Personal computer: Difference between revisions

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[[Image:Computer-aj_aj_ashton_01.svg|thumb|right|300px|A stylised [[illustration]] of a modern personal computer]]
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A '''personal computer''' ('''PC''') is a [[computer]] whose [[price]], size, and features make it suitable for personal use.   Personal computers are intended for use by one user, as compared with [[server (computer)|servers]].  A personal computer, for example, will typically include the ability to play [[music]] and display [[computer graphics|graphics]] quickly.  A server, on the other hand, is intended to be accessed by many users at once over a [[network]]; it is unlikely to include sound or fancy display capability, but instead may be configured with additional [[memory (computers)|memory]] or network connections and a faster [[CPU|processor]].


A '''personal computer''' ('''PC''') is usually a [[computer]] whose price, size, and features make it suitable for personal usage, generally in the home. The term was popularized by [[Apple Computer]] with the [[Apple II]] in the late-1970s and early-1980s, and afterwards by [[International Business Machines|IBM]] with the [[IBM PC]].  Generally, personal computers differ from other types of computers only in terms of their components and function. A [[workstation]] or [[server (computing)|server]] differ from personal computers primarily by function and grades of components used.
The term ''personal computer'' entered common use when small, personally affordable computers became available in the late 1970s. The original PCs were made by [[Apple Inc.|Apple Computer]] with their Apple I and II, Tandy Radio Shack with the TRS-80, and [[Commodore International]] with the [[Commodore PET]] and [[Commodore 64]]. Building on the success of these earlier efforts, [[IBM]] in 1983 introduced the [[IBM PC]].  This development prompted aspiring computer manufacturers such as Compaq to legally reverse engineer the IBM BIOS (the only hardware on the original PC that was proprietary), thus spawning an entire industry devoted to manufacturing "clones." Clones (more technically [[IBM_compatible_PC|IBM compatible PC]]s) were capable of running the same [[Disk Operating System]] as the original IBM PC but on hardware components manufactured by other companies besides IBM.


== Uses ==
== Uses ==
Personal computers are normally operated by one user at a time to perform such general purpose tasks as [[word processing]], [[internet]] browsing, [[internet fax]]ing, [[e-mail]]  and other digital messaging, [[multimedia]] playback, [[Computer and video games | video game]] play, [[computer programming]], etc.  This is in contrast to most other [[consumer electronics]], which tend to specialize in only a few functions, but tend to outperform general purpose PCs at those tasks.  As a result, a [[video game console]] (for example) can generally play video games better than an equally-priced computer, but can't do any of a PC's other functions.
Personal computers tend to be operated by one user at a time to perform [[word processing]], [[internet]] browsing, [[fax]]ing, [[email]]  and other digital messaging, [[multimedia]] playback, [[Computer and video games | video game]] play, [[computer programming]], etc.  This is in contrast to most other [[consumer electronics]], which tend to specialize in only a few functions, but tend to outperform general purpose PCs at those tasks.  As a result, a [[video game console]] (for example) can generally play video games better than an equally-priced computer, but can't do any of a PC's other functions.


The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in or capable of [[programming]] for the computer. Therefore, most [[software]] written primarily for personal computers tends to be designed with simplicity of use, or "[[Usability | user-friendliness]]" in mind. However, the [[software industry]] continuously provides a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.
The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in or capable of [[programming]] for the computer. Therefore, most [[software]] written primarily for personal computers tends to be designed with simplicity of use, or "[[Usability | user-friendliness]]" in mind. However, the [[software industry]] continuously provides a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.
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===Stationary computers===
===Stationary computers===
*'''[[Desktop computer]]s''', frequently simply called desktops, are the largest personal computers.  Often they are designed to fit on or under a desk.  They frequently have the most expansion capabilities and tend to be the fastest, due to the looser size and heat constraints compared to other types of personal computers.  They tend not to include integrated [[computer display|monitor]]s, speakers, keyboards, or other devices, using [[expansion port]]s to connect those components.
*'''[[Desktop computer]]s''', frequently simply called desktops, are the largest personal computers.  Often they are designed to fit on or under a desk.  They frequently have the most expansion capabilities and tend to be the fastest, due to the looser size and heat constraints compared to other types of personal computers.  They tend not to include integrated [[computer display|monitor]]s, speakers, keyboards, or other devices, using [[expansion port]]s to connect those components.
*'''[[All-in-One_PC|All-in-One computers]]''' (often abbreviated AIO) are similar to desktop computers, but tend to integrate some external components into one package.  In a desktop, the monitor, computer, and speakers would be separate components connected by cables, while in an AIO, they would be combined into one package, often by building the computer behind the screen.  One of the most well-known AIOs is the [[Apple Computers|Apple]] [[IMac|iMac]].  An AIO tends to be less powerful and less expandable than a traditional desktop, as it suffers from the same engineering constraints as a portable computer (namely size and weight).
*'''[[All-in-One_PC|All-in-One computers]]''' (often abbreviated AIO) are similar to desktop computers, but tend to integrate some external components into one package.  In a desktop, the monitor, tower case, and speakers would be separate components connected by cables, while in an AIO, they would be combined into one package, often by building the computer behind the screen.  One of the most well-known AIOs is the [[Apple Computers|Apple]] [[IMac|iMac]].  An AIO tends to be less powerful and less expandable than a traditional desktop, as it suffers from the same engineering constraints as a portable computer (namely size and weight).


===Portable computers===
===Portable computers===
[[Portable computers]] are designed for portability, and so are lighter than desktops.  They tend to be slightly more expensive than similarly equipped desktops, due to space and heat constraints.  Most portable computers contain [[battery (electricity) | batteries]] so that they can be used for short periods without access to an [[electrical outlet]].
[[Portable computer]]s are designed for portability, and so are lighter than desktops.  They tend to be slightly more expensive than similarly equipped desktops, due to space and heat constraints.  Most portable computers contain [[battery (electricity) | batteries]] so that they can be used for short periods without access to an [[electrical outlet]].


*'''[[Laptop computer]]s''' (also called notebook computers) are small personal computers designed for mobility. Usually all of the peripherals needed to operate the laptop are built in to a single unit.  They are operated with a keyboard and mouse, and are often nearly comparable to similar desktop computers in terms of processing power.
*'''[[Laptop computer]]s''' (also called notebook computers) are small personal computers designed for mobility. Usually all of the peripherals needed to operate the laptop are built in to a single unit.  They are operated with a keyboard and mouse, and are often nearly comparable to similar desktop computers in terms of processing power.
*'''[[Tablet PC|Tablet computer]]s''' are computers that feature a [[touch screen]].  These tend to be slightly smaller than laptops.  They are often operated with a stylus or a pen instead of a keyboard and mouse, although some models do offer both forms of input.  They are generally slightly more expensive than non-tablet laptops.
*'''[[Tablet PC|Tablet computer]]s''' are computers that feature a [[touch screen]].  These tend to be slightly smaller than laptops.  They are often operated with a [[stylus]] or a pen instead of a keyboard and mouse, although some models do offer both forms of input.  They are generally slightly more expensive than non-tablet laptops.
*'''[[Ultra-Mobile PC]]s''' (UMPC) bridge the gap between laptops/tablets and PDAs.  With a maximum screen size of 7-8 diagonal inches (16-20 cm), they are much smaller than even the smallest laptops at 10-11 diagonal inches, and far smaller than the average 14-15 inch laptop.  UMPCs use touch screens, and can run most applications tablets can run.  Though far less powerful than most laptops, they can run versions of most computer applications.
*'''[[Ultra-Mobile PC]]s''' (UMPC) bridge the gap between laptops/tablets and PDAs.  With a maximum screen size of 7-8 diagonal inches (16-20 cm), they are much smaller than even the smallest laptops at 10-11 diagonal inches, and far smaller than the average 14-15 inch laptop.  UMPCs use touch screens, and can run most applications tablets can run.  Though far less powerful than most laptops, they can run versions of most computer applications.
* '''[[Personal digital assistant]]s (PDAs)''' are handheld devices that share many traits with other portable computers.  They are often used for checking email or calendering, but lack the versitility of computers, and are limited in terms of their software choices.  They are often [[smartphones]], and are sometimes considered a [[consumer electronics]] device.
* '''[[Personal digital assistant]]s (PDAs)''' are handheld devices that share many traits with other portable computers.  They are often used for checking email or calendering, but lack the versatility of computers, and are limited in terms of their software choices.  They are often [[smartphones]], and are sometimes considered a [[consumer electronics]] device.


== Configuration ==
== Configuration ==
[[Image:Personal computer, exploded 5.svg|thumb|right|325px|An exploded view of a modern personal computer:
[[Image:Personal computer exploded 5.png|thumb|right|200px|An exploded view of a modern [[personal computer]]:
<ol>
<ol>
<li>[[Computer display | Display]]
<li>[[Computer display|Display]]
<li>[[Motherboard]]
<li>[[Motherboard]]
<li>[[Central processing unit | CPU]] ([[Microprocessor]])
<li>[[Central processing unit|CPU]] ([[Microprocessor]])
<li>[[Primary storage]] ([[Random access memory | RAM]])
<li>[[Primary storage]] ([[Random access memory|RAM]])
<li>[[Expansion card]]s
<li>[[Expansion card]]s
<li>[[Power supply]]
<li>[[Power supply]]
<li>[[Optical disc | Optical disc drive]]
<li>[[Optical disc|Optical disc drive]]
<li>[[Secondary storage]] ([[Hard disk | HD]])
<li>[[Secondary storage]] ([[Hard disk|HD]])
<li>[[Computer keyboard | Keyboard]]
<li>[[Computer keyboard|Keyboard]]
<li>[[Mouse (computing) | Mouse]]
<li>[[Mouse (computing)|Mouse]]
</ol>]]
</ol>]]
Most personal computers are standardized to the point that purchased software is expected to run with little or no customization for the particular computer. Many PCs are also user-upgradable, especially desktop and workstation class computers. Devices such as main memory, mass storage, even the [[motherboard]] and [[central processing unit]] may be easily replaced by an end user. This upgradeability is, however, not indefinite due to rapid changes in the personal computer industry. A PC that was considered top-of-the-line five or six years prior may be impractical to upgrade due to changes in industry standards. Such a computer usually must be totally replaced once it is no longer suitable for its purpose.
Most personal computers are standardized to the point that purchased software is expected to run with little or no customization for the particular computer. Many PCs are also user-upgradable, especially desktop and workstation class computers. Devices such as main memory, mass storage, even the [[motherboard]] and [[central processing unit]] may be easily replaced by an end user. This upgradeability is, however, not indefinite due to rapid changes in the personal computer industry. A PC that was considered top-of-the-line five or six years prior may be impractical to upgrade due to changes in industry standards. Such a computer usually must be totally replaced once it is no longer suitable for its purpose.


The [[computer hardware | hardware]] capabilities of personal computers can sometimes be extended by the addition of [[expansion card]]s connected via an expansion [[Computer bus | bus]]. Some standard peripheral buses often used for adding expansion cards in personal computers as of 2005 are [[Peripheral Component Interconnect | PCI]], [[Accelerated Graphics Port | AGP]] (a high-speed PCI bus dedicated to graphics adapters), and [[PCI Express]]. Most personal computers as of 2005 have multiple physical [[Peripheral Component Interconnect | PCI]] expansion slots and a PCI Express (PCIe) bus and one or more expansion slots.  Some motherboards contain an AGP bus instead of a PCIe bus, but PCIe has mostly replaced AGP.
The [[computer hardware | hardware]] capabilities of personal computers can sometimes be extended by the addition of [[expansion card]]s connected via an expansion [[Computer bus | bus]]. Some standard peripheral buses often used for adding expansion cards in personal computers are [[Peripheral Component Interconnect | PCI]], [[Accelerated Graphics Port | AGP]] (a high-speed PCI bus dedicated to graphics adapters), and [[PCI Express]]. Most desktop personal computers have multiple physical [[Peripheral Component Interconnect | PCI]] expansion slots and a PCI Express (PCIe) bus and one or more expansion slots.  Some motherboards contain an AGP bus instead of a PCIe bus, but PCIe has mostly replaced AGP.


=== Motherboard ===
=== Motherboard ===
{{main | [[PC motherboard]]}}
The [[motherboard]] (or mainboard) is the primary [[circuit board]] for a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry and ICs for CPU operation, main memory, and facilities for initial setup of the computer immediately after being powered on.  Boot [[firmware]] or a [[BIOS]] is often held in a small piece of [[non-volatile]] memory, such as [[Flash memory]].
 
With high-performance processors and sometimes memory, component-specific cooling fans may be above the component on the motherboard, with the heat sink and fan being mechanically locked to the component socket on the motherboard. Installing a large, heavy cooling assembly over a processor easily may be the most physically difficult part of assembling a PC.
 
Additionally, it contains connectors for [[#Mass storage|hard drives]] and [[#Removable storage|optical or floppy drives]].  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. Some higher-end motherboards have a secondary [[daughter board]] attached to provide further expandability or to satisfy space constraints.
 
Especially in modular "tower" computers, the motherboard is as important as a place of interconnection as a place where the processor and memory operate.  The power supplies often cable to the motherboard, from which power is supplied to cards that plug into PCI and the like. Depending on the disk type, it may get all its power from the motherboard, or, when there are multiple disks of the same type, the first may get power from the motherboard, and then the other disks are "daisy-chained" to pass both signals and power.


The motherboard (or mainboard) is the primary [[circuit board]] for a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry and ICs for CPU operation, main memory, and facilities for initial setup of the computer immediately after being powered on.  Boot [[firmware]] or a [[BIOS]] is often held in a small piece of [[non-volatile]] memory, such as [[Flash memory]] . 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. Some higher-end motherboards have a secondary [[daughter board]] attached to provide further expandability or to satisfy space constraints.
In laptops, the motherboard may be sufficiently "all-in-one" that almost any repair may need it to be replaced, which, if the computer is a year or so old, may not be economic. It can be frustrating when the problem is no more than an external power connector at the edge of the motherboard, which lines up with the external jack  on the case into which the external power supply/battery charger, which breaks loose due to power connector stresses. An occasional highly skilled technician sometimes can solder it back in place, but that is not the factory recommended technique.


=== Central processing unit ===
=== Central processing unit ===
{{main | Central processing unit}}
The central processing unit, or CPU, is the part of the computer that executes operations.  Computer software [[Computer program | programs]], including the [[operating system]], consists of millions of processor instructions encoded in [[binary]].  Nearly all PCs contain a type of CPU known as a microprocessor. The microprocessor often plugs into the motherboard using one of many different types of sockets. [[IBM compatible PC]] computers use an [[x86]]-compatible processor.  [[Intel]] makes most of the processors in personal computers, with [[AMD]] being it's closest competitor.  [[Via]] and [[Transmeta]] also make x86 processors.  Other types of computers might use [[Power PC]], [[SPARC]] or other types of CPUs, however nearly all computers sold to home users use x86 processors.


The central processing unit, or CPU, is the part of the computer that executes software [[Computer program | programs]], including the [[operating system]]. Nearly all PCs contain a type of CPU known as a microprocessor. The microprocessor often plugs into the motherboard using one of many different types of sockets. [[IBM PC compatible]] computers use an [[x86]]-compatible processor, usually made by [[Intel]], [[AMD]], [[VIA Technologies]] or [[Transmeta]]. Other computers use [[Power PC]] (a [[RISC]] architecture), [[SPARC]] or other types of CPUs.
Personal computers generally have only a single processor package, which may have two or four cores.  Each core is essentially an independent processor.  Each processor package fits into a [[CPU socket|socket]]. Workstations and servers may have multiple sockets, but nearly all personal computers have only a single socket.


=== Main memory ===
=== Main memory ===
{{main | Primary storage}}
A PC's main memory place (or primary storage) is fast storage space that is directly accessible by the CPU, used to store the currently executing program and immediate data. PCs use semiconductor [[random access memory]] such as [[SDRAM]] as their primary storage.  Main memory is usually much faster than mass storage devices like [[hard disk]]s or [[optical disc]]s, but cannot retain data without power and is more expensive than mass storage. Therefore, it is not generally suitable for long-term or archival data storage.
 
[[Image:4mbramvax.jpg|thumb|right|200px|A four-[[megabyte]] RAM card measuring about twenty-two by fifteen inches (55.8 by 38.1 centimeters); made for the [[VAX]] 8600 [[minicomputer]] (circa 1986). [[Dual in-line package | Dual in-line package (DIP)]]&nbsp; [[Integrated circuit]]s populate nearly the whole board; the RAM chips are in the majority located in the rectangular areas to the left and right.]]
 
A PC's main memory place (or primary storage) is fast storage space that is directly accessible by the CPU, used to store the currently executing program and immediate data. PCs use semiconductor [[random access memory]] such as [[DRAM]] or [[SRAM]] as their primary storage.  Main memory is usually much faster than mass storage devices like [[hard disk]]s or [[optical disc]]s, but cannot retain data without power and is more expensive than mass storage. Therefore, it is not generally suitable for long-term or archival data storage.


=== Mass storage ===
=== Mass storage ===
{{main | Hard disk}}
Mass storage stores programs and data without consuming power. Although semiconductor [[flash memory]] has dropped in cost, the prevailing form of mass storage in personal computers is still the electromechanical [[hard disk]].


[[Image:Hard disk dismantled.jpg|thumb|right|Internals of a Winchester disk]]
A computer's hard disk stores most of the user's data, including their [[operating system]], [[computer program|applications]], media, and documents. On a [[Microsoft Windows]] computer, this is represented by the "C:" drive.


Mass storage stores programs and data without consuming power. Although semiconductor [[flash memory]] has dropped in cost, the prevailing form of mass storage in personal computers is still the electromechanical [[hard disk]].
If the mass storage controller (often on the [[#Motherboard|motherboard]]) provides for expandability, a PC may also be upgraded by the addition of extra hard disks or removable storage drives.  Standard internal storage device interfaces are [[Advanced Technology Attachment | ATA]] and [[Serial ATA]], with SATA being the faster of the two.  Other types of internal storage device interfaces include [[SCSI]] and CF+ Type II. A hard drive usually takes up a 3.5 inch or 2.5 inch bay inside a computer.
<!-- Generalize and clean up this article section. -->


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.
===Removable storage===
 
Removable storage drives include [[DVD]], [[CD]], and [[floppy disk]] drives, as well as flash card readers. In most cases, removable storage drives are bigger than hard drives, requiring a 5.25 inch bay.  Drives are generally named by what sort of actions they can perform on a type of media.  For instance, a  "DVD-ROM" drive can read DVDs, because "ROM" stands for "Read-Only Memory".  A "CD-R" drive can record once to a CD, and also read CDs, because the "-R" stands for "recordable".  A "CD-RW" drive can read and rewrite CDs, because "-RW" stands for "re-writeable".
If the mass storage controller provides for expandability, a PC may also be upgraded by the addition of extra hard disk or optical drives. For example, [[DVD | DVD-ROM]]s, [[CD-ROM]]s, and various [[optical disc recorder]]s may all be added by the user to certain PCs. Standard internal storage device interfaces are [[Advanced Technology Attachment | ATA]], [[Serial ATA]], [[SCSI]], and CF+ Type II in 2005.


=== Graphics - Video card ===
=== Graphics - Video card ===
{{main | Graphics card}}
The [[graphics processing unit]] (GPU) is responsible for handling the graphics output of the computer, usually to a [[computer monitor|monitor]].  A GPU contains a special-purpose processor and its own memory.  GPUs usually handle one or two outputs, often in forms like [[Video Graphics Adapter|VGA]], [[DVI]], and [[S-Video]]. In some computers, GPUs can also handle other functions, such as [[digital video|video]] decoding.
<!-- This section probably needs to be moved out of architecture and covered in dialogue about peripheral devices. Nothing mandates that a personal computer contains a display adapter, and they're plenty of counterexamples. -->
 
The graphics card - otherwise called a graphics adapter, video adapter, or video card processes and renders the graphics output from the computer to the [[VDU]] or computer [[Computer display | monitor]] and is an essential part of the modern computer. On older and budget models graphics cards tended to be integrated with the motherboard but, more commonly, they are supplied in [[Peripheral Component Interconnect | PCI]], [[Accelerated Graphics Port | AGP]], or [[PCI Express]] format.
 
At the introduction of the IBM PC, many personal computers used text-only display adapters and had no graphics capability.
 
== History ==
{{main | History of computing hardware (1960s-present)}}
 
[[Image:Televideo925Terminal.jpg|thumb|right|250px|[[Time share]] "[[Computer terminal | terminals]]" to central computers were sometimes used before the advent of the PC, such as the smart terminal — televideo [[ASCII]] character mode terminal pictured here.]]
 
=== Mainframes and large 'minicomputers' ===
 
Before the advent of the [[microprocessor]] in the mid 1970s, computers were generally large costly systems owned by universities, institutions and  large companies. To make efficient use of computer time, end users often did not directly interact with the machine but instead would prepare tasks for the computer on off-line equipment such as card punches.  A number of assignments for the computer would be gathered up and processed in [[batch processing | batch mode]].  After the job had completed, users could collect the results. In some cases it could take hours or days between submitting a job to the computing center and receiving the output.
 
A more interactive form of computer use developed commercially by the middle 1960's. In a [[time-sharing]] system, multiple [[computer terminal]]s let many people share the use of one [[mainframe computer]] processor. This was common in business applications, and in sciences and engineering.
<!-- The minicomputer commentary should probably be cut down a bit more. Their development and usage isn't really all that relevant to this article. Disagree, it's absolutely relelevant! -->
 
A different model of computer use was foreshadowed by the way in which early, pre-commercial, experimental computers were used, where one user had exclusive use of a processor. Some of the first computers that might be called "personal" were early [[minicomputer]]s such as the [[LINC]] and [[PDP-8]], and later on [[VAX]] and larger minicomputers from [[Data General]], [[Prime computer | Prime]], and others.  By today's standards they were very large (about the size of a refrigerator) and cost prohibitive (typically tens of thousands of [[United States dollar | US dollars]]), and thus were rarely purchased by an individual. However, they were much smaller, less expensive, and generally simpler to operate than many of the mainframe computers of the time. Therefore, they were accessible for individual laboratories and research projects. Minicomputers largely freed these organizations from the [[batch processing]] and bureaucracy of a commercial or university computing center.
 
In addition, minicomputers were relatively interactive and soon had their own [[operating system]]s. The minicomputer [[Xerox Alto]] ([[1973]]) was a landmark step in the development of personal computers, because of its [[graphical user interface]], [[bit-map]]ped high resolution screen, large internal and external memory storage, [[Mouse (computing) | mouse]], and special software. <ref>Rheingold, H. (2000). Tools for thought: the history and future of mind-expanding technology (New ed.). Cambridge, MA etc.: The MIT Press.</ref> The minicomputer era was an intermediary step from mainframes to personal computer usage.
 
=== Computers at home ===
 
One early use of the term "personal computer" appeared in a [[November 3]], [[1962]] ''[[The New York Times | New York Times]]'' article reporting [[John W. Mauchly]]'s vision of future computing as detailed at a recent meeting of the American Institute of Industrial Engineers. Mauchly stated, "There is no reason to suppose the average boy or girl cannot be master of a personal computer.<ref>{{cite news | title=Pocket Computer May Replace Shopping List | publisher=New York Times | date=[[1962-11-03]]}}</ref>"
 
The ancestors of the modern personal computer did not use microprocessors, which explained their size and high cost. After the commercialization of the "computer-on-a-chip", the cost of manufacture of a computer system dropped dramatically. The arithmetic, logic, and control functions that previously occupied several costly circuit boards were now available in integrated form.  Concurrently, advances in the development of solid-state memory eliminated the bulky, costly, and power-consuming core storage used in prior generations of computers.
 
A programmable terminal called the [[Datapoint 2200]] is the earliest known device that bears any significant resemblance to the modern personal computer<ref>http://www.americanheritage.com/articles/magazine/it/1994/2/1994_2_64.shtml</ref><ref>http://www.old-computers.com/museum/computer.asp?st=1&c=596</ref>.  It was made by [[Datapoint | CTC]] (now known as Datapoint) in [[1970]] and was a complete system in a small case bearing the approximate footprint of an [[IBM]] [[Selectric]] [[typewriter]].  The system's CPU was constructed from a variety of discrete components, although the company had commissioned [[Intel]] to develop a single-chip processing unit; there was a falling out between CTC and Intel, and the chip Intel had developed wasn't used.  Intel soon released a modified version of that chip as the [[Intel 8008]], the world's first 8-bit microprocessor<ref>A History of Modern Computing, (MIT Press), pp. 220–21</ref>.  The needs and requirements of the Datapoint 2200 therefore determined the nature of the 8008, upon which all successive processors used in IBM-compatible [[IBM PC | PC]]s were based.  Additionally, the design of the Datapoint 2200's multi-chip CPU and the final design of the Intel 8008 were so similar that the two are largely software-compatible; therefore, the Datapoint 2200, from a practical perspective, can be regarded as if it were indeed powered by an 8008, which makes it a strong candidate for the title of "first [[microcomputer]]" as well.
 
Development of the single-chip [[microprocessor]] was an enormous catalyst to the popularization of cheap, easy to use, and truly personal computers.  The [[Altair 8800]], introduced in a [[Popular Electronics]] magazine article in 1975, at the time set a new low price point for a computer, bringing computer ownership to an admittedly select market in the 1970s. It was arguably this computer that spawned the development of both [[Apple Computer]] as well as [[Microsoft]], spawning the [[Altair BASIC]] programming language interpreter, Microsoft's first product. The second generation of [[microcomputer]]s — those that appeared in the late 1970s, sparked by the success of the [[Steve Wozniak]]-designed Apple release, the [[Apple II]] — were usually known as [[home computer]]s. These were less capable and in some ways less versatile than large business computers of the day. They were generally used by computer enthusiasts for learning to [[computer programming | program]], running simple office/productivity applications, electronics interfacing, and general hobbyist pursuits. By the late 1990's, the  "home computer" was becoming a less common label in favor of "personal computer." The graphics and sound capacities of "home" systems were matched by those intended for "business" purposes, with a general decrease in costs.  The two market segments fused. These computers were pre-assembled, often pre-configured with bundled software,  and required little technical knowledge to operate.
 
[[Image:Computer lab showing desktop PCs warwick.jpg|thumb|left|250px|A university computer lab containing many desktop PCs]]
 
[[Image:IBM PC 5150 Image.jpg|thumb|right|250px|A release photo of the original IBM PC (ca. 1981)]]
 
=== Back to business ===
<!-- Feh... this is a bit of a strong claim. Need to rethink it. -->
 
It was the launch of the [[VisiCalc]] [[spreadsheet]], initially for the [[Apple II family | Apple II]] (and later for the [[Atari 8-bit family]], [[Commodore PET]], and [[IBM PC]]) that turned the microcomputer into a business tool. This was followed by the [[August 12]] [[1981]] release of the [[IBM PC]] which would revolutionize the computer market. The [[Lotus 1-2-3]], a combined spreadsheet (inspired by VisiCalc), presentation graphics, and simple database application, would become the PC's own killer app. Good [[word processor]] programs would also appear for many home computers, in particular the introduction of [[Microsoft Office Word | Microsoft Word]] for the [[Apple Macintosh]] in 1985 (While earlier versions of Word had been created for the PC, it became popular initially through the Macintosh.).
 
In the [[January 3]] [[1983]] issue of ''[[Time (magazine) | Time]]'' magazine, the personal computer was named the "Person of the Year" for 1982.
 
=== Today ===
<!-- This needs to talk more about the fact that microcomputers simply became the dominant form of computer, and standardization led to similar components being used for high-end computers and PCs. -->
 
During the 1990s, the power of personal computers increased radically, blurring the formerly sharp distinction between personal computers and multi-user computers, such as [[mainframe]]s. Today higher-end computers often distinguish themselves from personal computers by greater reliability or greater ability to multitask, rather than by brute [[central processing unit | CPU]] ability.
 
In today's common usage, personal computer and PC usually indicate an [[IBM PC compatible]]. Due to this association, some manufacturers of personal computers that are not IBM PCs avoid explicitly using the terms to describe their products. Mostly, the term PC is used to describe personal computers that use [[Microsoft Windows]] [[operating system]]s.
<!-- Due to networks and the Internet, modern personal computers are n o longer the exclusive tools of their users.  Support of desktop computers in business now requires as much bureaucracy and professional training as did operating a time-sharing system, with the draw back of much lower security and users skilled enough to get into deep trouble but not skilled enough to get out.  We should talk about the collapse of the "people's computer" paradigm and the re-corporatization of the computer. -->
 
== Non IBM-compatible personal computers ==
 
Though many personal computers are [[IBM PC compatible|compatible with IBM PCs]] using either Microsoft Windows or [[Unix-like]]s such as [[Linux]], a number of other personal computer types are also popular.  Note that in many regions, in popular usage the term "PC" (though simply short for "personal computer") has become synonymous with "IBM PC–compatible."
 
A leading alternative to the IBM-compatible PC is the [[Macintosh]] (thus the commonly heard comparative, "PC vs. Mac"). The Macintosh originally used the [[Motorola 68000]] series, then shifted to the IBM and Motorola [[PowerPC]] processors. This makes the term “IBM-compatible” particularly ironic, since the Macintosh was powered by an IBM chip, though neither IBM PCs nor so-called “IBM-compatibles” were.
 
In January, 2006, Apple shifted its architecture to the same Intel processor family found in many so-called “IBM-compatibles.”
 
===List of other non IBM compatible PC's===
 
'''Pre-PC systems'''
This is a list of non IBM PC compatible business personal computers (PC), and Personal Workstation (PW) computers, that came on the market '''before''' the IBM-PC.


* [[Apple III]] designed as a business system by [[Apple Inc.]]
A graphics unit can be dedicated or integrated. A dedicated graphics unit is normally housed on an expansion card and connected to the motherboard by an expansion slot, such as [[PCI Express|PCIe]] or [[Accelerated Graphics Port|AGP]], and includes dedicated RAM for the graphics coprocessor to use.  An integrated graphics solution borrows RAM from the processor to do its work.  Generally, lower-end PCs or smaller PCs tend to have integrated graphics solutions, while midrange or high-end PCs have dedicated graphics cards.  [[Gaming PC]]s sometimes include more than one graphics card.
* [[Astrocom 760]] by [[Astrocom Corporation]]
* [[Commodore PET|CBM series]] machines by [[Commodore International]]
* [[CompuColor 8001]] by [[Intecolor]]
* [[DEC Professional (computer)]] from [[Digital Equipment Corporation]]
* [[DPS-1]] by [[Intersystems]]
* [[NorthStar Horizon]] by [[North Star Computers]]
* [[HP-85A]] From [[Hewlett-Packard]]
* [[MSI computer]] systems from [[Midwest Scientific Instruments]]
* [[M20]] from [[Olivetti]]
* [[Noval 760]] by [[Noval/Gremlin]]
* [[PC-9800]] system from [[NEC]]
* [[RCC REX]] by [[Realistic Controls Corporation]]
* [[S-100 bus]] systems, build from components made by various companies
* [[C4P]] and C8P systems made by [[Ohio Scientific]]
* [[SBC/9]] by [[Percom]]
* [[SBS-8000]] by [[Small Business systems]]
* [[Sol-20]] by [[Processor Technology]]
* [[Sphere computer]] by [[Sphere inc.]]
* [[Superbrain]] by [[intertec Data Systems]]
* [[SWTPC]] systems
* [[TRS-80|TRS-80 model II]] by [[Tandy Corporation]]
* [[Victor 9000]] by [[Sirius Systems Technology]]
* [[Z-89]] by [[Zenith Electronics|Zenith]]/[[Heathkit]]


'''Post-PC systems'''
=== Sound Card ===
This is a list of non IBM PC compatible business personal computers (PC), and Personal Workstation (PW) computers, that came on the market '''after''' the IBM-PC.
The sound card is responsible for the input and output of computer audio.  A PC sound card generally has at least two (Line-In/Line-Out) stereo ports. Like the GPU and ethernet card, the sound card can be both dedicated or integrated.
 
* [[Acorn Archimedes]] & [[RiscPC]]
* [[ACT Apricot]] by [[ACT]] (Runs MS-DOS but is NOT IBM PC compatible.) <ref name="nopc">This means that MS-DOS is ported to this machine, and is using BIOS calls to interface with the hardware, but the architecture of the hardware is completely different. So IBM-PC software that directly writes to (for example) the video screen (which almost all software did) won't work.  The differences with the IBM-PC architecture could be huge. Especially the memory mapping and the video display hardware, but even simple things like the way the keyboard was interfaced to the system could be completely different</ref>
* [[Apple Lisa]] by [[Apple Inc.]]
* [[Amiga]] (previously produced by [[Commodore International | Commodore]], now under license from Amiga Inc.)
* [[Amstrad PCW]] series (Personal Computer Word processor) from [[Amstrad]]
* [[Atari]] [[Atari ST | ST]]
* [[BeOS]] [[BeBox]]
* [[C-10]] by Cromemco
* [[Compustar II VPU Model 20]] by [[Intertec]]
* [[Corvus Concept]] by [[Corvus Systems]]
* [[HP 150]] by [[Hewlett-Packard]]. (Runs MS-DOS but is NOT IBM PC compatible.) <ref name="nopc"/>
* [[Kaypro 10]] by [[Kaypro]]
* [[Knowledge Worker]] by [[A.B.Dick Comp.]]
* [[Micro 16s]] by [[Fujitsu]]
* [[Micro Decision]] by [[Morrow Designs]]
* [[NeXT]] workstations by [[Next|Next Software]]
* [[PC-8800]] by [[NEC]]
* [[Pegasos]] by [[Genesi]]
* [[QX-10]] by [[Epson]]
* [[Rainbow 100]] from [[Digital Equipment Corporation]] (Runs MS-DOS but is NOT IBM PC compatible.) <ref name="nopc"/>
* [[RoadRunner]] from [[MicroOffice]]
* [[Silicon Graphics | SGI]] workstations like the [[SGI Indigo]] and [[SGI Onyx]]
* [[Sun Microsystems | Sun]] [[SPARCstation]]
* [[TI Professional]] Computer by [[Texas Instruments]]
* [[Tulip System-1]] by [[Tulip Computers]] company. (Runs MS-DOS but is NOT IBM PC compatible.) <ref name="nopc"/>
 
The term "personal computer" is often avoided by advocates of the above computer systems, because of the association with the "PC" in "IBM PC".
 
IBM-compatible is a historical term since [[IBM]] no longer manufactures personal computers. It is still a short-hand way of designating, especially during the period 1981–1997, a computer generally similar to the original IBM PC, XT and AT.  Pragmatically, the operational definition of "compatible personal computer" is now "capable of running the current edition of Microsoft Windows".


=== Power Supply ===
The power supply is needed to deliver the electricity to each of the components of the PC, either individually or through the motherboard.  It converts AC power to a few different voltages of DC power.  Each different voltage line is sometimes referred to as a "rail".  The consumption of the components and the output of the power supply is limited by the current on each rail.  In order for the PC to perform at its peak, the output of the power supply on each rail must be greater than or equal to the sum of the maximum consumptions of the components using that rail.  Usually, the limiting rail is the +12V rail because this feeds the CPU, the GPU, and the drives.


== See also ==
== See also ==
* [[Apple Computer]], [[Apple II family | Apple II]], [[Apple Lisa]], and [[Apple Macintosh]]
* [[Computer]]
* [[Desktop replacement computer]]
* [[Gaming PC]]
* [[Gaming PC]]
* [[History of computing hardware (1960s-present)]]
* [[Home computer]]
* [[Laptop]]
* [[Silent PC]]
* [[Silent PC]]
* [[HTPC]]
* [[HTPC]]
* [[Microcomputer]]
* [[Minicomputer]]
* [[Mainframe computer]]
* [[Osborne 1]]
* [[Supercomputer]]
* [[Xerox Star]]
==Notes==
<!-- ----------------------------------------------------------
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  discussion of different citation methods and how to generate
  footnotes using the <ref>, </ref> and  <reference /> tags
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<div class="references-small">
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== External links ==
* [http://www.old-computers.com/ Old Computers Museum] (all computer types)
* [http://pc-museum.com/ Rune's PC Museum]
* [http://www.custompcguide.com/ Custom PC Guide] A regularly updated PC/HTPC buyer's guide.
* [http://www.pcguide.com/ The PC Guide] contains detailed historical and technical information.
* [http://computer.howstuffworks.com/pc.htm Howstuffworks' article on "How PCs Work"]
* [http://pc.wikicities.com Wikicity for PC enthuiasm]
* [http://www.blinkenlights.com/pc.shtml BlinkenLights Archaeological Insititute - Personal Computer Milestones] What was the first personal computer?
* [http://arstechnica.com/articles/culture/total-share.ars/ "Total share: 30 years of personal computer market share figures"] — From [[Ars Technica]]


[[Category:Personal computers | *Personal]]
{{reflist}}
[[Category:Office equipment]]
[[Category:Time magazine Persons of the Year]]
[[Category:Computers Workgroup (Top)]]
[[Category:CZ LIve]]

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A personal computer (PC) is a computer whose price, size, and features make it suitable for personal use. Personal computers are intended for use by one user, as compared with servers. A personal computer, for example, will typically include the ability to play music and display graphics quickly. A server, on the other hand, is intended to be accessed by many users at once over a network; it is unlikely to include sound or fancy display capability, but instead may be configured with additional memory or network connections and a faster processor.

The term personal computer entered common use when small, personally affordable computers became available in the late 1970s. The original PCs were made by Apple Computer with their Apple I and II, Tandy Radio Shack with the TRS-80, and Commodore International with the Commodore PET and Commodore 64. Building on the success of these earlier efforts, IBM in 1983 introduced the IBM PC. This development prompted aspiring computer manufacturers such as Compaq to legally reverse engineer the IBM BIOS (the only hardware on the original PC that was proprietary), thus spawning an entire industry devoted to manufacturing "clones." Clones (more technically IBM compatible PCs) were capable of running the same Disk Operating System as the original IBM PC but on hardware components manufactured by other companies besides IBM.

Uses

Personal computers tend to be operated by one user at a time to perform word processing, internet browsing, faxing, email and other digital messaging, multimedia playback, video game play, computer programming, etc. This is in contrast to most other consumer electronics, which tend to specialize in only a few functions, but tend to outperform general purpose PCs at those tasks. As a result, a video game console (for example) can generally play video games better than an equally-priced computer, but can't do any of a PC's other functions.

The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in or capable of programming for the computer. Therefore, most software written primarily for personal computers tends to be designed with simplicity of use, or " user-friendliness" in mind. However, the software industry continuously provides a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.

Types of Personal computers

Personal computers are generally divided into categories based on their size, portability, and capabilities.

Stationary computers

  • Desktop computers, frequently simply called desktops, are the largest personal computers. Often they are designed to fit on or under a desk. They frequently have the most expansion capabilities and tend to be the fastest, due to the looser size and heat constraints compared to other types of personal computers. They tend not to include integrated monitors, speakers, keyboards, or other devices, using expansion ports to connect those components.
  • All-in-One computers (often abbreviated AIO) are similar to desktop computers, but tend to integrate some external components into one package. In a desktop, the monitor, tower case, and speakers would be separate components connected by cables, while in an AIO, they would be combined into one package, often by building the computer behind the screen. One of the most well-known AIOs is the Apple iMac. An AIO tends to be less powerful and less expandable than a traditional desktop, as it suffers from the same engineering constraints as a portable computer (namely size and weight).

Portable computers

Portable computers are designed for portability, and so are lighter than desktops. They tend to be slightly more expensive than similarly equipped desktops, due to space and heat constraints. Most portable computers contain batteries so that they can be used for short periods without access to an electrical outlet.

  • Laptop computers (also called notebook computers) are small personal computers designed for mobility. Usually all of the peripherals needed to operate the laptop are built in to a single unit. They are operated with a keyboard and mouse, and are often nearly comparable to similar desktop computers in terms of processing power.
  • Tablet computers are computers that feature a touch screen. These tend to be slightly smaller than laptops. They are often operated with a stylus or a pen instead of a keyboard and mouse, although some models do offer both forms of input. They are generally slightly more expensive than non-tablet laptops.
  • Ultra-Mobile PCs (UMPC) bridge the gap between laptops/tablets and PDAs. With a maximum screen size of 7-8 diagonal inches (16-20 cm), they are much smaller than even the smallest laptops at 10-11 diagonal inches, and far smaller than the average 14-15 inch laptop. UMPCs use touch screens, and can run most applications tablets can run. Though far less powerful than most laptops, they can run versions of most computer applications.
  • Personal digital assistants (PDAs) are handheld devices that share many traits with other portable computers. They are often used for checking email or calendering, but lack the versatility of computers, and are limited in terms of their software choices. They are often smartphones, and are sometimes considered a consumer electronics device.

Configuration

An exploded view of a modern personal computer:
  1. Display
  2. Motherboard
  3. CPU (Microprocessor)
  4. Primary storage (RAM)
  5. Expansion cards
  6. Power supply
  7. Optical disc drive
  8. Secondary storage (HD)
  9. Keyboard
  10. Mouse

Most personal computers are standardized to the point that purchased software is expected to run with little or no customization for the particular computer. Many PCs are also user-upgradable, especially desktop and workstation class computers. Devices such as main memory, mass storage, even the motherboard and central processing unit may be easily replaced by an end user. This upgradeability is, however, not indefinite due to rapid changes in the personal computer industry. A PC that was considered top-of-the-line five or six years prior may be impractical to upgrade due to changes in industry standards. Such a computer usually must be totally replaced once it is no longer suitable for its purpose.

The hardware capabilities of personal computers can sometimes be extended by the addition of expansion cards connected via an expansion bus. Some standard peripheral buses often used for adding expansion cards in personal computers are PCI, AGP (a high-speed PCI bus dedicated to graphics adapters), and PCI Express. Most desktop personal computers have multiple physical PCI expansion slots and a PCI Express (PCIe) bus and one or more expansion slots. Some motherboards contain an AGP bus instead of a PCIe bus, but PCIe has mostly replaced AGP.

Motherboard

The motherboard (or mainboard) is the primary circuit board for a personal computer. Many other components connect directly or indirectly to the motherboard. Motherboards usually contain one or more CPUs, supporting circuitry and ICs for CPU operation, main memory, and facilities for initial setup of the computer immediately after being powered on. Boot firmware or a BIOS is often held in a small piece of non-volatile memory, such as Flash memory.

With high-performance processors and sometimes memory, component-specific cooling fans may be above the component on the motherboard, with the heat sink and fan being mechanically locked to the component socket on the motherboard. Installing a large, heavy cooling assembly over a processor easily may be the most physically difficult part of assembling a PC.

Additionally, it contains connectors for hard drives and optical or floppy drives. 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. Some higher-end motherboards have a secondary daughter board attached to provide further expandability or to satisfy space constraints.

Especially in modular "tower" computers, the motherboard is as important as a place of interconnection as a place where the processor and memory operate. The power supplies often cable to the motherboard, from which power is supplied to cards that plug into PCI and the like. Depending on the disk type, it may get all its power from the motherboard, or, when there are multiple disks of the same type, the first may get power from the motherboard, and then the other disks are "daisy-chained" to pass both signals and power.

In laptops, the motherboard may be sufficiently "all-in-one" that almost any repair may need it to be replaced, which, if the computer is a year or so old, may not be economic. It can be frustrating when the problem is no more than an external power connector at the edge of the motherboard, which lines up with the external jack on the case into which the external power supply/battery charger, which breaks loose due to power connector stresses. An occasional highly skilled technician sometimes can solder it back in place, but that is not the factory recommended technique.

Central processing unit

The central processing unit, or CPU, is the part of the computer that executes operations. Computer software programs, including the operating system, consists of millions of processor instructions encoded in binary. Nearly all PCs contain a type of CPU known as a microprocessor. The microprocessor often plugs into the motherboard using one of many different types of sockets. IBM compatible PC computers use an x86-compatible processor. Intel makes most of the processors in personal computers, with AMD being it's closest competitor. Via and Transmeta also make x86 processors. Other types of computers might use Power PC, SPARC or other types of CPUs, however nearly all computers sold to home users use x86 processors.

Personal computers generally have only a single processor package, which may have two or four cores. Each core is essentially an independent processor. Each processor package fits into a socket. Workstations and servers may have multiple sockets, but nearly all personal computers have only a single socket.

Main memory

A PC's main memory place (or primary storage) is fast storage space that is directly accessible by the CPU, used to store the currently executing program and immediate data. PCs use semiconductor random access memory such as SDRAM as their primary storage. Main memory is usually much faster than mass storage devices like hard disks or optical discs, but cannot retain data without power and is more expensive than mass storage. Therefore, it is not generally suitable for long-term or archival data storage.

Mass storage

Mass storage stores programs and data without consuming power. Although semiconductor flash memory has dropped in cost, the prevailing form of mass storage in personal computers is still the electromechanical hard disk.

A computer's hard disk stores most of the user's data, including their operating system, applications, media, and documents. On a Microsoft Windows computer, this is represented by the "C:" drive.

If the mass storage controller (often on the motherboard) provides for expandability, a PC may also be upgraded by the addition of extra hard disks or removable storage drives. Standard internal storage device interfaces are ATA and Serial ATA, with SATA being the faster of the two. Other types of internal storage device interfaces include SCSI and CF+ Type II. A hard drive usually takes up a 3.5 inch or 2.5 inch bay inside a computer.

Removable storage

Removable storage drives include DVD, CD, and floppy disk drives, as well as flash card readers. In most cases, removable storage drives are bigger than hard drives, requiring a 5.25 inch bay. Drives are generally named by what sort of actions they can perform on a type of media. For instance, a "DVD-ROM" drive can read DVDs, because "ROM" stands for "Read-Only Memory". A "CD-R" drive can record once to a CD, and also read CDs, because the "-R" stands for "recordable". A "CD-RW" drive can read and rewrite CDs, because "-RW" stands for "re-writeable".

Graphics - Video card

The graphics processing unit (GPU) is responsible for handling the graphics output of the computer, usually to a monitor. A GPU contains a special-purpose processor and its own memory. GPUs usually handle one or two outputs, often in forms like VGA, DVI, and S-Video. In some computers, GPUs can also handle other functions, such as video decoding.

A graphics unit can be dedicated or integrated. A dedicated graphics unit is normally housed on an expansion card and connected to the motherboard by an expansion slot, such as PCIe or AGP, and includes dedicated RAM for the graphics coprocessor to use. An integrated graphics solution borrows RAM from the processor to do its work. Generally, lower-end PCs or smaller PCs tend to have integrated graphics solutions, while midrange or high-end PCs have dedicated graphics cards. Gaming PCs sometimes include more than one graphics card.

Sound Card

The sound card is responsible for the input and output of computer audio. A PC sound card generally has at least two (Line-In/Line-Out) stereo ports. Like the GPU and ethernet card, the sound card can be both dedicated or integrated.

Power Supply

The power supply is needed to deliver the electricity to each of the components of the PC, either individually or through the motherboard. It converts AC power to a few different voltages of DC power. Each different voltage line is sometimes referred to as a "rail". The consumption of the components and the output of the power supply is limited by the current on each rail. In order for the PC to perform at its peak, the output of the power supply on each rail must be greater than or equal to the sum of the maximum consumptions of the components using that rail. Usually, the limiting rail is the +12V rail because this feeds the CPU, the GPU, and the drives.

See also

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