Desktop Computer
A desktop computer is a personal computer (PC) 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. Today the phrase usually indicates a particular style of computer case. Desktop computers come in a variety of styles ranging from large vertical tower cases to small form factor 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. A specialized form of desktop case is used for home theatre systems, incorporating front-panel mounted controls for audio and video.
All-in-one All-in-one computers are desktop computers that combine the monitor into the same case as the CPU. Apple has manufactured several popular examples of all-in-one computers, such as the original Macintosh of the mid-1980s and the iMac of the late 1990s and 2000s. Some older 8-bit computers, such as the Commodore PET 2001 or Kaypro II, also fit into this category. All-in-one PCs are typically more portable than other desktop PCs and many have been built with carrying handles integrated into the case. They can simply be unplugged and transported to a new location.
However, like laptops, All-in-One desktop computers tend to suffer from a comparative lack of upgradeability or hardware customization, as internal hardware is often placed in the back of the visual display unit. Furthermore, in the case of the iMac line since 2002, the CPU and other internal hardware units are, more or less, permanently glued to the motherboard due to space constraints.
Desktop replacement computer
This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (July 2008) An Apple MacBook Pro 17" is often used as a desktop replacement.
A desktop replacement computer (dtr) is a personal computer that provides the full capabilities of a desktop computer while remaining portable. They are often larger, bulkier laptops. Because of their increased size, this class of computer usually includes more powerful components and a larger display than generally used in smaller portable computers and can have a relatively limited battery capacity (or none at all). Some use a limited range of desktop components to provide better performance at the expense of battery life. These are sometimes called desknotes, a portmanteau of the words "desktop" and "notebook," though the term is also applied to desktop replacement computers in general.
Origins The forerunners of the desktop replacement were the portable computers of the early-to-mid 1980s, such as the Osborne I,[2] the Compaq Portable[3] and the Commodore Executive 64 (SX-64) computers.[4] These computers contained the CPU, display, floppy disk drive and power supply all in a single briefcase-like enclosure. Similar in performance to the desktop computers of the era, they were easily transported and came with an attached keyboard that doubled as a protective cover when not in use. They could be used wherever space and an electrical outlet were available, as they had no battery.
The development of the laptop form factor gave new impetus to portable computer development. Many early laptops were feature-limited in the interest of portability, requiring such mobility-limiting accessories as external floppy drives or clip-on trackball pointing devices. The first laptop that could be used as an only computer was the PowerBook 500 series, with its built in ethernet, video, SCSI, ADB and serial ports, it duplicated the functionality of the desktop models.
The development of the modern desktop replacement computer came with the realization that many laptops were used in a semi-permanent location, often remaining connected to an external power source at all times. This suggested that a market existed for a laptop-style computer that would take advantage of the user's reduced need for portability, allowing for higher-performance components, greater expandability, and higher-quality displays. Desktop replacement computers are also often used with a docking station, to fully enjoy the desktop comfort.
Design features Modern desktop replacements generally perform better than traditional laptop-style computers as their size allows the inclusion of more powerful components. The larger body means more efficient heat-dissipation, allowing manufacturers to use components that would otherwise overheat during normal use. Furthermore, their increased size allows for greater expandability and features, as well as larger and brighter displays. However, these advantages generally come at a price premium, with many computers in this class costing as much as two desktop computers with similar specifications.
Using a laptop form factor, however, desktop replacements still often suffer from limitations similar to those of more mobile laptops. They usually lack the ability to accept standard PCI expansion cards, limiting their expandability somewhat. While the computers can offer slightly better cooling than other laptops, they rarely dissipate heat efficiently enough to allow for high-end desktop-class components, and thus may not reach the same performance levels as desktop computers.
Desktop replacement computers are, with a few exceptions, difficult to upgrade compared to desktop computers, with many of their major components (such as the display) integral to the design of the machine, and others (such as the CPU and GPU) often being hard to access and replace.[5] A small segment of desktop replacements do not include a battery as a standard feature, while some do not include PC-Card support. They have the same limitations on serviceability as laptops, and can rarely use identical components to a desktop computer.
