• Published 12th August 2026
  • Updated 13th August 2026
  • Est. Reading Time: ~18-22 minutes

45 years agone today, connected 12th August 1981, the computing scenery changed forever. IBM launched the Personal Computer, the alloy that kickstarted x86's fame successful computing astatine offices and homes alike. It was, of course, not a feat IBM achieved by itself - the IBM-compatible "clone" marketplace is what helped support the ecosystem salient successful the agelong run. But I for illustration to deliberation a large portion of its occurrence was its keyboard. Not the cleanable layout arsenic astir whitethorn agree, but surely a competent, well-built keyboard - the Model F/XT. Thus to celebrate, successful the astir due measurement for Admiral Shark's Keyboards, we will look astatine this keyboard, wherever it came from, and what it became. Of course, pinch discourse arsenic needed, including what led to the IBM PC, and some who and what was down it.

Contents

SCAMP prototype[1]
5100 Portable Computer[2]
5120 Computing System[3]

Before the PC, IBM released products adjacent to a individual computer, and toyed pinch the thought of a individual machine passim the 1970s. The PC's type number, 5150, places it successful the lineage of the 5100 Portable Computer, and the 5110 and 5120 Computing Systems. 5100 successful move is an improvement of a prototype machine known arsenic SCAMP (Special Computer APL Machine Portable), which was developed astatine the IBM Palo Alto Scientific Center successful 1973.[4] William C. Lowe, an executive successful the IBM General Systems Division (GSD) astatine the time, was considered instrumental successful foresting this prototype. The 5100 was touted arsenic a "personal computer" by immoderate successful the media, but it was a very costly and not accessible to galore people. It was notable for being portable though (for 1975), emphasised arsenic IBM's smallest computing strategy to day astatine that point.[5]

Aquarius concept[6]

Tommy R. Hardy, a now-veteran IBM designer, conceptualised immoderate interim ideas for a individual computer, including the "Yellow Bird" successful 1976 and the "Aquarius" successful 1977, some vaguely wedge-shaped successful a shape facet not dissimilar the later Commodore VIC-20, 64, etc., albeit bigger. Aquarius moreover made it to a pre-production prototype, but yet dismissed owed to deficiency of assurance successful its usage of bubble representation modules. When Atari's 8-bit computers launched successful 1979, IBM besides considered aquiring Atari and utilising the 800 arsenic a ground for the PC. Hardy besides conceputalised a pearl-white, IBM-branded 800 to this end,[6] but this thought proceeded nary further. The adjacent large thing, though, is Datamaster.

5324 Datamaster[9]

It would beryllium intolerable to person a chat astir the PC and its keyboard without talking astir the IBM System/23 Datamaster, an influential acquisition for IBM that aided them successful the PC's improvement and its keyboard. The 5322, the original "desktop" (all-in-one) Datamaster, was released successful July 1981. It was followed by the 5324 "floortop" (tower) Datamaster, announced connected 18th May 1982.[10] They were Intel 8085-based microcomputers intended to tally business applications written successful BASIC.

The improvement for Datamaster began successful February 1978, and its hardware was fresh by July 1980. However, arsenic recalled by IBM technologist David J. Bradley, who worked connected Datamaster, its motorboat was delayed by a twelvemonth and to conscionable a period earlier PC acknowledgment to IBM deciding to create the Datamaster's BASIC much successful statement pinch the IBM System/34 midrange computer's implementation of it.[11] The 5322's styling is attributed to Tommy R. Hardy via its U.S. creation patent (275,285), which was revenge connected 4th February 1980. The creation astatine that shape was mostly for illustration the vanished product, though the keyboard layout is somewhat different, pinch other keys and a non-stepped Enter key. If creation patents for 5324 exist, I was not capable to find them during my research.

5322 keyboard (top)[8]
5322 CSA (bottom)[13]

The Datamaster keyboard establishes the ground for each different keyboard discussed today. It is presently the earliest confirmed Model F keyboard implementation to make it to market, which would soon grow into an full family of IBM flagship keyboards salient for the first half of the '80s. They each usage capacitive buckling springs, a keyswitch creation by Richard Hunter Haris (U.S. inferior patent 4,118,611), wherever pressing a cardinal compresses a metallic coil outpouring underneath successful a measurement that it yet "catastophically" buckles, which successful move pivots a mini sheet made of a capacitive worldly atop a capacitance-sensing PCB called a "pad card".

The 5322 keyboard is simply a complete sub-assembly (CSA) that sits wrong the big Datamaster. The keys are arranged successful a layout derived from the Model B-based IBM 5251/5252 Display Station Typewriter Keyboard, which was IBM's astir contiguous and communal pre-Datamaster keyboard design. The aforementioned pad paper bears a 12x8 cardinal matrix and an Intel 8048 arsenic its controller. The keyboard uses a parallel-style interface wherever an inverted 7-bit scancode is sent crossed abstracted scanbit lines astatine erstwhile and together. Like its layout, its scancodes are besides derived from the 5250 family. On the receiving end, according to RetroAND (bitspassats.com), the Datamaster has an 8255 Programmable Peripheral Interface configured for mode 1 input. As the keyboard is wholly internalised, it connects straight to the 5322 motherboard (CPU planar board) via an 8x2 header.

5324 keyboard (top)[14]
5324 keyboard (bottom)[14]
5324 daughterboard (top)[15]
5324 daughterboard (bottom)[15]

As the 5324 is simply a distributed system, its type of the keyboard is discrete, connecting to its big via a DB-25-terminating cable. Chronologically, this was released aft the PC, truthful it derives its styling from the PC's keyboard, but pinch a considerably enlarged cover set and somewhat longer riser feet. It whitethorn sometimes beryllium confused pinch the IBM 5291/5292 keyboard besides discussed later, but the 5324 keyboard has the largest bezel betwixt them, to the constituent it sometimes gets nicked the "bezelmaster" Model F keyboard. The 5324 keyboard reuses the 5322's keyboard CSAs. But the 5324 keyboard adds a "keyboard adapter card" earlier its outer cable. As explained to maine by RetroAND, it has affirmative buffers and double negations for the power signals, apt to trim noise. In effect, it prepares a creation that was primitively integrated into something, to beryllium a distributed creation that requires a longer cable.

Personal Computer

An IBM Personal Computer (base unit)[16]

Roll backmost the timepiece to July 1980: Lowe - who was progressive pinch SCAMP - sounded the thought of a small, low-cost business and user machine to IBM CEO Frank Cary, who subsequently gave him a period to create a prototype and to motorboat the vanished merchandise successful a year. It was dubbed "Project Chess". Lowe was promoted soon after, truthful Chess fell to Philip Donald (Don) Estridge.[17][18] The squad consisted of astir 12 engineers, who were famously capable to create the PC extracurricular of IBM's emblematic processes, yet allowing them to meet the one-year deadline, alternatively than complete it successful 2 to 5 years for illustration astir different IBM systems of the time.

The earliest sketches of what became the PC, from 10th August 1980, were only comparatively precocious published. They show that a batch of what became the PC were nailed early on, including its usage of the Intel 8088, 5 description slots, 2 floppy diskette drives, usage of ASCII alternatively of EBCDIC, and a detached Model F-based keyboard. There are immoderate notable differences, of course, including the show controller, the powerfulness proviso unit's location wrong the PC, and that it primitively specified 8" floppy diskette drives alternatively of 5¼".[19] But each successful all, it is still recognisably the PC.

To execute their goal, the squad was besides assisted by anterior acquisition pinch processing Datamaster, and utilizing readily disposable components. The PC's usage of an Intel CPU, various Intel supporting controllers and timer, and 8-bit ISA autobus were derived from Datamaster's usage of akin technologies. The prime of an 8088 pinch 20-bit/1MB reside abstraction was mostly informed by woes pinch Datamaster's 8085 and its 16-bit/64KB reside space. The prime of 8088 complete 8086 was down to savings that could beryllium had by needing to support conscionable an 8-bit information autobus alternatively of 16.[11]

An IBM Personal Computer[16]

As you know, the IBM 5150 Personal Computer was released 45 years agone today. Its value cannot beryllium understated. Its unfastened architecture and usage of the 8086-sibling Intel 8088 established 1 of the astir celebrated and long-lived machine ecosystems. For amended aliases worse nowadays, the operation of it and a Microsoft-sourced operating strategy is still applicable acknowledgment to this. To maine personally, learning astir it and tinkering pinch its descendants are the backdrop to my method interests and knowledge. The PC was joined by the IBM 5160 Personal Computer XT (PC/XT) connected 8th March 1983. Over the original PC, the PC/XT adds a built-in difficult thrust and 3 description slots,[20] different being a very akin design. Whilst location are galore factors arsenic to why the PC succeeded, it was surely aided by the inclusion of a competent keyboard.

The IBM Personal Computer Keyboard[21]
Type 1 vs 2 F/XT (top)[22]
Type 1 vs 2 F/XT (CSA bottom)[22]

The IBM Personal Computer Keyboard is often colloquially referred to arsenic the "XT keyboard" aliases "Model F/XT", utilizing its relation pinch the PC/XT to differentiate it from the later IBM Personal Computer AT Keyboard ("Model F/AT"). Components of the F/XT tin besides beryllium referred to arsenic being "XT". At its core, the F/XT has a keyboard assembly overmuch for illustration the Datamaster's, but it adopted a caller serial-based protocol retroactively called IBM PC Mode 1 (also known arsenic the "XT keyboard interface"). It emits 9-bit information packets facilitating IBM scancode group 1. The keycap nomenclature was changed to ASCII style alternatively of EBCDIC. In the aforementioned sketches, the interface and nomenclature were decided from the beginning, but it was besides expected they whitethorn cost-save the creation by eliminating the leftmost usability cardinal bank,[19] which of people did not travel to fruition.

Two awesome variants of the original F/XT are known, some pinch their ain nuances and differences aliases similarities to the Datamaster keyboards. They are referred to arsenic Type 1 and Type 2.

Type 1 F/XT (top)[22]
Type 1 F/XT CSA (bottom)[22]
Type 1 F/XT pad card[22]
Type 1 F/XT controller daughtercard[22]
Type 1 F/XT imaginable information stamp[22]

The original design, Type 1, is very uncommon today. I person only seen examples pinch "81" day codes connected either its chips aliases stamped location wrong the screen set, truthful I ideate it was phased retired quickly successful favour of Type 2. What is absorbing is that IBM chose a different attack to Datamaster for its electronics. It has a 24x4 cardinal matrix, and the controller is divided into a capacitance-sensing driver and demultiplexer connected the pad card, and a abstracted daughterboard pinch an Intel 8048 arsenic its controller. The logic for this creation whitethorn beryllium explained by the IBM 5291/5292's beingness later.

A telltale motion from the extracurricular is that its original cable's 180° 5-pin DIN has nary achromatic integrative overgarment for illustration Type 2. The keyboard besides has a reset line, which the IBM PC Technical Reference implies was not used[23] and is wholly dropped by Type 2.

Another IBM Personal Computer[ASK]
Type 2 F/XT (bottom)[ASK]
Type 2 F/XT CSA (top)[ASK]
Type 2 F/XT CSA (bottom)[ASK]

The Type 2 creation is what astir F/XTs really are, and surely by the clip of PC/XT, the only 1 available. As already mentioned, their DIN plugs person a integrative overgarment and deficiency a reset line. But overmuch has changed internally too, possibly anarchonistic successful immoderate ways. It reverts to utilizing a 12x8 matrix for illustration Datamaster's, though configured differently. The controller is unified pinch the pad paper erstwhile again, though of people still implementing the IBM PC Mode 1 interface.

5291 Model 1 (illustration of)[24]

The IBM 5291 Model 1 Display Station and 5292 Color Display Station were some 5250-family terminals announced connected 6th September 1982. They are plug-compatible pinch the '70s IBM 5251 Display Station (model 11), [27][28] though the 5291 was intended arsenic a low-cost replacement and the 5292 arsenic a colour-enhanced supplement. 5291 Model 2 joined them connected 2nd October 1984,[29] which was functionally identical to 5291-1 but smaller, intended to beryllium much ergonomic, and pinch a relocatable screen, whereas 5291's was tightly integrated into the guidelines unit.

529X CSA (bottom)[30]
529X capsense driver[30]
529X feet (all extended)[ASK]
529X feet (various levels)[ASK]

The 529X keyboard is simply a nosy one. It's for illustration the F/XT but dialled up to eleven. It has sizeable bezels conscionable for illustration the 5324's, though pinch a somewhat smaller 'forehead'. But it besides has absurd three-setting riser feet, the longest of an IBM keyboard I person seen. Perhaps some of these facts lend themselves to the 529X keyboard's communal nickname - the "bigfoot" Model F. The cardinal nomenclature is backmost to being 5250-style fixed 5291's and 5292's application. The 529X keyboard CSA is the aforesaid arsenic the Type 1 F/XT's but without the controller daughtercard. Instead, the terminal itself would beryllium its controller, making the keyboards efficaciously "brainless" connected their own. This is wherever I tin spot why IBM designed the Type 1 F/XT otherwise from Datamaster, arsenic alluded to earlier - much constituent commonality betwixt higher-volume products. Both PC and (in my observations) astatine slightest 5291 were much truthful than Datamaster. Ultimately, the simpler, much elegant Type 2 solution won retired for PCs astatine least.

The 5291-2 and 5292 shared the aforesaid wholly detachable keyboard pinch a DA-15 plug astatine the extremity of it, dubbed the Type 2 529X keyboard. 5291-1's Type 1 was alternatively ever tethered, arsenic its cablegram connected to a 14-pin IDC-style header wrong the terminal, meaning the terminal has to beryllium opened to detach it. The Type 2 is typically the acold much communal of the 2 today.

Lexmark-produced rear label[31]
Lexmark-refurbed rear label[30]

Of each the keyboards discussed today, the 529X keyboard was produced the longest. Lexmark, which was founded from IBM Information Products Corporation's divestiture connected 27th March 1991,[32] produced 529X keyboards into astatine slightest mid-1994. This makes it 1 of the past Model Fs successful production. Lexmark besides refurbished existing 529X keyboards into 1996, their last twelvemonth successful the keyboard business. Lexmark-produced and Lexmark-refurbished 529X keyboards tin usually beryllium distinguished by the second being mislabelled "Model M" connected their rear labels alternatively of "F".

Portable Personal Computer

The IBM Portable Personal Computer[33]

On 16th Feburary 1984, IBM announced the 5155 Portable Personal Computer. It is fundamentally a PC/XT assembled into a luggable shape and fixed a tiny 9" amber CRT show and 1 aliases 2 now-half-height 5¼" floppy diskette drives.[34] It was IBM's reply to the Compaq Portable, 1 of the first IBM PC clones that launched conscionable nether a twelvemonth earlier and happened to beryllium successful the aforesaid shape factor.

Portable PC Keyboard (top)[ASK]
Portable PC Keyboard CSA (bottom)[ASK]

Compared to the original F/XT, the 5155's type is housed successful an all-plastic and two-tone screen group pinch a compartment to worldly its cablegram into, its guidelines sheet is simply a shiny, silvery aluminium alternatively of chromated steel, and it has a 6-pin modular plug alternatively of DIN. This results successful the keyboard being considerably lighter and sounding somewhat higher-pitched than the original. The screen group tin besides beryllium opened toolessly arsenic the acheronian integrative bezel surrounding the keys tin beryllium lifted astatine immoderate time. Electrically, the keyboard remains unchanged, and it tin beryllium passively adapted to 5-pin DIN if truthful desired.

When not successful use, the keyboard should beryllium mounted upright to the beforehand of the 5155, covering its full front. The keyboard has 2 clips towards the apical that are utilized to merchandise it and let it to pivot down. You tin additionally deploy its riser feet to wholly detach the keyboard from the big PC.

IBM 9001 (formerly CS/9000)[35]

The IBM Instruments Computer System 9000 (CS/9000, besides known simply arsenic the System 9000) was a Motorola 68000-powered laboratory machine introduced successful May 1982. It was notable for its vertical stack including an integrated printer/plotter and a 57-key membrane touch panel. On 21st February 1984, IBM introduced the System 9002 Desk-Top Computer and renamed the CS/9000 to the System 9001 Bench-Top Computer. In Q2 1985, the System 9003 Industrial-Floor Computer besides joined them.[36]

The 9002 was designed to beryllium a space-saving replacement to the now-9001, shedding the printer/plotter and integrating the membrane touch sheet into the keyboard itself (discussed much later).[37] The 9003 was intended for usage successful manufacturing and process power applications, being capable to run arsenic standalone aliases nexus pinch an IBM big processor via Systems Network Architecture (SNA). The full 9000 family was withdrawn effective 2nd December 1986,[38] arsenic yet each 3 members were unsuccessful successful their respective markets.

9001 Standard Keyboard (top)[39]
9001 Standard Keyboard (bottom)[40]

The CS/9000 and 9001 utilized the IBM System 9000 Standard Keyboard (part number 4780898), which was designed to beryllium connected apical of a protrusion from the big computer. The Standard Keyboard notably sports a rectangular "IBM System 9000" branding, nary flip-out riser feet, a cablegram that sprouts from the left, and a choke conscionable earlier the cable's DIN plug. Besides that, it is different the aforesaid and electrically compatible pinch the modular F/XT.

9002 Hybrid Keyboard[35]

The 9002's keyboard -the IBM System 9002 Hybrid Keyboard - is simply a batch much interesting, though. As aforementioned, this keyboard notably integrates the 57-key membrane touch sheet that was primitively connected the beforehand of the 9001 into the keyboard. Presumably, "Hybrid" refers to its quality of having some a buckling-spring keyboard and the touch panel. The resultant creation is very reminiscent of the IBM 104-key Model F Converged Keyboard utilized for the IBM 3290 Information Panel and 5085 Graphics Processor, pinch the sheet taking the spot of the 24-function-key slope but retaining its noticable bezels and two-stage riser feet. Despite this, the keyboard itself remains the F/XT-style assembly.

Whilst a 9002 machine has turned up successful caller times, the keyboard has not, nor are location immoderate photos of the keyboard from extracurricular the 1980s. No 1 that I cognize owns 1 to trial it aliases excavation inside, frankincense its electronics stay a enigma to me. In my 'professional' opinion, the 9002 Hybrid Keyboard is the rarest Model F keyboard known, possibly astatine astir tied pinch different keyboard I scheme to talk astir soon. At slightest each the different known variants person been contemporaneously pictured...

At present, the 9003 aliases its keyboard besides stay unseen to me. Computerworld's reporting suggests the keyboard and 57-key touch sheet were separate, conscionable for illustration the 9001.[41]

TPC and EMR

The IBM Tempest PC (TPC) family are IBM PC-related products that were designed aliases modified to suffice nether the TEMPEST program. TEMPEST is simply a NATO-recognised, United States National Security Agency specification regarding protecting against spying pinch physics equipment. In particular, qualifying systems are designed not to radiate electromagnetic emanations to antagonistic Van Eck phreaking. IBM referred to specified systems arsenic being 'TEMPESTed', usually adding typical covers and filters to meet the requirements. The TPC family yet included the IBM 4450 TPC1 (TEMPESTed PC), 4455 TPC2 (PC/XT), 4456 TPC3 (3270 PC), 4459 TPC4 (PC/AT), and 4460 TPC5 (3270 PC/AT).[42]

TPC1 and TPC2 so travel pinch an F/XT version named TPC Keyboard I and TPC Keyboard II, respectively, which contempt their sanction and portion numbers, do not disagree from each other. Additionally, an IBM EMR Keyboard and EMR Keyboard II are known, though it was unclear to maine what precisely those 2 were utilized for (ie., are they besides TPC family products aliases are they intended for TEMPESTed IBM systems extracurricular of the TPC family).

TPC1 CSA (bottom)[47]
TPC2 CSA (bottom)[44]

All 4 keyboards person clay covering the controller, hardier, non-coiled cables, and unsocial plugs compared to their 'civilian' counterparts. EMR I uniquely utilized a 180° 5-pin DIN plug not dissimilar the Type 1 F/XT's, whereas the different 3 (and TPCs 3 done 5) utilized a DE-9 connector instead. This intends EMR astatine slightest is not physically compatible pinch the known TPCs. EMR II, however, seems to beryllium identical to TPC1 and TPC2.

Regarding the PCs themselves, astatine slightest based connected Cathode Ray Dude's study connected the TPC4 and comparison pinch a modular PC/AT, they look to beryllium mostly arsenic you would expect from the modular models inside. The motherboard, powerfulness proviso and ISA paper complement were typical, and the differences laic pinch the reinforced outer casing, the powerfulness move location and function, and immoderate buffer abstraction betwixt the rear I/O and the existent backmost of the TPC.[49]

  • Big acknowledgment to RetroAND (bitspassats.com) for our communal conversations complete the past twelvemonth aliases truthful connected Datamaster, and their assistance pinch ensuring the facts surrounding Datamaster wrong this article and elsewhere are arsenic champion arsenic they could be.

Internal

External

ASK. Admiral Shark's Keyboards original content. License/note: CC BY-NC-SA 4.0.

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