In personal computing, a tower unit, or simply a tower, is a form factor of desktop computer case whose height is much greater than its width, thus having the appearance of an upstanding tower block, as opposed to a traditional "pizza box" computer case whose width is greater than its height and appears lying flat.
Compared to a pizza box case, the tower tends to be larger and offers more potential for internal volume for the same desk area occupied, and therefore allows more hardware installation and theoretically better airflow for cooling. Multiple size subclasses of the tower form factor have been established to differentiate their varying sizes, including full-tower, mid-tower, midi-tower, mini-tower, and deskside; these classifications are however nebulously defined and inconsistently applied by different manufacturers.
Although the traditional layout for a tower system is to have the case placed on top of the desk alongside the monitor and other peripherals, a far more common configuration is to place the case on the floor below the desk or in an under-desk compartment, in order to free up desktop space for other items. [1] Computer systems housed in the horizontal "pizza box" form factor—once popularized by the IBM PC in the 1980s but fallen out of mass use since the late 1990s—have been given the term desktops to contrast them with the often underdesk-situated towers.
Tower cases are often categorized as mini-tower, midi-tower, mid-tower, full-tower, and deskside. The terms are subjective and inconsistently defined by different manufacturers. [2] [3] [4]
Full-tower cases, typically 20 inches (51 cm) or more in height, are designed for maximum scalability. [5] For case modding enthusiasts and gamers wanting to play the most technically challenging video games, the full-tower case also makes for an ideal gaming PC case because of their ability to accommodate extensive water cooling setups and larger case fans. [6] Traditionally, full-tower systems had between four and six externally accessible half-height 5.25-inch drive bays and up to ten 3.5-inch drive bays. [6] [5] : 138 Some full-tower cases included locking side-doors and other physical security features to prevent theft of the discs inside those bays. [7] However, as modern computing technology has moved away from mechanical hard drives and optical drives toward solid-state devices such as USB flash drives, solid-state drives (SSDs), large-capacity external storage, and cloud storage, such an abundance of internal and external drive bays is less common. [8] [9] More recent full-tower cases instead only have one or two external drive bays, or none at all, with the internal bays moved elsewhere in the case to free up room and improve airflow. [10]
Full-tower cases readily fit full-size ATX motherboards but may also accommodate smaller microATX motherboards due to the former standard's interoperability in mounting holes. Full-tower cases may also have increased dimensional depth and length over their shorter counterparts, allowing them to accommodate Extended ATX motherboards, larger graphics cards and heat sinks. [10] Since the 2010s, full-tower cases are commonly used by enthusiasts as showpiece cases with custom water cooling, RGB LED lighting, and tempered glass or acrylics side panel. [11] [12] [13] They may also hold two motherboards (as is the case with the Corsair 1000D) and dual power supplies (Corsair 900D). [14] [15]
Mid-tower cases, usually between 16 inches (41 cm) and 20 inches (51 cm) in height, are the most common form factor of personal computer towers. [6] [10] [16] Before the late 2010s, mid-towers contained between three and four 5.25-inch drive bays and an equivalent number of 3.5-inch bays to house optical disc drives, floppy disk drives and hard disk drives, leaving just enough room for a standard ATX motherboard and power supply unit. [16] Since the widespread adoption of USB flash drives, solid-state drives (which take up far less space than spinning hard disk drives) and the declining usage of internal optical drives, the number of drive bays has become less of a concern to the contemporary computer user, the internal space of mid-towers is now used more commonly for closed-loop water coolers, dual graphics cards, and tightly stacked SSDs. [10]
The marketing term midi-tower sometimes refers to cases smaller than a mid-tower but still larger than a mini-tower (see below), typically with two to three external bays. [17] Other times the term may be synonymous with mid-tower. [18]
Mini-tower cases, between 12 inches (30 cm) and 16 inches (41 cm) in height, [19] slot between the Mini-ITX specification for small-form-factor PCs and the archetypal mid-tower. Mini-towers typically will only accommodate microATX motherboards and for this reason sell in fewer numbers in the consumer market than the other size classes of computer towers. [10] [20] : 94–95 Traditionally, mini-towers had only one or two disk drive bays (either 5.25-inch or 3.5-inch). [21]
The term deskside is primarily a term of art in the workstation market, referring to computer towers with a much wider footprint than traditional domestic tower units. These wider deskside cases accommodate a far greater amount of central processing units (CPUs), drive bays, memory slots, expansion slots, peripherals, and I/O adapters, among other devices. [4] [22] : 20 [23] : 57
The tower form factor may be seen as a proportional miniaturization of mainframe computers and minicomputers, some of which comprise massive tall enclosures standing almost to the ceiling. [24] In the advent of the microcomputer era, most systems were configured with the keyboard built into the same chassis that the main system circuit board resides. Such computers were also termed home computers and counted such popular systems as the Apple II, TRS-80, VIC-20, and Commodore 64, among others. In 1981, IBM introduced the IBM Personal Computer, a system which was met widespread adoption in both enterprises and home businesses within a couple years and set a new de facto standard for the physical configuration of microcomputers. The IBM PC and successors housed the system board and expansion cards in a separate horizontal unit, with the keyboard usually in front and the prescribed CRT monitor resting on top of the system unit; the front of the system unit houses one or more disk drives. [25]
In 1982, NCR introduced the Tower series of workstation computers, named so for their tall, upright configuration, intended to be stowed away under a desk. The first, the Tower 1632, is 29 inches tall and featured a Motorola 68000 microprocessor. Costing upwards of $12,500, the 1632 is meant to run Unix and supports up to 16 simultaneous networked users. [26] NCR continued adding to the Tower line into the late 1980s. [27] [28] [29]
In 1983, Tandy Corporation offered their Tandy 2000 with an optional floor stand, turning the normally horizontal desktop case on its side and allowing it to be stashed under-desk; the square badge on the Tandy 2000 can be removed and rotated upright in turn. [30] IBM followed suit with their PC/AT in 1984, which included an optional "floor-standing enclosure" for $165. [31] Of the three initial entrants in the company's RT PC line in 1986, two were tower units, while the other was a traditional horizontal case like the AT and the PCs before it. [32]
In 1987, IBM introduced the PS/2 Model 60, an initial entry in the company's Personal System/2 line of personal computers. It was IBM's first Intel-based PC built entirely into a tower case. [33] The PS/2 Model 60 was comparable in technical specification to its sibling the PS/2 Model 50, which sported a horizontal desktop form factor. Whereas the Model 50 had only four expansion slots and three drive bays, however, the Model 60 featured eight expansion slots and four drive bays. Because of the latter's increased potential for connectivity and multitasking, technology journalists envisioned the PS/2 Model 60 as a multiuser machine, although multiuser operating systems supporting the 80286 processor of both the Models 50 and 60 were hard to come by in 1987. [34] IBM followed up with the tower-based PS/2 Model 80 later that year, their first PC powered by an i386 processor. [35]
According to The New York Times in 1988, the PS/2 Models 60 and 80 started the trend of computer manufacturers offering IBM PC compatibles in optional tower form factors:
A countertrend is to take PCs off the desk and put them on the floor. IBM started it with the tower configuration for its PS/2 Models 60 and 80, and at least a dozen companies were showing floor-standing PCs at Comdex. Freed from the need to fit on a desk, some of the tower models are actually getting bigger to accommodate large disk drives, a variety of floppy drives and backup devices, and room for up to a dozen slots for plug-in boards. [36]
Aftermarket floor stands, allowing existing horizontal desktop computers to be stored upright on the floor, were sold in the late 1980s by companies such as Curtis Computer Products. [37] Recommending such kits in The Washington Post in 1989, Brit Hume called the tower the best configuration for ergonomics and noted that, "Contrary to popular myth, standing vertically will not hurt the computer or throw off your disk drives." [37]
The transition in dominance from horizontal desktop computers to towers was mostly complete by 1994, according to a period article in PC Week . [38] Computer cases or pre-built systems offered in the traditional horizontal form factor have since been separately categorized as desktops, to contrast them with the usually-floor-situated towers. [21]
Brian Benchoff of Hackaday argued that the popularity of the Macintosh Quadra 700 was the turning point for computer manufacturers to move over to the tower form factor en masse. The tower form factor of the Quadra 700 was by necessity: common peripherals of the Quadra were the relatively extremely heavy color CRT monitors offered by Apple (those whose screens measured 20 inches and over diagonally could weigh 80 lbs or more) favored by the desktop publishing industry during the 1990s. Such monitors threatened to crush the plastic frames of the Macintosh IIcx and Macintosh IIci; customers might have been tempted to fit such heavy monitors atop the IIcx and IIci because of their horizontal form factor. [25]
A motherboard is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems, such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general use.
The Tandy 1000 was the first in a series of IBM PC compatible home computers produced by the Tandy Corporation, sold through its Radio Shack and Radio Shack Computer Center stores. Introduced in 1984, the Tandy 1000 line was designed to offer affordable yet capable systems for home computing and education. Tandy-specific features, such as enhanced graphics, sound, and a built-in joystick port, made the computers particularly attractive for home use.
A desktop computer is a personal computer designed for regular use at a stationary location on or near a desk due to its size and power requirements. The most common configuration has a case that houses the power supply, motherboard, disk storage ; a keyboard and mouse for input; and a monitor, speakers, and, often, a printer for output. The case may be oriented horizontally or vertically and placed either underneath, beside, or on top of a desk.
The IBM Personal Computer AT was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 80286 microprocessor.
ATX is a motherboard and power supply configuration specification, patented by David Dent in 1995 at Intel, to improve on previous de facto standards like the AT design. It was the first major change in desktop computer enclosure, motherboard and power supply design in many years, improving standardization and interchangeability of parts. The specification defines the dimensions; the mounting points; the I/O panel; and the power and connector interfaces among a computer case, a motherboard, and a power supply.
In the era of IBM compatible personal computers, the AT form factor comprises the dimensions and layout of the motherboard for the IBM AT. Baby AT motherboards are slightly smaller, measuring 8.5" by 13". Like the IBM PC and IBM XT models before it, many third-party manufacturers produced motherboards compatible with the IBM AT form factor, allowing end users to upgrade their computers for faster processors. The IBM AT became a widely copied design in the booming home computer market of the 1980s. IBM clones made at the time began using AT compatible designs, contributing to its popularity. In the 1990s many computers still used AT and its variants. Since 1997, the AT form factor has been largely supplanted by ATX.
A computer case, also known as a computer chassis, is the enclosure that contains most of the hardware of a personal computer. The components housed inside the case are referred as the internal hardware, while hardware outside the case are known as peripherals.
LPX, originally developed by Western Digital, was a loosely defined motherboard format widely used from 1987 to the late 1990s.
Small form factor is a term used for desktop computers and for some of their components, chassis and motherboard, to indicate that they are designed in accordance with one of several standardized form factors intended to minimize the volume and footprint of a desktop computer compared to the standard ATX form factor.
A power supply unit (PSU) converts mains AC to low-voltage regulated DC power for the internal components of a desktop computer. Modern personal computers universally use switched-mode power supplies. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the main voltage
The PS/ValuePoint personal computer was IBM's answer to the PC clone market, where the IBM PS/2 could not compete due to price and proprietary interfaces. Announced in October 1992 and withdrawn in July 1995, it was replaced by the IBM PC Series 300.
The Personal Computer Series, or PC Series, was IBM's follow-up to the Personal System/2 and PS/ValuePoint. Announced in October 1994 and withdrawn in October 2000, it was replaced by the IBM NetVista, apart from the Pentium Pro-based PC360 and PC365, which were replaced by the IBM IntelliStation.
In computing, the motherboard form factor is the specification of a motherboard – the dimensions, power supply type, location of mounting holes, number of ports on the back panel, etc. Specifically, in the IBM PC compatible industry, standard form factors ensure that parts are interchangeable across competing vendors and generations of technology, while in enterprise computing, form factors ensure that server modules fit into existing rackmount systems. Traditionally, the most significant specification is for that of the motherboard, which generally dictates the overall size of the case. Small form factors have been developed and implemented.
The PS/1 is a brand for a line of personal computers that marked IBM's return to the home market in 1990, five years after the IBM PCjr. It was replaced by the IBM Aptiva in September 1994.
The Personal System/2 Model 30 and Personal System/2 Model 30 286 are IBM's entry-level desktop computers in their Personal System/2 (PS/2) family of personal computers. As opposed to higher-end entries in the PS/2 line which use Micro Channel bus architecture, the Model 30 features an Industry Standard Architecture bus, allowing it to use expansion cards from its direct predecessors, the PC/XT and the PC/AT. The original PS/2 Model 30, released in April 1987, is built upon the Intel 8086 microprocessor clocked at 8 MHz and features the 8-bit ISA bus; the Model 30 286, released in September 1988, features the Intel 80286 clocked at 10 MHz and includes the 16-bit ISA bus.
The Personal System/2 Model 50 is a midrange desktop computer in IBM's Personal System/2 (PS/2) family of personal computers. First released in April 1987, the Model 50 features an Intel 80286 processor running at a clock speed of 10 MHz. In June 1988, the PS/2 Model 50 received an update in the form of the Personal System/2 Model 50 Z, which offered faster RAM, eliminating the insertion of wait states endemic to the original Model 50 and increasing system performance. The Model 50 was the best-selling line of PS/2 for several years, IBM selling over 440,000 units in the first year of its availability.
The Personal System/2 Model 55 SX is a midrange desktop computer in IBM's Personal System/2 (PS/2) family of personal computers. First released in May 1989, the Model 55 SX features an Intel 386SX processor running at a clock speed of 16 MHz. In October 1990, IBM introduced a diskless workstation version of the Model 55 SX, called the Personal System/2 Model 55 LS. The Model 55 SX was the best-ever selling computer in the PS/2 range, accounting for 23 percent of IBM's PC sales within four months of its introduction. By 1991, the PS/2 Model 55 SX was the best-selling x86-based PC in the world.
The Personal System/2 Model 60 is a high-end desktop computer in IBM's Personal System/2 (PS/2) family of personal computers. First released in April 1987, the Model 60 features an Intel 80286 processor running at a clock speed of 10 MHz, the same as its midrange counterpart, the Personal System/2 Model 50. Unlike the Model 50, the Model 60 was built into a tower case and featured four more 16-bit MCA expansion slots and an additional drive bay. The Model 60 was IBM's first Intel-based PC built into a tower form factor and was influential in popularizing towers in computer case design.
The Personal System/2 Model 70 386 and Personal System/2 Model 70 486 are midrange desktop computers in IBM's Personal System/2 (PS/2) family of personal computers. The PS/2 Model 70 386, released in April 1987, features an Intel 386 microprocessor clocked between 16 MHz and 25 MHz and features the 32-bit Micro Channel architecture (MCA) bus; the Model 70 486, released in December 1989, features the Intel 486 clocked at 25 MHz and also includes the 32-bit MCA bus. The latter is essentially a Model 70 386 with the 486/25 Power Platform pre-installed; this was a CPU upgrade card for the Model 70 386 released earlier in October 1989 that was the first commercially available product to use the 486 processor. Both editions of Model 70 are housed in the same case as the earlier PS/2 Model 50 from 1987.
The Personal System/2 Model 80 is a high-end desktop computer in IBM's Personal System/2 (PS/2) family of personal computers. First released in July 1987, the Model 80 features the 32-bit Intel 386 processor running at a clock speed of 16 MHz. The Model 80 was built into a tower case, the same one as its 16-bit counterpart the PS/2 Model 60. It sports several 32-bit MCA expansion slots—the only PS/2 model to sport such slots at the time of its release—and between five to six drive bays. The PS/2 Model 80 was the highest-end PS/2 in the original 1987 line-up and was IBM's first PC based on the 386 processor. The Model 80 received several updates over the course of its lifespan, increasing the computer's hard drive capacity as well as the clock speed of its processor and the maximum supported RAM. IBM discontinued the Model 80 in 1992.