Desktop computer
From Wikipedia, the free encyclopedia
A desktop computer is a personal computer made for use on a desk in an office or home and is distinguished from portable computers such as laptops or PDAs and specialized computers such as servers.
Desktops are currently the most affordable computers and ubiquitous in businesses, schools, and households; they are used for performing office tasks, organizing digital photos, video editing and Internet access. Nearly all desktop computers are modular, with components that can easily be replaced or upgraded.
Desktop computers come in a variety of case styles ranging from large vertical towers to small form factor models that can be tucked behind an LCD monitor.
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History
Desktop computers were widely produced throughout the late 1970s and 1980s. Originally they were named "microcomputers" to differentiate them from the mainframe and minicomputers that were traditionally available for sale by the major computer companies at the time. In 1975 the MITS Altair became the first pre-assembled desktop computer available on the market. However, due to the computer's design being geared more towards the hobbyist market the appeal of the machine was limited.
1977 saw the near-simultaneous release in the U.S. of three computers that equally deserve mention as the forerunners of today's desktop computer: the Apple II, the Commodore PET. and the Tandy TRS-80 computer. Each of these machines would be considered crude by today's standards; the TRS-80, for example, comprised a green phosphor 12" screen, an expansion box with 4 kilobytes of memory, a keyboard and a cassette recorder. It retailed for around £695.
Through the 1980s the desktop computer became more and more commonplace in society. Sales boomed as a wide spectrum of users, from the largest corporation down to the individual at home, found exciting new uses for the machines. However, it was not until the internet explosion in the mid-1990s that the desktop computer became nearly ubiquitous in our modern era.
Hardware
The hardware in a desktop computer is modular, making it easy for someone with intermediate knowledge of a computer to modify one. The internal hardware of a basic desktop computer consists of RAM, CPU, a motherboard, a graphics card and a sound card as well as additional onboard cards for Ethernet and other ports.
Desktop computers usually have a separate monitor, with a few exceptions such as Apple Computer's iMacs and eMacs and some Compaq desktops (the CDS series). User-input peripherals such as keyboards and mice are attached to the computer's ports, as well as other peripherals such as printers. Most of the functionality is contained within the case, but some components can be either external or internal (such as various storage devices or modems). The case is often placed on or under the desk. Sometimes, it can be placed underneath the monitor depending on the size and shape.
Desktop computers are generally more affordable than notebook computers. This is because no extra effort is needed to miniaturize the components, or to manufacture components that use up less power.
Components
- Fan - cools the computer. These are present on most computers.
- Motherboard - links all of the components together and routes data.
- Hard drive - long-term internal data storage.
- CD-ROM or DVD Drive - reads most or all types of CDs and/or DVDs.
- Processor.
- CPU Cooler - cools the processing unit. Typically a fan combined with a heatsink.
- RAM - short-term data storage.
- Graphics card - codes video output and delivers to monitor.
- Physics card - performs physics computations in some modern games.
- Sound card - codes sound output and delivers to speakers.
- Speakers - deliver sound.
- Modem - used to access data via a telephone line (dial-up connection). Used to access BBS and the Internet.
- Network card - allows the computer to be connected to a computer network where it can communicate with other computers. Also used as a means of accessing the Internet via a broadband connection.
- Power supply - distributes power to the various components.
- Floppy Drive - Reads and Writes floppy disks. Although largely supplanted by CDs and Flash Drives, is still common on many systems, and may be required during set-up on certain operating systems.
Ports
All desktop computers have ports which are used to plug external devices into the computer such as monitors, keyboards, printers and scanners.
- USB - Used for the majority of peripherals. Designed to be a universal connector, to be compatible with any device.
- Ethernet - Used for networking and broadband Internet connections.
- Modem - Used for data access via a telephone line (eg. dial-up Internet connections). Slowly being replaced by broadband connections as dial-up becomes an obsolete technology.
- Headphone jack - Used for connecting sound devices. (USB can also be used)
- Serial - Used for connecting any device that uses a serial connector. These are being replaced by USB.
- Parallel - Used for connecting any device that uses a parallel connector. These are being replaced by USB.
- PS/2 - Used for computer mice and keyboards (These are being replaced by USB)
- Video (VGA) - Used for connecting a monitor / projector with analog signal.
- Digital Video Interface (DVI) - Used for connecting a monitor, but keeps in the signal in digital format. Usually used for LCD displays.
- Power - Used for connecting the power lead.
- FireWire/IEEE 1394 - Used for connecting external hard drives and camcorders.
All-in-one
All-in-one computers are desktop computers that combine the monitor into the same case as the CPU. The term, "all-in-one" was initially associated with Digital Equipment Corporation's VAX "all-in-one" software which provided a common menu to choose: email, spreadsheet, database, file system, etc. The "mouse" had not been invented yet so everything was driven by the keyboard. The original Macintosh introduced in 1984 by Apple Computer was one of the first all-in-one computers, In 1998 Apple released the iMac which was also an all-in-one computer. These types of desktop computers save desk space, but are limited when it comes to expansion to improve their capabilities. PC manufacturers such as Gateway have also released all-in-one computers. Some PC and refrigerator manufacturers have even included full featured PCs and monitors in refrigerators which could be considered all-in-one.
