Types: A workstation is a high-end personal computer designed for technical, mathematical, 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. Workstations are used for tasks such as computer-aided design, drafting, and modeling, computation-intensive scientific and engineering calculations, image processing, architectural modeling, and computer graphics for animation and motion picture visual effects.

Desktop computer

Main article: Desktop computer

A Dell OptiPlex desktop computer

Before the widespread use of PCs, a computer that could fit on a desk was remarkably small, leading to the “desktop” nomenclature. More recently, the phrase usually indicates a particular style of the computer case. Desktop computers come in a variety of styles ranging from large vertical tower cases to small models that can be tucked behind or rest directly beneath (and support) LCD monitors.

While the term “desktop” often refers to a computer with a vertically aligned computer tower case, these varieties usually rest on the ground or underneath desks. Despite this seeming contradiction, the term “desktop” does typically refer to these vertical tower cases as well as the horizontally aligned models which are designed to literally rest on top of desks and are therefore more appropriate to the “desktop” term, although both types qualify for this “desktop” label in most practical situations aside from certain physical arrangement differences. Both styles of these computer cases hold the systems hardware components such as the motherboard, processor chip, other internal operating parts. Desktop computers have an external monitor with a display screen and an external keyboard, which are plugged into USB ports on the back of the computer case. Desktop computers are popular for home and business computing applications as they leave space on the desk for multiple monitors.

A gaming computer is a desktop computer that has a high-performance video card, processor and memory, to improve the speed and responsiveness of demanding video games.

An all-in-one computer (also known as single-unit PCs) is a desktop computer that combines the monitor and processor within a single unit. A separate keyboard and mouse are standard input devices, with some monitors including touchscreen capability. The processor and other working components are typically reduced in size relative to standard desktops, located behind the monitor, and configured similarly to laptops.

A nettops computer was introduced by Intel in February 2008, characterized by low cost and lean functionality. These were intended to be used with an Internet connection to run Web browsers and Internet applications.

An Antec Fusion V2 home theater PC, with a keyboard placed on top of it

A Home theater PC (HTPC) combines the functions of a personal computer and a digital video recorder. It is connected to a TV set or an appropriately sized computer display and is often used as a digital photo viewer, music and video player, TV receiver, and digital video recorder. HTPCs are also referred to as media center systems or media servers. The goal is to combine many or all components of a home theater setup into one box. HTPCs can also connect to services providing on-demand movies and TV shows. HTPCs can be purchased pre-configured with the required hardware and software needed to add television programming to the PC or can be assembled from components

Portable: The potential utility of portable computers was apparent early on. Alan Kay described the Dynabook in 1972, but no hardware was developed. The Xerox NoteTaker was produced in a very small experimental batch around 1978. In 1975, the IBM 5100 could be fit into a transport case, making it a portable computer, but it weighed about 50 pounds.

Before the introduction of the IBM PC, portable computers consisting of a processor, display, disk drives, and keyboard, in a suit-case style portable housing, allowed users to bring a computer home from the office or to take notes at a classroom. Examples include the Osborne 1 and Kaypro; and the Commodore SX-64. These machines were AC powered and included a small CRT display screen. The form factor was intended to allow these systems to be taken on board an airplane as carry-on baggage, though their high power demand meant that they could not be used in flight. The integrated CRT display made for a relatively heavy package, but these machines were more portable than their contemporary desktop equals. Some models had standard or optional connections to drive an external video monitor, allowing a larger screen or use with video projectors.

IBM PC-compatible suitcase format computers became available soon after the introduction of the PC, with the Compaq Portable being a leading example of the type. Later models included a hard drive to give the roughly equivalent performance to contemporary desktop computers.

The development of thin plasma display and LCD screens permitted a somewhat smaller form factor, called the “lunchbox” computer. The screen formed one side of the enclosure, with a detachable keyboard and one or two half-height floppy disk drives mounted facing the ends of the computer. Some variations included a battery, allowing operation away from AC outlets.

Notebook computers such as the TRS-80 Model 100 and Epson HX-20 had roughly the plan dimensions of a sheet of typing paper (ANSI A or ISO A4). These machines had a keyboard with slightly reduced dimensions compared to a desktop system, and a fixed LCD display screen coplanar with the keyboard. These displays were usually small, with 8 to 16 lines of text, sometimes only 40 columns line length. However, these machines could operate for extended times on disposable or rechargeable batteries. Although they did not usually include internal disk drives, this form factor often included a modem for telephone communication and often had provisions for an external cassette or disk storage. Later, clam-shell format laptop computers with similar small plan dimensions were also called “notebooks”.

Laptop:A laptop computer is designed for portability with a “clamshell” design, where the keyboard and computer components are on one panel, with a hinged second panel containing a flat display screen. Closing the laptop protects the screen and keyboard during transportation. Laptops generally have a rechargeable battery, enhancing their portability. To save power, weight, and space, laptop graphics cards are in many cases integrated into the CPU or chipset and use system RAM, resulting in reduced graphics performance when compared to a desktop machine. For this reason, desktop computers are usually preferred over laptops for gaming purposes.

Unlike desktop computers, only minor internal upgrades (such as memory and hard disk drive) are feasible owing to the limited space and power available. Laptops have the same input and output ports as desktops, for connecting to external displays, mice, cameras, storage devices, and keyboards. Laptops are also a little more expensive compared to desktops, as the miniaturized components for laptops themselves are expensive.

An Acer Aspire desktop replacement laptop

A desktop replacement computer is a portable computer that provides the full capabilities of a desktop computer. Such computers are currently large laptops. This class of computers usually includes more powerful components and a larger display than generally found in smaller portable computers, and may have limited battery capacity or no battery.

An HP netbook

Netbooks, also called mini notebooks or subnotebooks, were a subgroup of the laptop for general computing tasks and accessing web-based applications. Initially, the primary defining characteristic of netbooks was the lack of an optical disc drive, smaller size, and lower performance than full-size laptops. By mid-2009 netbooks had been offered to users “free of charge”, with an extended service contract purchase of a cellular data plan