A
personal computer (
PC) is any general-purpose
computerA computer is a machine that manipulates data according to a set of instructions.Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century . These were the size of a large room, consuming as...
whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator. This is in contrast to the batch processing or time-sharing models which allowed large expensive
mainframeMainframes are computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term probably had originated from the early mainframes, as...
systems to be used by many people, usually at the same time, or large data processing systems which required a full-time staff to operate efficiently.
A personal computer may be a
desktop computerA 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. Prior to the wide spread of microprocessors, a computer that could fit on a desk was considered remarkably small...
, a
laptopA laptop is a personal computer designed for mobile use and small and light enough to sit on one's lap while in use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device , speakers, and often including a battery, into a single...
,
tablet PCIn general terms, tablet PC refers to a laptop or slate-shaped mobile computer, equipped with a touchscreen or graphics tablet/screen hybrid to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse....
or a
handheld PCA 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...
(also called
palmtop). The most common microprocessors are x86-compatible CPUs,
ARM architectureThe ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Limited. It was known as the Advanced RISC Machine, and before that as the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in terms of numbers produced...
CPUs and
PowerPCPowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM. Originally intended for personal computers, PowerPC CPUs have since become popular embedded and high-performance processors...
CPUs. Software applications for personal computers include
word processingWord 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 browserA 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-mailElectronic mail, often abbreviated as email or e-mail, is a method of exchanging digital messages, designed primarily for human use...
clients,
gamesA personal computer game is a game played on a personal computer, rather than on a video game console or arcade machine...
, and myriad personal productivity and special-purpose software. Modern personal computers often have high-speed or dial-up connections to the Internet, allowing access to the
World Wide WebThe World Wide Web is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks...
and a wide range of other resources.
A PC may be used at home, or may be found in an office. Personal computers can be connected to a
local area networkA local area network is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport...
(LAN) either by a cable or wirelessly.
While early PC owners usually had to write their own programs to do anything useful with the machines, today's users have access to a wide range of commercial and non-commercial software which is provided in ready-to-run form. Since the 1980s,
MicrosoftMicrosoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices...
and Intel have been dominating much of the personal computer market with the
WintelWintel is portmanteau of Windows and Intel. It usually means a computer based on an Intel x86 compatible processor and running the Microsoft Windows operating system.-Background:...
platform.
History
The capabilities of the personal computer have changed greatly since the introduction of electronic computers.
By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a
computer systemThe 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. The introduction of the
microprocessorA microprocessor incorporates most or all of the functions of a central processing unit on a single integrated circuit . The first microprocessors emerged in the early 1970s and were used for electronic calculators, using binary-coded decimal arithmetic on 4-bit words...
, a single
chipIn electronics, an integrated circuit is a miniaturized electronic circuit that has been manufactured in 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 about 1975. In what was later to be called
The Mother of All DemosThe Mother of All Demos is a name given retrospectively to Douglas Engelbart's December 9, 1968 demonstration at the Fall Joint Computer Conference at the Convention Center in San Francisco, in which a number of experimental technologies that have since become commonplace were presented...
,
SRISri may refer to:*Sri, a Hindu honorific; not to be confused with Sir, a title of respect used in several modern contexts*Sri Lanka, an island state at the south tip of India, formerly called Ceylon*SRi, a car specification badge...
researcher Douglas Englebart 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.
Early personal computers - generally called microcomputers - were sold often in
Electronic kitThe MITS Altair 8800 was a microcomputer design from 1975, based on the Intel 8080 CPU and sold as a mail-order kit through advertisements in Popular Electronics, Radio-Electronics and other hobbyist magazines. The designers intended to sell only a few hundred to hobbyists, and were surprised when...
form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done by toggle switches, and output was provided by front panel indicators. Practical use required peripherals such as keyboards,
computer terminalA computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...
s, disk drives, and printers.
MicralAccording to the Computer History Museum, the Micral N was the earliest commercial, non-kit personal computer based on a microprocessor, the Intel 8008....
N was the earliest commercial, non-kit "personal" computer based on a microprocessor, the Intel 8008. It was built starting in 1972 and about 90,000 units were sold. Unlike other hobbyist computers of its day, which were sold as electronics kits, in 1976 Steve Jobs and Steve Wozniak sold the Apple I computer circuit board, which was fully prepared and contained about 30 chips. The first complete personal computer was the
Commodore PETThe PET was a home/personal computer produced by Commodore starting in 1977. It was a top seller in the Canadian, US, and UK educational markets, and was Commodore's first full-featured computer and would form the basis for their entire 8-bit platform.-Origins and the early models:In the 1970s,...
introduced in January 1977. It was soon followed by the popular
Apple IIThe Apple II was one of the first highly successful mass produced microcomputer products, manufactured by Apple Computer and introduced in 1977...
. Mass-market pre-assembled computers allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware.
Throughout the late 1970s and into the 1980s,
computerHome computer was a class of personal computer entering the market in 1977 and becoming increasingly common during the 1980s. They were marketed to consumers as accessible personal computers, more capable than video game consoles...
s were developed for household use, offering personal productivity, programming and games. Somewhat larger and more expensive systems (although still low-cost compared with
minicomputerA 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
mainframeMainframes are computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term probably had originated from the early mainframes, as...
s) were aimed for office and small business use.
WorkstationA 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. Workstations are still used for tasks such as
computer-aided designComputer-aided design is the use of computer technology for the design of objects, real or virtual. CAD often involves more than just shapes...
, drafting and modelling, computation-intensive scientific and engineering calculations, image processing,
architecturalFor a topical guide to this subject, see Outline of architecture. Architecture is the art and science of designing and constructing buildings and other physical structures for human shelter or use....
modelling, and
computer graphicsComputer graphics are graphics created using computers and, more generally, the representation and manipulation of pictorial data by a computer....
for animation and motion picture visual effects.
Eventually due to the IBM-PC's influence on the Personal Computer market Personal Computers and Home Computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of a few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of the personal computers used at home.
Market and sales
In 2001 125
millionOne million or one thousand thousand, is the natural number following 999,999 and preceding 1,000,001. The name is derived from Italian, where mille was 1,000, and 1,000,000 became milione, "a large thousand"....
personal computers were shipped in comparison to 48 thousand in 1977. More than 500 million personal computers were in use in 2002 and one billion personal computers had been sold worldwide since mid-1970s until this time. Of the latter figure, 75 percent were professional or work related, while the rest sold for personal or home use. About 81.5 percent of personal computers shipped had been
desktop computerA 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. Prior to the wide spread of microprocessors, a computer that could fit on a desk was considered remarkably small...
s, 16.4 percent
laptopA laptop is a personal computer designed for mobile use and small and light enough to sit on one's lap while in use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device , speakers, and often including a battery, into a single...
s and 2.1 percent
serverA server is an application running on a computer that delivers a service. For example, a web server will deliver web pages when requested by a browser . The way a server and a client dialogs is called a protocol...
s. United States had received 38.8 percent (394 million) of the computers shipped, Europe 25 percent and 11.7 percent had gone to Asia-Pacific region, the fastest-growing market as of 2002. The second billion was expected to be sold by 2008. Almost half of all the households in
Western EuropeWestern Europe is the collection of countries in the westernmost region of Europe, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a cultural entity—the region lying west of Central Europe...
had a personal computer and a computer could be found in 40 percent of homes in United Kingdom, compared with only 13 percent in 1985.
The global personal computer shipments were 264 million units in the year 2007, according to
iSuppliiSuppli Corporation is a market research and consulting firm specialized in the electronics value chain. With its applied market intelligence services, linking all segments of the electronics industry by monitoring the status of the electronics industry value chain, and continuously update a score...
, up 11.2 percent from 239 million in 2006.. In year 2004, the global shipments was 183 million units, 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.
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 EuropeWestern Europe is the collection of countries in the westernmost region of Europe, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a cultural entity—the region lying west of Central Europe...
and Japan accounted for 58 percent of the worldwide installed PCs. The emerging markets were expected to double their installed PCs by 2013 and to take 70 percent of the second billion PCs. About 180 million computers (16 percent of the existing installed base) were expected to be replaced and 35 million to be dumped into landfill in 2008. The whole installed base grew 12 percent annually.
In the developed world, there has been a vendor tradition to keep adding functions to maintain high prices of personal computers. However, since the introduction of One Laptop per Child foundation and its low-cost
XO-1The 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
netbookNetbooks are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access...
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.
Average selling price
For
Microsoft WindowsMicrosoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces...
systems, the
average selling priceThe 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
netbookNetbooks are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access...
s, drawing $569 for
desktop computerA 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. Prior to the wide spread of microprocessors, a computer that could fit on a desk was considered remarkably small...
s and $689 for
laptopA laptop is a personal computer designed for mobile use and small and light enough to sit on one's lap while in use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device , speakers, and often including a battery, into a single...
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.
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 networkA local area network is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport...
and run multi-user
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
s.
Desktop computer
Prior to the wide spread of PCs a computer that could fit on a
deskA 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 caseA computer case is the enclosure that contains the main components of a computer...
. Desktop computers come in a variety of styles ranging from large vertical tower cases to
small form factorSmall Form Factor is a generic term originally phrased as shuttle form factor, and originally meant to describe shoebox-sized personal computers with exactly two expansion slots...
models that can be tucked behind an LCD monitor. In this sense, the term 'desktop' refers specifically to a horizontally-oriented case, usually intended to have the display screen placed on top to save space on the desk top. Most modern desktop computers have separate screens and keyboards.
Single unit
Single unit PCs (also known as all-in-one PCs) are a subtype of desktop computers, which combine the monitor and case of the computer within a single unit. The monitor almost always utilizes a
touchscreenA touchscreen is a display that can detect the presence and location of a touch within the display area. The term generally refers to touch or contact to the display of the device by a finger or hand. Touchscreens can also sense other passive objects, such as a stylus. However, if the object...
as an optional method of user input, however detached keyboards and mice are normally still included. The inner components of the PC are often located directly behind the monitor.
Nettop
A subtype of desktops, called nettops, was introduced by Intel in February 2008 to describe low-cost, lean-function, desktop computers. A similar subtype of laptops (or notebooks) are the
netbookNetbooks are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access...
s (see below). These feature the new
Intel AtomIntel 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, and MIDs. The Atom Z series is code-named Silverthorne and the Atom N series is code-named Diamondville. As of June 2009, the most used chips in...
processor which specially enables them to consume less power and to be built into small enclosures.
Laptop
A laptop computer or simply
laptopA laptop is a personal computer designed for mobile use and small and light enough to sit on one's lap while in use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device , speakers, and often including a battery, into a single...
, also called a notebook computer or sometimes a notebook, is a small personal computer designed for mobility. Usually all of the interface hardware needed to operate the laptop, such as
parallelA parallel port is a type of interface found on computers for connecting various peripherals. It is also known as a printer port or Centronics port. The IEEE 1284 standard defines the bi-directional version of the port....
and
serial portIn 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
batteriesAn electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial...
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 that, due to the size and configuration of components, relatively little can be done to upgrade the overall computer from its original design. Some devices can be attached externally through ports (including via USB), however internal upgrades are not recommended or in some cases impossible, making the desktop PC more modular.
A subtype of notebooks, called
subnotebookA subnotebook or ultraportable is a class of laptop computers that are smaller and lighter than typical notebooks.This category of computers can range in price from high end high capability models at $2,000 to low end low capability models at $250.These computers are often confused with the...
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 PCIn personal computers, Ultra-Mobile PC is a term for a small form factor and specification for tablet PCs. Originally codenamed Project Origami, the project was launched in 2006 as a collaboration between Microsoft, Intel, Samsung, and a few others.- History :In February 2006, a viral marketing...
s (UMPC) are usually considered subnotebooks, or more specifically, subnotebook
Tablet PCIn general terms, tablet PC refers to a laptop or slate-shaped mobile computer, equipped with a touchscreen or graphics tablet/screen hybrid to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse....
s (see below).
NetbookNetbooks are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access...
s are sometimes considered in this category, though they are sometimes separated in a category of their own (see below).
Desktop replacements, meanwhile, are large laptops meant to replace a desktop computer while keeping the mobility of a laptop.
Netbook
NetbookNetbooks are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access...
s are small portable computers in a "clamshell" design, that are designed specifically for wireless communication and access to the Internet. They are generally much lighter and cheaper than
subnotebookA subnotebook or ultraportable is a class of laptop computers that are smaller and lighter than typical notebooks.This category of computers can range in price from high end high capability models at $2,000 to low end low capability models at $250.These computers are often confused with the...
s, and have a smaller display, between 7" and 9", with a screen resolution between 800x600 and 1024x768 but newer models feature higher resolution at up to 1280x768 like the Gigabyte M912X netbook. The operating systems and applications on them are usually specially modified so they can be comfortably used with a smaller sized screen, and the
OSAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
was in the start
LinuxLinux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed,...
, although most netbooks run one of the
NTWindows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was originally designed to be a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was...
version, Windows XP or Windows Vista (For example Sony's Tablet Netbook). Netbooks Have built in Wireless connectivity (
Wi-FiWi-Fi is a trademark of the Wi-Fi Alliance for certified products based on the IEEE 802.11 standards. This certification warrants interoperability between different wireless devices....
).
Some even have smaller but faster solid state storage systems instead of mechanical hard-disks. Storage capacities were usually in the 4 to 16 GB for solid state flash drives range but have largely increased with mechanical drives, expanding up to 160GB for example the Gigabyte M912X and the MSI WInd U100 with units that have mechanical hard drives instead of solid state flash drives. One of the first examples of such a system was the original Eee PC.
The emergence of new market segment of small, energy-efficient and low-cost devices designed for access to the Internet (
netbookNetbooks are a rapidly evolving category of small, light and inexpensive laptop computers suited for general computing and accessing web-based applications; they are often marketed as "companion devices," that is, to augment a user's other computer access...
s and nettops) could threaten established companies like
MicrosoftMicrosoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices...
, Intel, HP or
DellDell, Inc. develops, manufactures, sells, and supports personal computers and other computer-related products. Based in Round Rock, Texas, Dell employs more than 76,500 people worldwide ....
, analysts said in July 2008. A market research firm
International Data CorporationInternational Data Corporation is a market research and analysis firm specializing in information technology, telecommunications and consumer technology. IDC is a subsidiary of International Data Group...
predicted that the category could grow from fewer than 500,000 in 2007 to 9
millionOne million or one thousand thousand, is the natural number following 999,999 and preceding 1,000,001. The name is derived from Italian, where mille was 1,000, and 1,000,000 became milione, "a large thousand"....
in 2012 as the market for
low cost and secondhand computersInformation and Communication Technologies for Development is a general term referring to the application of Information and Communication Technologies within the field of socioeconomic development or international development. ICT4D concerns itself with directly applying information technology...
expands in developed economies. Also, after Microsoft ceased selling consumer versions of
Windows XPWindows XP is a line of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, and media centers. The name "XP" is short for "eXPerience"...
, it made an exception and continued to offer the
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
for netbook and nettop makers.
Tablet PC
A tablet PC is a
notebookA notebook is a book, made of paper or computer based, of which various uses can be made, including writing, drawing, and scrapbooking.-Paper Notebooks:...
or slate-shaped mobile computer, first introduced by
Pen computingPen computing refers to a computer user-interface using a pen and tablet, rather than devices such as a keyboard and a mouse.Pen computing is also used to refer to the usage of mobile devices such as wireless tablet PCs, PDAs and GPS receivers. The term has been used to refer to the usage of any...
in the early 90s with their PenGo Tablet Computer and popularized by
MicrosoftMicrosoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices...
. Its
touchscreenA touchscreen is a display that can detect the presence and location of a touch within the display area. The term generally refers to touch or contact to the display of the device by a finger or hand. Touchscreens can also sense other passive objects, such as a stylus. However, if the object...
or graphics tablet/screen hybrid technology allows the user to operate the
computerA computer is a machine that manipulates data according to a set of instructions.Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century . These were the size of a large room, consuming as...
with a
stylusA stylus is a writing utensil. The word is also used for a computer accessory . It usually refers to a narrow elongated staff, similar to a modern ballpoint pen. Many styluses are heavily curved to be held more easily...
or digital pen, or a fingertip, instead of a keyboard or
mouseIn 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...
. 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.
As technology and functionality continue to progress, prototype tablet PC's will continue to emerge. The Microsoft Courier, a personal business device, has two 7" monitors that support multi-touch gestures, Wi-Fi capabilities and has a built-in camera. The device looks to be a replacement to traditional planners while offering what most digital planners cannot, two pages and large writing spaces.
Ultra-Mobile PC
The ultra-mobile PC (UMPC) is a specification for a small
form factorForm factor may refer to:* Form factor or emissivity, the proportion of energy transmitted by that object which can be transferred to another object...
of
tablet PCIn general terms, tablet PC refers to a laptop or slate-shaped mobile computer, equipped with a touchscreen or graphics tablet/screen hybrid to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse....
s. It was developed as a joint development exercise by
MicrosoftMicrosoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices...
, Intel, and Samsung, among others. Current UMPCs typically feature the Windows XP, Windows Vista, Windows 7, or Linux
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
and low-voltage Intel
AtomThe atom is a basic unit of matter consisting 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.
Home theater PC
A home theater PC (HTPC) is a convergence device that combines the functions of a personal computer and a
digital video recorderA digital video recorder or personal video recorder is a device that records video in a digital format to a disk drive or other memory medium within a device. The term includes stand-alone set-top boxes, portable media players and software for personal computers which enables video capture and...
. It is connected to a
televisionTelevision is a widely used telecommunication medium for transmitting and receiving moving images, either monochromatic or color, usually accompanied by sound. "Television" may also refer specifically to a television set, television programming or television transmission...
or a television-sized
computer displayA monitor or display is a piece of electrical equipment which displays images generated by devices such as computers, without producing a permanent record. 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 centerThe term media center refers either to a dedicated computer appliance or to a specialized personal computer software, both of which are adapted for playing various kinds of media , and it usually has a Graphical user interface design to be used in living-room TV with a remote control...
systems or
media serverA media server is a computer appliance, ranging from an enterprise class machine providing video on demand, to, more commonly, a small home computer, or NAS , dedicated for storing various digital media .-Purpose:By definition a media server is a device that simply stores and shares media...
s. The general goal in a HTPC is usually to combine many or all components of a
home theaterA home theater Is a theater built in a home, designed to mimic commercial theater performance.*Home cinema*AV receiver, often referred to as home theater systems....
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
MythTVMythTV is a free Linux 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 Personal Computer...
,
Windows Media CenterWindows Media Center is an application with a 10-foot user interface designed to serve as a home-entertainment hub for the living-room TV. It is included in Windows XP Media Center Edition, which must be installed as an operating system, as the application cannot be added to an existing...
,
GB-PVRGB-PVR is a PVR application, running on Microsoft Windows, whose main function is scheduling TV recordings and playing back live TV...
,
SageTVSageTV Media Center is a proprietary, commercial digital video recording software package for Mac OS X, Windows and Linux. It requires that the host PC have a hardware based TV tuner card. The SageTV software has an integrated Electronic Programming Guide that is updated via the Internet...
, Famulent or
LinuxMCELinuxMCE 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...
.
Pocket PC
A pocket PC is a hardware specification for a handheld-sized
computerA computer is a machine that manipulates data according to a set of instructions.Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century . These were the size of a large room, consuming as...
(
personal digital assistantA personal digital assistant is a handheld computer, also known as a palmtop computer. Newer PDAs commonly have color screens and audio capabilities, enabling them to be used as mobile phones , web browsers, or portable media players. Many PDAs can access the Internet, intranets or extranets...
) that runs the
MicrosoftMicrosoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices...
Windows MobileWindows Mobile is a compact operating system developed by Microsoft, and designed for use in smartphones and mobile devices.It is based on Windows CE, and features a suite of basic applications developed using the Microsoft Win32 API. It is designed to be somewhat similar to desktop versions of...
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
. It may have the capability to run an alternative
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
like
NetBSDNetBSD is a freely redistributable, open source version of the Unix-derivative Berkeley Software Distribution computer operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed...
or
LinuxLinux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed,...
. It has many of the capabilities of modern desktop
PCsIBM 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
freewareFreeware is computer software that is available for use at no cost or for an optional fee.The opposite of Freeware is Payware.-History:...
. Some of these devices also include
mobile phoneA mobile phone or mobile is a long-range, electronic device used for mobile telecommunications...
features. Microsoft compliant Pocket PCs can also be used with many other add-ons like
GPS receiversThe Global Positioning System is a U.S. space-based global navigation satellite system. It provides reliable positioning, navigation, and timing services to worldwide users on a continuous basis in all weather, day and night, anywhere on or near the Earth.GPS is made up of three parts: between 24...
,
barcodeA barcode is an optical machine-readable representation of data. Originally, barcodes represented data in the widths and the spacings of parallel lines, and may be referred to as linear or 1D barcodes or symbologies...
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
A typical hardware setup of a
desktop computerA 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. Prior to the wide spread of microprocessors, a computer that could fit on a desk was considered remarkably small...
consists of:
- computer case
A computer case is the enclosure that contains the main components of a computer...
with power supply
- central processing unit
The Central Processing Unit or processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. This term has been in use in the computer industry at least since the early 1960s...
(processor)
- motherboard
A motherboard is the central printed circuit board in many modern computers, and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the main board, system board, or, on Apple computers, the logic...
- memory card
Computer memory refers to devices that are used to store data or programs on a temporary or permanent basis for use in an electronic digital computer. Computers represent information in binary code, written as sequences of 0s and 1s...
- hard disk
A hard disk drive is a non-volatile storage device that stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, "drive" refers to the motorized mechanical aspect that is distinct from its medium, such as a tape drive and its tape, or a floppy disk...
- video card
A video card, video adapter, graphics-accelerator card, display adapter, or graphics card is an expansion card whose function is to generate and output images to a display...
- visual display unit (monitor)
- optical disc
In computing and optical recording, an optical disc or optical disk is a flat, usually circular, disc which can contain audio, video or data encoded in microscopic pits on a special material on one of its flat surfaces...
(usually DVD-ROM or DVD WriterDVD recordable and DVD rewritable refer to DVD optical disc formats that can be recorded , either write once or rewritable format written by laser, as compared to DVD-ROM, which is mass-produced by pressing...
)
- keyboard and pointing device
A pointing device is an input interface that allows a user to input spatial data to a computer...
These components can usually be put together with little knowledge to build a computer. The motherboard is a main part of a computer that connects all devices together. The memory card(s), graphics card and processor are mounted directly onto the motherboard (the processor in a
socketA CPU socket or CPU slot is an electrical component that attaches to a printed circuit board and is designed to house a CPU . It is a special type of integrated circuit socket designed for very high pin counts...
and the memory and graphics cards in expansion slots). The mass storage is connected to it with cables and can be installed in the computer case or in a separate case. This is the same for the keyboard and mouse, except that they are external and connect to the 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.
Several functions (implemented by
chipsetA chipset or chip set refers to a group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product.- Computers :...
s) can be integrated into the motherboard, typically USB and network, but also graphics and sound. Even if these are present, a separate card can be added if what is available isn't sufficient. The graphics and sound card can have a break out box to keep the analog parts away from the
electromagnetic radiationElectromagnetic radiation is a ubiquitous phenomenon that takes the form of self-propagating waves in a vacuum or in matter. It consists of electric and magnetic field components which oscillate in phase perpendicular to each other and perpendicular to the direction of energy propagation...
inside the computer case. For really large amounts of data, a
tape driveA tape drive, which is also known as a streamer, is a data storage device that reads and writes data stored on a magnetic tape. It is typically used for archival storage of data stored on hard drives...
can be used or (extra) hard disks can be put together in an external case.
The
hardwareA personal computer is made up of multiple physical components of computer hardware, upon which can be installed an operating system and a multitude of software to perform the operator's desired functions.-Typical PC hardware:...
capabilities of personal computers can sometimes be extended by the addition of
expansion cardAn expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard to add additional functionality to a computer system....
s connected via an expansion
busIn computer architecture, a bus is a subsystem that transfers data between computer components inside a computer or between computers.Early computer buses were literally parallel electrical buses with multiple connections, but the term is now used for any physical arrangement that provides the...
. Some standard peripheral buses often used for adding expansion cards in personal computers as of 2005 are
PCIConventional PCI is a computer bus for attaching hardware devices in a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a slot...
,
AGPThe 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 ExpressPCI Express , officially abbreviated as PCIe , is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP standards...
. Most personal computers as of 2005 have multiple physical
PCIConventional PCI is a computer bus for attaching hardware devices in a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a slot...
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.
Computer case
A computer case is the enclosure that contains the main components of a
computerA computer is a machine that manipulates data according to a set of instructions.Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century . These were the size of a large room, consuming as...
. Cases are usually constructed from
steelSteel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese, chromium, vanadium, and tungsten...
,
aluminiumAluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13. It is not soluble in water under normal circumstances....
, or
plasticPlastic is the general common term for a wide range of synthetic or semisynthetic organic amorphous solid materials suitable for the manufacture of industrial products...
, although other materials such as
woodWood is an organic material; in the strict sense wood is produced as secondary xylem in the stems of trees . In a living tree it transfers water and nutrients to the leaves and other growing tissues, and has a support function, enabling woody plants to reach large sizes or to stand up for themselves...
, plexiglas or
fansA computer fan is any fan inside 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...
have also been used in case designs. 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
motherboardA motherboard is the central printed circuit board in many modern computers, and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the main board, system board, or, on Apple computers, the logic...
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
bladeA blade server is a stripped down server computer with a modular design optimized to minimize the use of physical space. 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 consumption and...
serversA server is an application running on a computer that delivers a service. For example, a web server will deliver web pages when requested by a browser . The way a server and a client dialogs is called a protocol...
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
ATXATX is a computer form factor designed by Intel in 1995. It was the first big change in computer case, motherboard, and power supply design in many years. ATX overtook AT completely as the default form factor for new systems. ATX addressed many of the AT form factor's annoyances that had...
, although
microATXmicroATX, also known as µATX is a small form factor standard for motherboards that was introduced in December of 1997. The maximum size of a microATX motherboard is 9.6 inches x 9.6 inches , but some microATX boards can be as small as 6.75 inches by 6.75 inches...
and
small form factorSmall Form Factor is a generic term originally phrased as shuttle form factor, and originally meant to describe shoebox-sized personal computers with exactly two expansion slots...
s have become very popular for a variety of uses. Companies like
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
AOpenAcer Incorporated is a Taiwan-based multinational electronics manufacturer. Its product lineup includes desktops and laptops, as well as personal digital assistants , servers and storage, displays, peripherals, and e-business services for business, government, education, and home users.Acer is...
have popularized small cases, for which
FlexATXFlexATX 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.
Central processing unit
The central processing unit, or CPU, is that part of a computer which executes software
programComputer programs are instructions for 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 the instructions...
instructions. In older computers this circuitry was formerly on several
printed circuit boardA printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring board...
s, but in PCs is a single integrated circuit. Nearly all PCs contain a type of CPU known as a
microprocessorA microprocessor incorporates most or all of the functions of a central processing unit on a single integrated circuit . The first microprocessors emerged in the early 1970s and were used for electronic calculators, using binary-coded decimal arithmetic on 4-bit words...
. The microprocessor often plugs into the motherboard using one of many different types of sockets.
IBM PC compatibleIBM 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 TechnologiesVIA 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
TransmetaTransmeta 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...
. Apple Macintosh computers were initially built with the
MotorolaMotorola, Inc. is an American, multinational, Fortune 100, telecommunications company based in Schaumburg, Illinois. It is a manufacturer of wireless telephone handsets, and also designs and sells wireless network infrastructure equipment such as cellular transmission base stations and signal...
680x0 family of processors, then switched to the
PowerPCPowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM. Originally intended for personal computers, PowerPC CPUs have since become popular embedded and high-performance processors...
series (a RISC architecture jointly developed by
Apple ComputerApple Inc. is an American multinational corporation that designs and manufactures consumer electronics and computer software products. The company's best-known hardware products include Macintosh computers, the iPod and the iPhone...
,
IBMInternational Business Machines Corporation, abbreviated IBM, is a multinational computer technology and IT consulting corporation headquartered in Armonk, Town of North Castle, New York, United States. The company is one of the few information technology companies with a continuous history dating...
and
MotorolaMotorola, Inc. is an American, multinational, Fortune 100, telecommunications company based in Schaumburg, Illinois. It is a manufacturer of wireless telephone handsets, and also designs and sells wireless network infrastructure equipment such as cellular transmission base stations and signal...
), but as of 2006, Apple switched again, this time to x86-compatible processors by Intel. Modern CPUs are equipped with a
fanA computer fan is any fan inside 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 sinkA heat sink is an environment or object that absorbs and dissipates heat from another object using thermal contact...
.
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 circuitIn electronics, an integrated circuit is a miniaturized electronic circuit that has been manufactured in the surface of a thin substrate of semiconductor material...
s (ICs) - providing the interface between the
CPUThe Central Processing Unit or processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. This term has been in use in the computer industry at least since the early 1960s...
memory and input/output peripheral circuits, main memory, and facilities for initial setup of the computer immediately after power-on (often called boot
firmwareIn electronics and computing, firmware is a term often used to denote the fixed, usually rather small, programs and data structures that internally control various electronic devices...
or, in IBM PC compatible computers, a
BIOSIn IBM PC Compatible computers, the basic input/output system , also known as the System BIOS, is a de facto standard defining a firmware interface. The BIOS is boot firmware, designed to be the first code run by a PC when powered on...
). 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
semiconductorA semiconductor is a material that has an electrical resistivity between that of a conductor and an insulator, that is, generally in the range 10
3 Siemens/cm to 10
−8 S/cm. Devices made from semiconductor materials are the foundation of modern electronics, including radio,...
random access memory (RAM) of various kinds such as
DRAMDynamic random access memory is a type of random access memory that stores each bit of data in a separate capacitor within an integrated circuit. Since real capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically...
or
SRAMStatic 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 diskA hard disk drive is a non-volatile storage device that stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, "drive" refers to the motorized mechanical aspect that is distinct from its medium, such as a tape drive and its tape, or a floppy disk...
s or
optical discIn computing and optical recording, an optical disc or optical disk is a flat, usually circular, disc which can contain audio, video or data encoded in microscopic pits on a special material on one of its flat surfaces...
s, but is usually
volatileVolatile 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 memoryFlash memory is a non-volatile computer storage that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products...
has dropped in cost, the prevailing form of mass storage in personal computers is still the
hard diskA hard disk drive is a non-volatile storage device that stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Strictly speaking, "drive" refers to the motorized mechanical aspect that is distinct from its medium, such as a tape drive and its tape, or a floppy disk...
.
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-RWA 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...
s, and various optical disc recorders may all be added by the user to certain PCs. Standard internal storage device connection interfaces are
PATA-Mathematics and science:* Parallel , an imaginary east-west line circling a globe* Parallel circuits, as opposed to series* Parallel * Parallel evolution* Parallel transport-Music and entertainment:...
,
Serial ATAThe serial ATA, or SATA computer bus, is a storage-interface for connecting host bus adapters to mass storage devices such as hard disk drives and optical drives. The SATA host adapter is integrated into almost all modern consumer laptop computers and desktop motherboards.Serial ATA was designed...
,
SCSISmall Computer System Interface, or SCSI , 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...
Video card
The
video cardA video card, video adapter, graphics-accelerator card, display adapter, or graphics card is an expansion card whose function is to generate and output images to a display...
- otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the
computer displayA monitor or display is a piece of electrical equipment which displays images generated by devices such as computers, without producing a permanent record. 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
PCIConventional PCI is a computer bus for attaching hardware devices in a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a slot...
,
AGPThe 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 ExpressPCI Express , officially abbreviated as PCIe , is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP 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 equipmentElectrical 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
imageAn 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....
s generated by a
computerA computer is a machine that manipulates data according to a set of instructions.Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century . These were the size of a large room, consuming as...
without producing a permanent record. The word "monitor" is used in other contexts; in particular in television broadcasting, where a
televisionTelevision is a widely used telecommunication medium for transmitting and receiving moving images, either monochromatic or color, usually accompanied by sound. "Television" may also refer specifically to a television set, television programming or television transmission...
picture is displayed to a high standard. A computer display device is usually either a
cathode ray tubeThe cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen, with internal or external means to accelerate and deflect the electron beam, used to create images in the form of light emitted from the fluorescent screen...
or some form of flat panel such as a
TFT LCDA 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,
circuitryAn electronic circuit is a closed path or paths formed by the interconnection of electronic components through which an electric current can flow....
to generate a picture from
electronicElectronics is a branch of science and technology that deals with the controlled flow of electrons. The ability to control electron flow is usually applied to information handling or device control. Electronics is distinct from electrical science and technology, which deals with the generation,...
signalsIn 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
enclosureAn 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 cardAn expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard to add additional functionality to a computer system....
, there is circuitry to convert internal
dataIn computer science, data is anything in a form suitable for use with a computer. Data is often distinguished from programs. A program is a set 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 interfaceA graphical user interface is a type of user interface item that allows people to interact with programs in more ways than typing such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment with images rather than...
s emerged and became common, they began to display more images and multimedia content.
Keyboard
In computing, a
keyboardIn computing, a keyboard is an input device, partially modeled after the typewriter keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. A keyboard typically has characters engraved or printed on the keys and each press of a key typically...
is an arrangement of buttons that each correspond to a function, letter, or number. They are the primary devices of inputing text. In most cases, they contain an aray 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
QWERTYQWERTY is the most used modern-day keyboard layout on English-language computer and typewriter keyboards. It takes its name from the first six characters seen in the far left of the keyboard's top row of letters...
layout, which was originally used in
typewriterA typewriter is a mechanical or electromechanical device with a set of "keys" that, when pressed, cause characters to be printed on a medium, usually paper...
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 inputing characters with accents or opening a task manager. Programs use keyboard shotcuts very differently and all use different keyboard shortcuts for different program specific operations, such as refreshing a
web pageA webpage or web page is a document or resource of information that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a computer screen....
in a
web browserA 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
MouseIn 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, slidable device that users hold and slide around to point at, click, 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; 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 the wheel using their fingers to "scroll" up or down. The scroll wheel can also be pressed down, and therefore be used as a third button. 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.
Mice traditionally detected movement and communicated with the computer with an internal "mouse ball"; and use 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 and accuracy. Modern mice use optical technology to directly trace movement of the surface under the mouse and are much more accurate and durable. 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 5 1/4 inch and 3 1/2 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 driveThe Zip drive is a medium-capacity removable disk storage system, introduced by Iomega in late 1994. Originally, Zip disks launched with capacities of only 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
DVDDVD, also known as Digital Versatile Disc or Digital Video Disc,is an optical disc storage media format, and was founded in 1995. Its main uses are video and data storage...
and
Blu-ray DiscBlu-ray Disc is an optical disc storage medium designed to supersede the standard DVD format. Its main uses are for storing high-definition video, PlayStation 3 games, and other data, with up to 25 GB per single layered, and 50 GB per dual layered disc...
, 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.
Early
home computerHome computer was a class of personal computer entering the market in 1977 and becoming increasingly common during the 1980s. They were marketed to consumers as accessible personal computers, more capable than video game consoles...
s used
compact audio cassettesThe Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. Although originally designed for dictation, improvements in fidelity led the Compact Cassette to supplant reel-to-reel tape recording in most...
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 recorderThe videocassette recorder , is a type of video tape recorder that uses removable videotape cassettes containing magnetic tape to record audio and video from a television broadcast so it can be played back later...
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 readerA memory card reader is a device used for communication with a smart card or a flash memory card.A business card reader is a scanning device used to scan and electronically save business cards....
, which often is compatible with several forms of
flash memoryFlash memory is a non-volatile computer storage that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products...
. 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 driveA USB flash drive consists of flash memory data storage device integrated with a USB 1.1 or 2.0 interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk, and most weigh less than 1 ounce...
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 systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
(e.g.:
Microsoft WindowsMicrosoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces...
,
Mac OSMac OS is the trademarked name for 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...
,
LinuxLinux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed,...
or many others) can be located on any storage, but typically it is on a hard disks. A
Live CDA live CD or live DVD 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
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 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
Although other network technologies exist, Ethernet has achieved near-ubiquity since the mid-1990s. Every Ethernet network card has a unique 48-bit serial number called a MAC address, which is stored in ROM carried on the card. Every computer on an Ethernet network must have a card with a unique...
- Router
A router is a networking device whose software and hardware are usually tailored to the tasks of routing and forwarding information. For example, on the Internet, information is directed to various paths by routers....
Common
peripheralA peripheral is a device attached to a host computer but not part of it whose primary functionality is dependent upon the host, and can therefore be considered as expanding the host's capabilities, while not forming part of the system's core architecture....
s and adapter cards
- Headset
Headset may refer to:*Headphones , this refers to a set of headphones including a microphone attachment*Headset *Headset *Headset , an electronica / hip-hop group...
- 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 are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer...
- Microphone
A microphone, colloquially called a mic or mike , is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1876, Emile Berliner invented the first microphone used as a telephone voice transmitter...
- Printer
In computing, a printer is a peripheral which produces a hard copy 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 newer printers, a USB...
- Scanner
Scanner may refer to a number of technological devices:* Scanner , for searching for and receiving radio broadcasts* A rotating radar antenna* Image scanner, which digitizes a two-dimensional image...
- Sound adapter card
A sound card is a computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or...
as a separate card rather than located on the motherboard
- Speaker
A loudspeaker is an electroacoustic transducer that converts an electrical signal into sound. The speaker pulses in accordance with the variations of an electrical signal and causes sound waves to propagate through a medium such as air or water.Loudspeakers are the most variable elements in a...
s
- Webcam
A webcam is a video capture device connected to a computer or computer network, often using a USB port or, if connected to a network, ethernet or Wi-Fi....
Software
Computer software is a general term used to describe a collection of
computer programComputer programs are instructions for 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 the instructions...
s, procedures and documentation that perform some tasks on a computer system.
The term includes
application softwareApplication software is a computer program that functions and is operated by means of a computer, with the purpose of supporting or improving the software user's work. In other words, it is the subclass of computer software that employs the capabilities of a computer directly and thoroughly to a...
such as
word processorA word processor is a computer application used for the production of any sort of printable material....
s which perform productive tasks for users,
system softwareSystem software is closely related to, but distinct from Operating System software. It is any computer software that provides the infrastructure over which programs can operate, i.e. it manages and controls computer hardware so that application software can perform...
such as
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
s, which interface with
hardwareHardware is a general term for the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware....
to provide the necessary services for application software, and
middlewareMiddleware is computer software that connects software components or 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 systemsDistributed 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 processingWord 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:...
,
InternetThe Internet is a global system of interconnected computer networks that use the standardized Internet Protocol Suite to serve billions of users worldwide...
browsing,
Internet faxInternet fax uses the internet to receive and send faxes.Internet faxing is a general term which refers to sending a document facsimile using the Internet, rather than using only phone networks ....
ing,
e-mailElectronic mail, often abbreviated as email or e-mail, is a method of exchanging digital messages, designed primarily for human use...
and other digital messaging,
multimediaMultimedia 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 only use traditional forms of printed or hand-produced material...
playback, computer game play and
computer programmingComputer programming is the process of writing, testing, debugging/troubleshooting, and maintaining the source code of computer programs. This source code is written in a programming language. The code may be a modification of an existing source or something completely new...
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-friendlinessUsability is a term used to denote the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal...
" in mind. However, the
software industryThe 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
computerA computer is a machine that manipulates data according to a set of instructions.Although mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century . These were the size of a large room, consuming as...
resources and provides programmers with an
interfaceThe user interface is the aggregate of means by which people—the users—interact with the system—a particular machine, device, computer program or other complex tool...
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 outputIn 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 networkingComputer networking is the engineering discipline concerned with communication between computer systems or devices. Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs...
and managing files.
Common contemporary desktop OSes are
Microsoft WindowsMicrosoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces...
(92.77% market share),
Mac OS XMac OS X is a line of computer operating systems developed, marketed, and sold by Apple Inc., and since 2002 has been included with all new Macintosh computer systems...
(5.12%),
LinuxLinux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed,...
(0.95%), Solaris and
FreeBSDFreeBSD is a free Unix-like operating system descended from AT&T UNIX via the Berkeley Software Distribution . It has been characterized as "the unknown giant among free operating systems". It is not a clone of UNIX, but works like UNIX, with UNIX-compliant internals and system APIs. FreeBSD is...
. 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
UnixUnix is a 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.
UnixUnix is a 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 LabsBell Laboratories is the research and development organization of Alcatel-Lucent and previously of the American Telephone & Telegraph Company .Bell Laboratories has had its headquarters at Murray Hill, New Jersey, and it has research and development facilities...
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 systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
s by
MicrosoftMicrosoft Corporation is a multinational computer technology corporation that develops, manufactures, licenses, and supports a wide range of software products for computing devices...
. Microsoft first introduced an operating environment named
Windows in November 1985 as an add-on to
MS-DOSMS-DOS is an operating system developed by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the main operating system for personal computers during the 1980s. It was preceded by M-DOS , designed and copyrighted by Microsoft in 1979...
in response to the growing interest in
graphical user interfaceA graphical user interface is a type of user interface item that allows people to interact with programs in more ways than typing such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment with images rather than...
s (GUIs). The most recent client version of Windows is
Windows VistaWindows Vista is a line of operating systems developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...
and the current server version is Windows Server 2008. The upcoming client and server versions of Windows, Windows 7 and
Windows Server 2008 R2Windows Server 2008 R2 is a server operating system produced by Microsoft. It is to be released on October 22, 2009. According to the Windows Server Team blog, the retail availability is September 14, 2009. It is built on Windows NT 6.1, the same core operating system used with the end-user...
, are scheduled to be available at retail from October 22, 2009.
Linux
Linux is a family of
Unix-likeA 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 systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
s. Linux is one of the most prominent examples of
free softwareFree 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 minimal restrictions only to ensure that further recipients can also...
and
open sourceOpen source is an approach to the design, development, and distribution of software, offering practical accessibility to a software's source code. Some consider open source as one of various possible design approaches, while others consider it a critical strategic element of their operations...
development: typically all underlying
source codeIn computer science, source code is any collection of statements or declarations written in some human-readable computer programming language...
can be freely modified, used, and redistributed by anyone. The name "Linux" comes from the
Linux kernelThe 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 TorvaldsLinus Benedict Torvalds is a Finnish software engineer best known for having initiated the development of the Linux kernel...
. The system's utilities and
librariesIn computer science, a library is a collection of subroutines or classes used to develop software. Libraries contain code and data that provide services to independent programs. This allows the sharing and changing of code and data in a modular fashion. Some executables are both standalone programs...
usually come from the
GNUGNU is a computer operating system composed entirely of free software. Its name is a recursive acronym for “GNU's not Unix!” This name was chosen because GNU's design is Unix-like, but differs from Unix by being free software and containing no Unix code...
operating system, announced in 1983 by
Richard StallmanRichard Matthew Stallman , often abbreviated "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 nameThe 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.
Predominantly known for its use in
serverA server is an application running on a computer that delivers a service. For example, a web server will deliver web pages when requested by a browser . The way a server and a client dialogs is called a protocol...
s, Linux is supported by corporations such as
DellDell, Inc. develops, manufactures, sells, and supports personal computers and other computer-related products. Based in Round Rock, Texas, Dell employs more than 76,500 people worldwide ....
,
Hewlett-PackardHewlett-Packard Company , commonly referred to as HP, is a technology corporation headquartered in Palo Alto, California, United States. HP has its United States offices at the former old Compaq Campus in unincorporated Harris County, Texas, Latin America offices in Miami-Dade County, Florida,...
,
IBMInternational Business Machines Corporation, abbreviated IBM, is a multinational computer technology and IT consulting corporation headquartered in Armonk, Town of North Castle, New York, United States. The company is one of the few information technology companies with a continuous history dating...
,
NovellNovell, Inc. is a global software corporation based in the United States specializing in enterprise operating systems such as SUSE Linux Enterprise and Novell NetWare; identity, security and systems management solutions; and collaboration solutions. Together with WordPerfect, Novell was...
,
Oracle CorporationOracle Corporation specializes in developing and marketing enterprise software products — particularly database management systems. Through organic growth and a number of high-profile acquisitions, Oracle enlarged its share of the software market...
,
Red HatRed 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. is a private company founded by South African entrepreneur Mark Shuttleworth for the promotion of free software projects...
and
Sun MicrosystemsSun Microsystems, Inc. is a multinational vendor of computers, computer components, computer software, and information technology services, founded on February 24, 1982...
. It is used as an operating system for a wide variety of computer
hardwareHardware is a general term for the physical artifacts of a technology. It may also mean the physical components of a computer system, in the form of computer hardware....
, including
desktop computerA 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. Prior to the wide spread of microprocessors, a computer that could fit on a desk was considered remarkably small...
s, supercomputers, video game systems, such as the
PlayStation 3The PlayStation 3 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...
, several arcade games, and embedded devices such as
mobile phoneA mobile phone or mobile is a long-range, electronic device used for mobile telecommunications...
s, routers, and
stage lightingModern 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....
systems.
Mac OS X
Mac OS X is a line of graphical
operating systemAn operating system is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine. As a host, one of the purposes of an operating...
s developed, marketed, and sold by Apple Inc.. Mac OS X is the successor to the original
Mac OSMac OS is the trademarked name for 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. Unlike its predecessors, Mac OS X is a
UnixUnix is a 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...
-based operating system. The most recent version of Mac OS X is Mac OS X 10.6 "Snow Leopard", and the current server version is
Mac OS X Server 10.6Mac OS X Server is Apple's UNIX server operating system. Based on the same architecture as Mac OS X, Mac OS X Server includes additional services, applications and administration tools for managing and deploying servers....
.
Applications
A computer user will apply application software to carry out a specific task.
System softwareSystem software is closely related to, but distinct from Operating System software. It is any computer software that provides the infrastructure over which programs can operate, i.e. it manages and controls computer hardware so that application software can perform...
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
analogyAnalogy is a cognitive process of transferring information 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 processorA word processor is a computer application used for the production of any sort of printable material....
s,
spreadsheetA spreadsheet is a computer application that simulates a paper worksheet. It displays multiple cells that together make up a grid consisting of rows and columns, each cell containing either alphanumeric text or numeric values...
s, and media players. Multiple applications bundled together as a package are sometimes referred to as an
application suite.
Microsoft OfficeMicrosoft Office is an office suite of interrelated desktop applications, servers and services for the Microsoft Windows and Mac OS X operating systems. Microsoft Office was introduced by Microsoft in 1989 for Mac OS, with a version for Windows in 1990...
and
OpenOffice.orgOpenOffice.org , commonly known as OpenOffice, is an office application suite available for a number of different computer operating systems. It is distributed as free software and written using its own GUI toolkit...
, 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 interfaceThe user interface is the aggregate of means by which people—the users—interact with the system—a particular machine, device, computer program or other complex tool...
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.
See also
- 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. Prior to the wide spread of microprocessors, a computer that could fit on a desk was considered remarkably small...
- 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
- Gaming PC
Enthusiast computing refers to a sub-culture of personal computer users who focus on extremely high-performance computers. Manufacturers of performance-oriented parts typically include an enthusiast model in their offerings...
- 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 field of socioeconomic development or international development. ICT4D concerns itself with directly applying information technology...
- List of computer system manufacturers
- 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, the museum has been completely renovated....
- 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
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....
- Supercomputer
A supercomputer is a computer that is at the frontline of current processing capacity, particularly speed of calculation. Supercomputers were introduced in the 1960s and were designed primarily by Seymour Cray at Control Data Corporation , and led the market into the 1970s until Cray left to form...
External links
- How Stuff Works pages:
- How to Build a Computer
- Low cost computer guide