Desktop computer
A desktop computer is an independent personal computer that is made especially for use on a desk in an office or home. The term is used mainly to distinguish this type of personal computer from portable computers and laptops (or notebooks), but also to distinguish other types of computers like the PDA, server or mainframe.
Desktops are currently the most affordable and most common computers, and are frequently used by businesses, schools, households and other organizations; they are used not only to produce text documents, or pictures and video but also to communicate them. Nearly all modern desktop computers are modular, meaning that the components can easily be replaced or upgraded. An older term, desktop computer refers to a computer whose case is oriented horizontally (usually, the monitor is placed on top of the case). Such cases are called desktops as opposed to towers. But modern terminology also includes tower in the general umbrella desktop term.
History
Desktop computers were widely produced in the late 1970s and 1980s as there were no laptop or PDA computers available at the time. The first widely sold and successful desktop computer was the Apple II introduced in 1977 by Apple Computer. Also the Tandy TRS-80 computer which comprised a green phosphor 12" screen, an expansion box with 4k memory, a keyboard and a cassette. All this for only £695. Radio Shack, the American Tandy Corporation, put the TRS-80 up against Eniac and the Tandy beat the 30-year-old, extremely obsolete, computer.
In the mid 1990s desktop computers were widely advertised for their amount of power available for graphics and multimedia. Studios, universities and governments prefer to use desktop computers today because they are more powerful and more expandable than a laptop computer.
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. 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.
The IBM compatible desktop computer was far behind the competition from other manufacturers such as Radio Shack, Apple, Commodore, Atari, etc. However, they released their design for others to copy. This made it possible to buy brand X components and insert them into multiple brands of computers which all functioned the same and used the same operating system. Albert Clark used this to advantage and wrote the specifications for the first major government desktop purchase by specifying an IBM compatible instead of trying to justify a specific brand. As a result, the government purchased hundreds of thousands of IBM compatible desktop computers. This resulted in many brands disappearing off the market and the IBM compatible gaining enhancements and software to make it the most popular of all. From last to first.
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.
- 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.
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.
- 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.
- DVI (Digital Video Interface) - 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 have also released all-in-one computers such as Gateway. Some PC and refrigerator manufacturers have even included full featured PCs and monitors in refrigerators which could be considered all-in-one.