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65-493: Over the years since the introduction of the IBM PC , it and its compatibles have had many form factors of drive bays. Four form factors are in common use today, the 5.25-inch, 3.5-inch, 2.5-inch or 1.8-inch drive bays. These names do not refer to the width of the bay itself, but rather to the width of the disks used by the drives mounted in these bays. 8.0-inch drive bays were found in early IBM computers, CP/M computers, and

130-629: A 1.8-inch drive are specified in the SFF standard specifications SFF-8111 and SFF-8120 , which were incorporated into the EIA-720 specification by the Electronic Industries Association (EIA). Drive bays are most commonly used to store disk drives , although they can also be used for front-end USB ports, I/O bays, card readers , fans , fan controllers, RAID controllers, tool storage, and other uses. Some computers have

195-418: A storage medium . Handwriting , phonographic recording, magnetic tape , and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are considered by some as data storage. Recording may be accomplished with virtually any form of energy . Electronic data storage requires electrical power to store and retrieve data. Data storage in a digital, machine-readable medium

260-468: A computer through retail channels rather than directly to customers. Because IBM did not have retail experience, they partnered with the retail chains ComputerLand and Sears , who provided important knowledge of the marketplace and became the main outlets for the PC. More than 190 ComputerLand stores already existed, while Sears was in the process of creating a handful of in-store computer centers for sale of

325-442: A dedicated power supply and included a hard drive. Although official hard drive support did not exist, the third party market did provide early hard drives that connected to the floppy disk controller , but required a patched version of PC DOS to support the larger disk sizes. The only option for human interface provided in the base PC was the built-in keyboard port, meant to connect to the included Model F keyboard. The Model F

390-405: A floppy drive at all, and may lack any externally accessible 3.5″ bays. There are adapters, sometimes called a "sled", which can be used to mount a 3.5″ device in a 5.25″ bay. More recently, it is becoming common to use 3.5″ bays for smart card and memory card readers, or for panels with additional USB ports. A 3.5″ drive containing both a card reader and a floppy drive, as well as a USB port,

455-583: A hard drive, the motherboard did not support BIOS expansion ROMs which was needed to support a hard drive controller, and both PC DOS and the BIOS had no support for hard disks. After the XT was released, IBM altered the design of the 5150 to add most of these capabilities, except for the upgraded power supply. At this point adding a hard drive was possible, but required the purchase of the IBM 5161 Expansion Unit, which contained

520-567: A library of common functions that all software can use for many purposes, such as video output, keyboard input, disk access, interrupt handling, testing memory, and other functions. IBM shipped three versions of the BIOS throughout the PC's lifespan. While most home computers had built-in video output hardware, IBM took the unusual approach of offering two different graphics options, the MDA and CGA cards. The former provided high-resolution monochrome text, but could not display anything except text, while

585-401: A maximum of 64 KB onboard, and the more common 64 KB revision to a maximum of 256 KB on the motherboard. RAM cards could upgrade either variant further, for a total of 640 KB conventional memory , and possibly several megabytes of expanded memory beyond that, though on PC/XT-class machines, the latter was a very expensive third-party hardware option only available later in

650-657: A mouse.) Connectivity to other computers and peripherals was initially provided through serial and parallel ports. IBM provided a serial card based on an 8250 UART . The BIOS supports up to two serial ports. IBM provided two different options for connecting Centronics-compatible parallel printers. One was the IBM Printer Adapter, and the other was integrated into the MDA as the IBM Monochrome Display and Printer Adapter. The expansion capability of

715-467: A personal computer, possibly a miniaturized version of the IBM System/370 , and Matsushita acknowledged publicly that it had discussed with IBM the possibility of manufacturing a personal computer in partnership, although this project was abandoned. The public responded to these rumors with skepticism, owing to IBM's tendency towards slow-moving, bureaucratic business practices tailored towards

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780-505: A policy of strict secrecy, with all other IBM divisions kept in the dark about the project. Several CPUs were considered, including the Texas Instruments TMS9900 , Motorola 68000 and Intel 8088 . The 68000 was considered the best choice, but was not production-ready like the others. The IBM 801 RISC processor was also considered, since it was considerably more powerful than the other options, but rejected due to

845-657: A rapidly changing market. The idea of acquiring Atari was considered but rejected in favor of a proposal by Lowe that by forming an independent internal working group and abandoning all traditional IBM methods, a design could be delivered within a year and a prototype within 30 days. The prototype worked poorly but was presented with a detailed business plan which proposed that the new computer have an open architecture , use non-proprietary components and software, and be sold through retail stores, all contrary to IBM practice. It also estimated sales of 220,000 computers over three years, more than IBM's entire installed base . This swayed

910-595: A separate monochrome monitor for text menus. Third parties went on to provide an enormous variety of aftermarket graphics adapters, such as the Hercules Graphics Card . The software and hardware of the PC, at release, was designed around a single 8-bit adaptation of the ASCII character set, now known as code page 437 . The two bays in the front of the machine could be populated with one or two 5.25″ floppy disk drives, storing 160 KB per disk side for

975-621: A small system monitor LCD mounted in a drive bay. When installing a drive in a bay, it is usually secured with four screws that hold the drive in the bay, although toolless fasteners are becoming more common. Then, any necessary power, data transfer, and other cables are routed into and connected to the rear of the drive. The drive bay is usually just big enough for the drive to fit inside. Since computers have 12 V rails on their motherboards, some computer hobbyist websites even sell addons for cigarette lighter receptacles to power or recharge devices made to draw power from automobiles, though USB

1040-520: A substantial influence on the personal computer market ; the specifications of the IBM PC became one of the most popular computer design standards in the world. The only significant competition it faced from a non-compatible platform throughout the 1980s was from Apple 's Macintosh product line, as well as consumer-grade platforms created by companies like Commodore and Atari . Most present-day personal computers share architectural features in common with

1105-459: A total of 320 KB of storage on one disk. The floppy drives require a controller card inserted in an expansion slot, and connect with a single ribbon cable with two edge connectors. The IBM floppy controller card provides an external 37-pin D-sub connector for attachment of an external disk drive, although IBM did not offer one for purchase until 1986. As was common for home computers of the era,

1170-403: A year. By 1984, IBM's revenue from the PC market was $ 4 billion, more than twice that of Apple. A 1983 study of corporate customers found that two thirds of large customers standardizing on one computer chose the PC, while only 9% chose Apple. A 1985 Fortune survey found that 56% of American companies with personal computers used PCs while 16% used Apple. Almost as soon as the PC reached

1235-407: Is already available for charging devices like cell phones and portable media players . Drive bay-compatible computer case accessories that do not connect to the motherboard or power supply at all are also common, such as small storage drawers or even cup holders . IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC ) is the first microcomputer released in

1300-556: Is also available. The dimensions of a 3.5″ drive are specified in the SFF standard specifications SFF-8300 and SFF-8301 , which were incorporated into the EIA-740 specification by the Electronic Industries Association (EIA). For 2.5-inch bays, actual dimensions are 2 + 3 ⁄ 4 inches (69.9 mm) wide, between 5 millimetres (0.20 in) and 3 ⁄ 4 inch (19.1 mm) high, and 3.955 inches (100.5 mm) deep. However, most laptops have drive bays smaller than

1365-468: Is distributed and can be stored in four storage media–print, film, magnetic, and optical–and seen or heard in four information flows–telephone, radio and TV, and the Internet as well as being observed directly. Digital information is stored on electronic media in many different recording formats . With electronic media , the data and the recording media are sometimes referred to as "software" despite

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1430-411: Is housed in a wide, short steel chassis intended to support the weight of a CRT monitor. The front panel is made of plastic, with an opening where one or two disk drives can be installed. The back panel houses a power inlet and switch, a keyboard connector, a cassette connector and a series of tall vertical slots with blank metal panels which can be removed in order to install expansion cards. Internally,

1495-411: Is sometimes called digital data . Computer data storage is one of the core functions of a general-purpose computer . Electronic documents can be stored in much less space than paper documents . Barcodes and magnetic ink character recognition (MICR) are two ways of recording machine-readable data on paper. A recording medium is a physical material that holds information. Newly created information

1560-412: Is stored on digital storage devices than on analog storage devices. In 1986, approximately 1% of the world's capacity to store information was in digital format; this grew to 3% by 1993, to 25% by 2000, and to 97% by 2007. These figures correspond to less than three compressed exabytes in 1986, and 295 compressed exabytes in 2007. The quantity of digital storage doubled roughly every three years. It

1625-573: The IBM PC model line and the basis for the IBM PC compatible de facto standard . Released on August 12, 1981, it was created by a team of engineers and designers at International Business Machines (IBM), directed by William C. Lowe and Philip Don Estridge in Boca Raton, Florida . Powered by an x86 -architecture Intel 8088 processor, the machine was based on open architecture and third-party peripherals. Over time, expansion cards and software technology increased to support it. The PC had

1690-640: The IBM System/23 Datamaster . The 62-pin expansion bus slots were also designed to be similar to the Datamaster slots, and its keyboard design and layout became the Model F keyboard shipped with the PC, but otherwise the PC design differed in many ways. The 8088 motherboard was designed in 40 days, with a working prototype created in four months, demonstrated in January 1981. The design

1755-512: The TRS-80 Model II . They were 4 + 5 ⁄ 8 inches (117.5 mm) high, 9 + 1 ⁄ 2 inches (241.3 mm) wide, and approximately 14 + 1 ⁄ 4 inches (361.9 mm) deep, and were used for hard disk drives and floppy disk drives. This form factor is obsolete. 5.25-inch drive bays are divided into two height specifications, full-height and half-height . Full-height bays were found in old PCs in

1820-496: The 15 mm specification. 2.5-inch hard drives may range from 7 mm to 15 mm in height. There are two heights that appear to be prominent. 9.51 mm size drives are predominantly used by laptop manufacturers. 2.5-inch Velociraptor and some higher capacity drives (above 1 TB), are 15 mm in height. The greater height of the 15 mm drives allows more platters and therefore greater data capacities. Many laptop drive bays are designed to be removable trays in which

1885-506: The 5100 had a price tag as high as $ 20,000. Their entry into the home computer market needed to be competitively priced. In 1980, IBM president John Opel, recognizing the value of entering this growing market, assigned William C. Lowe and Philip Don Estridge as heads of the new Entry Level Systems unit in Boca Raton, Florida. Market research found that computer dealers were very interested in selling an IBM product, but they insisted

1950-443: The 60 mm × 70 mm are 2.75 in wide by 0.276–0.374 in high and 2.362 in deep (69.85 mm × 7–9.5 mm × 60 mm). The actual dimensions of the 54 mm × 78 mm are 2.126 in wide by 0.197 or 0.315 in high and 3.091 in deep (54 mm × 5 or 8 mm × 78.5 mm). These drives have been used in small devices, including as add-ons to game systems. The dimensions of

2015-509: The CPU's I/O lines. IBM referred to these as "I/O slots", but after the expansion of the PC clone industry they became retroactively known as the ISA bus . At the back of the machine is a metal panel, integrated into the steel chassis of the system unit, with a series of vertical slots lined up with each card slot. Disk drives Data storage is the recording (storing) of information ( data ) in

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2080-491: The Corporate Management Committee, which converted the group into a business unit named "Project Chess", and provided the necessary funding and authority to do whatever was needed to develop the computer in the given timeframe. The team received permission to expand to 150 people by the end of 1980, and in one day more than 500 IBM employees called in asking to join. The design process was kept under

2145-510: The IBM 5150's lifecycle and only usable with dedicated software support (i.e. only accessible via a RAM window in the Upper Memory Area ); this was relatively rarely equipped and utilized on the original IBM PC, much less fully so, thus the machine's maximum RAM configuration as commonly understood was 640 KB. The BIOS is the firmware of the IBM PC, occupying one 8 KB chip on the motherboard. It provides bootstrap code and

2210-435: The IBM PC offered a port for connecting a cassette data recorder . Unlike the typical home computer however, this was never a major avenue for software distribution, probably because very few PCs were sold without floppy drives. The port was removed on the very next PC model, the XT. At release, IBM did not offer any hard disk drive option and adding one was difficult - the PC's stock power supply had inadequate power to run

2275-399: The IBM PC was very significant to its success in the market. Some publications highlighted IBM's uncharacteristic decision to publish complete, thorough specifications of the system bus and memory map immediately on release, with the intention of fostering a market of compatible third-party hardware and software. The motherboard includes five 62-pin card edge connectors which are connected to

2340-462: The PC, covering such features as the bytecoding for color monitors, DMA access operation, and the keyboard interface. They were never enforced. Many of the designers were computer hobbyists who owned their own computers, including many Apple II owners, which influenced the decisions to design the computer with an open architecture and publish technical information so others could create compatible software and expansion slot peripherals. During

2405-470: The body is standardized, but also size of the bezel). 3.5-inch bays, like their larger counterparts, are named after diskette dimensions; their actual dimensions are 4 inches (101.6 mm) wide by 1.028 inches (26.1 mm) high. Those with an opening in the front of the case are generally used for floppy or Zip drives. Hard drives in modern computers are typically mounted in fully internal 4″ (nominally 3.5″) bays. Most modern computers do not come with

2470-520: The chassis is dominated by a motherboard which houses the CPU, built-in RAM, expansion RAM sockets, and slots for expansion cards. The IBM PC was highly expandable and upgradeable, but the base factory configuration included: The PC is built around a single large circuit board called a motherboard which carries the processor, built-in RAM, expansion slots, keyboard and cassette ports, and the various peripheral integrated circuits that connected and controlled

2535-467: The company use a design based on standard parts, not IBM-designed ones so that stores could perform their own repairs rather than requiring customers to send machines back to IBM for service. Another source cites time pressure as the reason for the decision to use third-party components. Atari proposed to IBM in 1980 that it act as original equipment manufacturer for an IBM microcomputer, a potential solution to IBM's known inability to move quickly to meet

2600-618: The components of the machine. The peripheral chips included an Intel 8259 PIC , an Intel 8237 DMA controller, and an Intel 8253 PIT . The PIT provides 18.2 Hz clock "ticks" and dynamic memory refresh timing. The CPU is an Intel 8088 , a cost-reduced form of the Intel 8086 which largely retains the 8086's internal 16-bit logic, but exposes only an 8-bit bus. The CPU is clocked at 4.77 MHz, which would eventually become an issue when clones and later PC models offered higher CPU speeds that broke compatibility with software developed for

2665-469: The design constraint to use off-the-shelf parts . The TMS9900 was rejected as it was inferior to the Intel 8088. IBM chose the 8088 over the similar but superior 8086 because Intel offered a better price for the former and could provide more units, and the 8088's 8-bit bus reduced the cost of the rest of the computer. The 8088 had the advantage that IBM already had familiarity with the 8085 from designing

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2730-534: The design process IBM avoided vertical integration as much as possible, for example choosing to license Microsoft BASIC rather than utilizing the in-house version of BASIC used for mainframes due to the better existing public familiarity with the Microsoft version. The IBM PC debuted on August 12, 1981, after a twelve-month development. Pricing started at $ 1,565 for a configuration with 16 KB RAM, Color Graphics Adapter , keyboard, and no disk drives. The price

2795-424: The drives are mounted, to ease removal and replacement. The dimensions of a 2.5-inch drive are specified in the SFF standard specifications SFF-8200 and SFF-8201 , which were incorporated into the EIA-720 specification by the Electronic Industries Association (EIA). 1.8-inch bays have two specifications, a 60 mm × 70 mm form factor, and a 54 mm × 78 mm form factor. The actual dimensions of

2860-408: The early to mid-1980s. They were 3 + 1 ⁄ 4 inches (82.6 mm) high, 5 + 3 ⁄ 4 inches (146.1 mm) wide, and up to 8 inches (203.2 mm) deep, used mainly for hard disk drives and floppy disk drives. This is the size of the internal (screwed) part of the bay, as the front side is actually 5 + 7 ⁄ 8 inches (149.2 mm). The difference between those widths and

2925-428: The environment or to purposely make data expire over time. Data such as smoke signals or skywriting are temporary by nature. Depending on the volatility, a gas (e.g. atmosphere , smoke ) or a liquid surface such as a lake would be considered a temporary recording medium if at all. A 2003 UC Berkeley report estimated that about five exabytes of new information were produced in 2002 and that 92% of this data

2990-450: The keyboard was extremely positive, with some sources describing it as a major selling point of the PC and even as "the best keyboard available on any microcomputer." At release, IBM provided a Game Control Adapter which offered a 15-pin port intended for the connection of up to two joysticks, each having two analog axes and two buttons. (The early PCs predated the advent of the " Windows, Icons, Mouse, Pointer" concept and so did not have

3055-411: The latter provided medium- and low-resolution color graphics and text. CGA used the same scan rate as NTSC television , allowing it to provide a composite video output which could be used with any compatible television or composite monitor , as well as a direct-drive TTL output suitable for use with any RGBI monitor using an NTSC scan rate. IBM also sold the 5153 color monitor for this purpose, but it

3120-554: The market, rumors of clones began, and the first legal PC-compatible clone—the MPC 1600 by Columbia Data Products —was released in June 1982, less than a year after the PC's debut. Eventually, IBM sold its PC business to Lenovo in 2004 . For low cost and a quick design turnaround time, the hardware design of the IBM PC used entirely "off-the-shelf" parts from third party manufacturers, rather than unique hardware designed by IBM. The PC

3185-515: The market, sold only 69,000. Software support from the industry grew rapidly, with the IBM nearly instantly becoming the primary target for most microcomputer software development. One publication counted 753 software packages available a year after the PC's release, four times as many as were available for the Macintosh a year after its launch. Hardware support also grew rapidly, with 30–40 companies competing to sell memory expansion cards within

3250-407: The more common use of the word to describe computer software . With ( traditional art ) static media, art materials such as crayons may be considered both equipment and medium as the wax, charcoal or chalk material from the equipment becomes part of the surface of the medium. Some recording media may be temporary either by design or by nature. Volatile organic compounds may be used to preserve

3315-567: The most obvious use was the addition of an Intel 8087 math coprocessor, which improved floating-point math performance. PC mainboards were manufactured with the first memory bank of initially Mostek 4116-compatible, or later 4164-compatible DIP DRAMs soldered to the board, for a minimum configuration of first just 16 KB, or later 64 KB of RAM. Memory upgrades were provided by IBM and third parties both for socketed installation in three further onboard banks, and as ISA expansion cards. The early 16 KB mainboards could be upgraded to

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3380-555: The name indicates, two half-height devices can fit in one full-height bay. The dimensions of a 5.25-inch floppy drive are specified in the SFF standard specifications which were incorporated into the EIA-741 "Specification for Small Form Factor 133.35 mm (5.25 in) Disk Drives" by the Electronic Industries Association ( EIA ). Dimensions of 5.25 optical drives are specified in the SFF standard (they are somewhat shorter and not only size of

3445-551: The name of the bay size is because it is named after the size of floppy that would fit in those drives, a 5.25-inch-wide square. Half-height drive bays are 1 + 5 ⁄ 8 inches (41.3 mm) high by 5 + 3 ⁄ 4 inches (146.1 mm) wide, and are the standard housing for CD and DVD drives in modern computers. They were sometimes used for other things in the past, including hard disk drives (roughly between 10 and 100 MB) and floppy disk drives. Often represented as 5.25-inch, these floppy disk drives are obsolete. As

3510-415: The new product. Reception was overwhelmingly positive, with analysts estimating sales volume in the billions of dollars in the first few years after release. After release, IBM's PC immediately became the talk of the entire computing industry. Dealers were overwhelmed with orders, including customers offering pre-payment for machines with no guaranteed delivery date. By the time the machine began shipping,

3575-430: The original IBM PC, including the Intel -based Mac computers manufactured from 2006 to 2022 . Prior to the 1980s, IBM had largely been known as a provider of business computer systems. As the 1980s opened, their market share in the growing minicomputer market failed to keep up with competitors, while other manufacturers were beginning to see impressive profits in the microcomputer space. The market for personal computers

3640-503: The original PC. The single base clock frequency for the system was 14.31818 MHz, which when divided by 3, yielded the 4.77 MHz for the CPU (which was considered close enough to the then 5 MHz limit of the 8088), and when divided by 4, yielded the required 3.579545 MHz for the NTSC color carrier frequency. The PC motherboard included a second, empty socket, described by IBM simply as an "auxiliary processor socket", although

3705-449: The production of large, sophisticated and expensive business systems. As with other large computer companies, its new products typically required about four to five years for development, and a well publicized quote from an industry analyst was, "IBM bringing out a personal computer would be like teaching an elephant to tap dance." IBM had previously produced microcomputers, such as 1975's IBM 5100 , but targeted them towards businesses;

3770-407: The term "PC" was becoming a household name. Sales exceeded IBM's expectations by as much as 800% (9x), with the company at one point shipping as many as 40,000 PCs per month. IBM estimated that home users made up 50 to 70% of purchases from retail stores. In 1983, IBM sold more than 750,000 machines, while Digital Equipment Corporation , one of the companies whose success had spurred IBM to enter

3835-402: Was designed to compete with comparable machines in the market. For comparison, the Datamaster, announced two weeks earlier as IBM's least expensive computer, cost $ 10,000. IBM's marketing campaign licensed the likeness of Charlie Chaplin 's character " The Little Tramp " for a series of advertisements based on Chaplin's movies, played by Billy Scudder. The PC was IBM's first attempt to sell

3900-538: Was dominated at the time by Tandy , Commodore , and Apple , whose machines sold for several hundred dollars each and had become very popular. The microcomputer market was large enough for IBM's attention, with $ 15 billion in sales by 1979 and projected annual growth of more than 40% during the early 1980s. Other large technology companies had entered it, such as Hewlett-Packard , Texas Instruments and Data General , and some large IBM customers were buying Apples. As early as 1980 there were rumors of IBM developing

3965-406: Was essentially complete by April 1981, when it was handed off to the manufacturing team. PCs were assembled in an IBM plant in Boca Raton, with components made at various IBM and third party factories. The monitor was an existing design from IBM Japan ; the printer was manufactured by Epson . Because none of the functional components were designed by IBM, they obtained only a handful of patents on

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4030-540: Was initially developed for the IBM Datamaster , and was substantially better than the keyboards provided with virtually all home computers on the market at that time in many regards - number of keys, reliability and ergonomics. While some home computers of the time utilized chiclet keyboards or inexpensive mechanical designs, the IBM keyboard provided good ergonomics, reliable and positive tactile key mechanisms and flip-up feet to adjust its angle. Public reception of

4095-520: Was more than 30% per year. In a more limited study, the International Data Corporation estimated that the total amount of digital data in 2007 was 281 exabytes, and that the total amount of digital data produced exceeded the global storage capacity for the first time. A 2011 Science Magazine article estimated that the year 2002 was the beginning of the digital age for information storage: an age in which more information

4160-453: Was not available at release and was not released until March 1983. MDA scanned at a higher frequency and required a proprietary monitor, the IBM 5151 . The card also included a built-in printer port. Both cards could also be installed simultaneously for mixed graphics and text applications. For instance, AutoCAD , Lotus 1-2-3 and other software allowed use of a CGA Monitor for graphics and

4225-422: Was stored on hard disk drives. This was about twice the data produced in 2000. The amount of data transmitted over telecommunications systems in 2002 was nearly 18 exabytes—three and a half times more than was recorded on non-volatile storage. Telephone calls constituted 98% of the telecommunicated information in 2002. The researchers' highest estimate for the growth rate of newly stored information (uncompressed)

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