type specifications....

 usually come from the GNU
GNU
GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...

 operating system, announced in 1983 by Richard Stallman
Richard Stallman
Richard Matthew Stallman , often shortened to rms,"'Richard Stallman' is just my mundane name; you can call me 'rms'"|last= Stallman|first= Richard|date= N.D.|work=Richard Stallman's homepage...

. The GNU contribution is the basis for the alternative name
GNU/Linux naming controversy
The GNU/Linux naming controversy is a dispute among members of the free and open source software community over how to refer to the computer operating system commonly called Linux....

 GNU/Linux.

Known for its use in server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

s as part of the LAMP
LAMP (software bundle)
LAMP is an acronym for a solution stack of free, open source software, referring to the first letters of Linux , Apache HTTP Server, MySQL and PHP , principal components to build a viable general purpose web server.The GNU project is advocating people to use the term "GLAMP" since what is known as...

 application stack, Linux is supported by corporations such as Dell
Dell
Dell, Inc. is an American multinational information technology corporation based in 1 Dell Way, Round Rock, Texas, United States, that develops, sells and supports computers and related products and services. Bearing the name of its founder, Michael Dell, the company is one of the largest...

, Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

, IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

, Novell
Novell
Novell, Inc. is a multinational software and services company. It is a wholly owned subsidiary of The Attachmate Group. It specializes in network operating systems, such as Novell NetWare; systems management solutions, such as Novell ZENworks; and collaboration solutions, such as Novell Groupwise...

, Oracle Corporation
Oracle Corporation
Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

, Red Hat
Red Hat
Red Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....

, Canonical Ltd.
Canonical Ltd.
Canonical Ltd. is a private company founded by South African entrepreneur Mark Shuttleworth to market commercial support and related services for Ubuntu Linux and related projects. Canonical is registered in London and employs staff around the world...

 and Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

. It is used as an operating system for a wide variety of computer hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....

, including desktop computer
Desktop computer
A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

s, netbooks, supercomputers, video game systems, such as the PlayStation 3
PlayStation 3
The is the third home video game console produced by Sony Computer Entertainment and the successor to the PlayStation 2 as part of the PlayStation series. The PlayStation 3 competes with Microsoft's Xbox 360 and Nintendo's Wii as part of the seventh generation of video game consoles...

, several arcade games, and embedded devices such as mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...

s, portable media player
Portable media player
A portable media player or digital audio player, is a consumer electronics device that is capable of storing and playing digital media such as audio, images, video, documents, etc. the data is typically stored on a hard drive, microdrive, or flash memory. In contrast, analog portable audio...

s, routers, and stage lighting
Stage lighting
Modern stage lighting is a flexible tool in the production of theatre, dance, opera and other performance arts. Several different types of stage lighting instruments are used in the pursuit of the various principles or goals of lighting. Stage lighting has grown considerably in recent years...

 systems.

Applications



A computer user will apply application software to carry out a specific task. System software
System software
System software is computer software designed to operate the computer hardware and to provide a platform for running application software.The most basic types of system software are:...

 supports applications and provides common services such as memory management, network connectivity, or device drivers; all of which may be used by applications but which are not directly of interest to the end user. A simple, if imperfect analogy
Analogy
Analogy is a cognitive process of transferring information or meaning from a particular subject to another particular subject , and a linguistic expression corresponding to such a process...

 in the world of hardware would be the relationship of an electric light bulb (an application) to an electric power generation plant (a system). The power plant merely generates electricity, not itself of any real use until harnessed to an application like the electric light that performs a service that benefits the user.

Typical examples of software applications are word processor
Word processor
A word processor is a computer application used for the production of any sort of printable material....

s, spreadsheet
Spreadsheet
A spreadsheet is a computer application that simulates a paper accounting worksheet. It displays multiple cells usually in a two-dimensional matrix or grid consisting of rows and columns. Each cell contains alphanumeric text, numeric values or formulas...

s, and media players. Multiple applications bundled together as a package are sometimes referred to as an application suite. Microsoft Office
Microsoft Office
Microsoft Office is a non-free commercial office suite of inter-related desktop applications, servers and services for the Microsoft Windows and Mac OS X operating systems, introduced by Microsoft in August 1, 1989. Initially a marketing term for a bundled set of applications, the first version of...

 and OpenOffice.org
OpenOffice.org
OpenOffice.org, commonly known as OOo or OpenOffice, is an open-source application suite whose main components are for word processing, spreadsheets, presentations, graphics, and databases. OpenOffice is available for a number of different computer operating systems, is distributed as free software...

, which bundle together a word processor, a spreadsheet, and several other discrete applications, are typical examples. The separate applications in a suite usually have a user interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

 that has some commonality making it easier for the user to learn and use each application. And often they may have some capability to interact with each other in ways beneficial to the user. For example, a spreadsheet might be able to be embedded in a word processor document even though it had been created in the separate spreadsheet application.

End-user development tailors systems to meet the user's specific needs. User-written software include spreadsheet templates, word processor macros, scientific simulations, graphics and animation scripts. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is.

Disposal of


Personal Computers are recycled in different methods, but they can also become a large contributor to the 50 million tons of waste of discarded electronic goods that is being generated annually, according to the United Nations Environment Programme. In order to solve the issue of electronic waste
Electronic waste
Electronic waste, e-waste, e-scrap, or Waste Electrical and Electronic Equipment describes discarded electrical or electronic devices. There is a lack of consensus as to whether the term should apply to resale, reuse, and refurbishing industries, or only to product that cannot be used for its...

 affecting developing countries and the environment, an Extended producer responsibility
Extended producer responsibility
Extended producer responsibility is a strategy designed to promote the integration of environmental costs associated with goods throughout their life cycles into the market price of the products.- Definition :...

 act was implemented. Organizations, such as, the Silicon Valley Toxics Coalition
Silicon Valley Toxics Coalition
The Silicon Valley Toxics Coalition , is a San Jose, California based research and advocacy group that promotes safe environmental practices in the high tech industry...

, Basel Action Network
Basel Action Network
The Basel Action Network is an non-governmental charitable organization working to combat the export of toxic waste, toxic technology and toxic products from industrialized societies to developing countries. BAN operates globally but is based in Seattle, Washington, United States, with a partner...

, Toxics Link India, SCOPE, and Greenpeace
Greenpeace
Greenpeace is a non-governmental environmental organization with offices in over forty countries and with an international coordinating body in Amsterdam, The Netherlands...

 contribute to the strategy. The Silicon Valley Toxics Coalition
Silicon Valley Toxics Coalition
The Silicon Valley Toxics Coalition , is a San Jose, California based research and advocacy group that promotes safe environmental practices in the high tech industry...

 and BAN (Basel Action Network) teamed up with 32 electronic recyclers in the US and Canada to create an e-steward program due to the lack of national legislation an regulation for the exporting and importing of electronic waste. The creation of an e-steward program created another option for manufacturers and customers to dispose of their electronic waste properly. The Silicon Valley Toxics Coalition founded the Electronics TakeBack Coalition, which is a coalition that advocates for the production of environmentally friendly products. The TakeBack Coalition works with policy makers, recyclers, and smart businesses to get manufacturers to take full responsibility of their products. There are organizations opposing EPR, such as the Reason Foundation
Reason Foundation
The Reason Foundation is an American nonprofit think tank founded in 1978 that also publishes Reason magazine. Based in Los Angeles, Reason is self-described as nonpartisan and publishes a statement of values that can best be described as libertarian...

 opposes the EPR for two main reasons. The first reason is that the EPR relies on the idea that is the manufacturers pay for the harm they do to the environment, they will learn their lesson. The second reason is that the EPR assumes the current design practices are environmentally inefficient. The Reason Foundation claims that manufacturers are moving toward reduced material use and energy use instead.

See also


  • Computer virus
    Computer virus
    A computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability...

  • Desktop computer
    Desktop computer
    A desktop computer is a personal computer in a form intended for regular use at a single location, as opposed to a mobile laptop or portable computer. Early desktop computers are designed to lay flat on the desk, while modern towers stand upright...

  • Desktop replacement computer
    Desktop replacement computer
    A desktop replacement computer is a personal computer that provides the full capabilities of a desktop computer while remaining mobile. They are often larger, bulkier laptops...

  • e-waste
  • Information and communication technologies for development
    Information and communication technologies for development
    Information and Communication Technologies for Development is a general term referring to the application of Information and Communication Technologies within the fields of socioeconomic development, international development and human rights...

  • List of computer system manufacturers
  • Market share of leading PC vendors
    Market share of leading PC vendors
    Because the personal computer is an iconic high tech product the market share of leading PC vendors is watched closely. Market discussion of these devices may include netbooks but do not include media tablets which was dominated by Apple products....

  • Personal Computer Museum
    Personal Computer Museum
    The Personal Computer Museum is located in Brantford, Ontario, Canada, located in a former city building that is built from reclaimed bricks from the Brantford Opera House....

  • Public computer
    Public computer
    A public computer is any of various computers available in public areas. Some places where public computers may be available are libraries, schools, or facilities run by government....

  • Quiet PC
    Quiet PC
    A quiet PC is a personal computer that makes little noise. Common uses for quiet PCs include video editing, sound mixing, home servers, and home theater PCs. A typical quiet PC uses quiet cooling and storage devices and energy-efficient parts....

  • Trashware
    Trashware
    Trashware in North America or Totally reconditioned hardware in the UK and Ireland is computer equipment that is assembled from old hardware, using cleaned and checked parts from different computers, for use by disadvantaged people to bridge the digital divide.Trashware, with its social aims, is...

  • Computer case
    Computer case
    A computer case is the enclosure that contains most of the components of a computer...


Further reading

  • Accidental Empires: How the boys of Silicon Valley
    Silicon Valley
    Silicon Valley is a term which refers to the southern part of the San Francisco Bay Area in Northern California in the United States. The region is home to many of the world's largest technology corporations...

     make their millions, battle foreign competition, and still can't get a date
    , Robert X. Cringely, Addison-Wesley Publishing, (1992), ISBN 0-201-57032-7

External links