IBM Model M

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Typical 1989 IBM Model M keyboard, part number 1391401. American 101-key QWERTY layout.
Unicomp Model-M with the Z button removed, the buckling spring below can be seen.
Removable keycap from a French Model M keyboard

The Model M keyboard refers to a computer keyboard genre that goes back to the "Model M" keyboard , which was manufactured by IBM millions of times between 1984 and 1999 . The model M keyboard was developed by IBM for its IBM Personal Computer designed and received the "Enhanced Personal Computer Keyboard" - key layout as an evolution from the 84-key AT keyboard design and the IBM 122-key terminal keyboard -Design. Originally produced by IBM in its own factories, later Model M keyboards were made to order by Lexmark and, to a lesser extent, by other manufacturers.

The vast majority of keyboards in this series are characterized by buckling springs and completely exchangeable key caps, but there are many different versions of this keyboard with partly different features. The Model M keyboards are very popular with prolific writers because of their precise pressure point and the associated tactile feedback. The series is also known for its robustness: Many of these keyboards, which have been in use since the mid-1980s, still work today and are still in use - in contrast to most other computer hardware from that time. The Model M also made the IBM "Enhanced" key layout popular in the PC sector, which is still used today, with the exception of minor modifications and extensions. The company Unicomp currently produces and sells Model M keyboards with spring-loaded keys under its own name.

Technical characteristics

Buckling spring torsional snap actuator : Illustration of the function of a buckling spring button (very similar to the one in the Model-M) from the original US patent US4118611 : Published October 3, 1978 , Applicant: IBM, Inventor: RH Harris. ‌
Force versus key travel diagram of a buckling spring key. At point 1C you can see the characteristic, sudden drop in the key counterforce when the spring is buckled / switched through, which acts as tactile feedback. There is also a hysteresis between pushing down and moving back. Figure 2 of U.S. Patent US4118611 : Published October 3, 1978 , Applicant: IBM, Inventor: RH Harris. ‌

A striking feature of the Model M keyboards is the “hard” keystroke with a pressure point (approx. 70 g key force), at which the counterforce suddenly decreases (to approx. 50 g key force). This generates tactile feedback to the user about the successful key operation. This positive property is realized by the buckling-spring technology , which also has a characteristic keystroke tone ? / i generated (acoustic feedback). With this clear double feedback, experienced writers can avoid unnecessarily pressing the key down to the bottom, potentially typing a little faster and making fewer mistakes. A coil spring is located under each button, which buckles under the pressure of the operator's finger, triggering a hammer that presses two electrically conductive plastic foils / membranes together and thus establishes the switching contact. Audio file / audio sample

The keyboards are unusually heavy by today's standards, but they are also stable, which is achieved by using a sheet steel plate as an internal support. The key caps are often removable and therefore easy to clean. The inscription is permanent as dye sublimation introduced ( "dye sublimated") deep into the cap of plastic. The key caps are made of high-quality PBT plastic material and are therefore more resistant to wear and yellowing than other materials such as ABS (a common material on current keyboards). The keys were specified for 25 million keystrokes , which for a prolific writer with 100 keystrokes per minute , eight-hour day and 250 working days would mean a service life of more than 10 years even for the most frequently used "E" key . The motivation for this elaborate technology was that at the time of the introduction of the Model M PCs and terminals were still competing with high-quality typewriters ( above all the IBM Selectric ) and the changeover to the new technology should be made easier for users through a comparable typing experience.

With the Model M, the IBM "Enhanced Personal Computer Keyboard" layout was also introduced in the PC area, which, in contrast to the previous IBM PC keyboards (such as the AT keyboard ), had a significantly modified and expanded key layout. For example, the F11 and F12 keys and a separate function key block have been added next to the numeric keypad , and important keys have been enlarged (Shift and Return) or arranged more ergonomically on the keyboard. It is believed that IBM tried with the "Enhanced" keyboard layout to consolidate its keyboard production, which was split between several terminal keyboard layouts and the PC keyboard layouts (each with international variants). In the future, a keyboard design should cover both use cases, the terminals also with terminal emulators, for example. Instead, IBM primarily adopted the basic terminal design for the "Enhanced" -101/102 key layout (but only 12 instead of 24 F keys) and the LEDs from the AT keyboard. The "Enhanced" design also integrated the typically 102-key international keyboard layouts (such as the German " QWERTZ ") as an option for the 101-key basic design, which also helped save costs.

There are, however, some disadvantageous features of the Model M design as well. Model M keyboards are quite heavy (approx. 2.5 kg in the first generation) and therefore not very portable. Due to the loud switching noise, they are only partially suitable for volume -sensitive areas such as libraries or open- plan offices. Although the keyboards are very robust against dry dirt, liquids remain in the keyboard and stick to the membranes (later softened by drainage channels). With a "2 key rollover" design, in the worst case only two keys pressed at the same time can be correctly identified via scan codes (however, through a clever design, all common 3- key combinations were ensured). A Hitachi - or Motorola-6805 - microcontroller converts the scan codes . Ultimately, the Model M also has a film- based structure, no mechanical buttons per key and is therefore not a real "mechanical keyboard" (even if it behaves like one in many ways). It is also difficult to service and repair because the case is locked with unusual 7/32 inch (5.5 mm metric ) hex screws and the inner circuit board is closed by plastic rivets . If the rivet heads are removed in order to get to the keyboard foils, they inevitably have to be replaced with screws and nuts, which is expensive. The Model M also requires significantly more power than current keyboards, approx. 120 mA and 40 mA for the three LEDs . This becomes an issue when a passive PS2 - USB - Interface adapter is used which does not expect such a load or insufficient possible with USB 500 mA for reliable operation. However, there are active PS / 2-USB converters that work with the Model M; Unicomp also later included Model-Ms with a native USB interface in the program.

history

The Model M was developed as a cost-effective replacement for the Model F design (used e.g. in the AT keyboard ). As the core of the model M is a membrane-buckling spring-button assembly (engl. Was chosen membrane Buckling Spring ), a patented IBM design. The previous patent for a capacitive buckling spring button (as used in the Model F) was applied for by IBM employee Richard Hunter Harris on August 30, 1977 under the name Buckling spring torsional snap actuator and patent number 4118611 at the American USPTO , the patent was granted on October 3, 1978. The subsequent patent US4528431 for the diaphragm spring button for the Model M ( rocking switch actuator for a low force membrane contact switch ) was granted on July 9, 1985.

Production of the original Model M began in 1985, and the keyboards were often sold in bundles with IBM computers throughout the 1980s . They were manufactured by IBM in its factories in Lexington (USA), Greenock ( Scotland ) and Guadalajara ( Mexico ). Until 1987 the keyboards had a detachable AT cable, after which they were provided with a detachable PS / 2 cable. The flexible coiled cables were available in lengths of 5 and 10  feet (about 1.5 and 3 m). Three color variants were produced in larger numbers: white-beige (undyed), industrial gray and black.

In March 1991, IBM began outsourcing parts of its hardware manufacturing facilities , including keyboard manufacturing, to investment firm Clayton & Dubilier , to form Lexmark International . The Model M-Keyboard was further manufactured by Lexmark (for especially IBM) in the United States and Mexico and by IBM itself in Scotland. Many of these keyboards have the IBM production numbers 52G9658, 52G9700, 82G2383, 42H1292.

The price for a Model M with Trackpoint was $ 159 in 1993, which, adjusted for inflation, corresponds to about $ 253 in 2012 (approx. € 193 at the end of 2012).

As of 1994, the majority of Model M keyboards were made simpler to meet the growing price pressure in the market. The simplifications included lighter-weight plastic parts, a permanently attached cable, a thinner steel plate and only single-color key printing. Small improvements have also been made, however, such as the addition of liquid drainage channels to the bottom of the case. Overall, changes to the structure of the classic Model M have been made in four generations. The most frequently produced variant with the production number 1391401 is a keyboard with a US English key layout for the IBM PS / 2 interface in white- beige .

On October 3, 1995, the buckling spring patent US4118611 expired, the patent for the diaphragm buckling spring button on July 9, 2002, 17 years after the grant. The last patent on the Model M probably expired in 2004.

In 1996, Lexmark's contractual commitment to manufacture keyboards for IBM expired, and Lexmark ceased manufacturing. Lexmark sold the production machines and patents to some of their employees, who founded Unicomp in Lexington and continued production. The Unicomp variant of the Model M, which is similar to the IBM model 42H1292 and was first referred to as 42H1292U and later as "Customizer", is still in production (as of 2013). When Lexmark stopped production for IBM, IBM continued to manufacture keyboards in its remaining Scottish factory and outsourced the production of the M13 Trackpoint II keyboard to Maxiswitch. Production by Maxiswitch ended in 1998, that by IBM in 1999.

As the only model M-producer from the 2000s remained, Unicomp led modernized variants with native USB port as well as enhancements to the IBM Enhanced -Tastenlayouts to have become customary now Windows key one.

reception

The contemporary reception was predominantly positive, even if the keyboard layout, which was significantly changed compared to the previous 84-key AT PC keyboard, was criticized. For example, in 1986 John C. Dvorak from Infoworld criticized the new layout introduced by IBM as the "Enhanced Personal Computer Keyboard" , but concluded positively with "It's still the best" feeling "keyboard in the world." ("It is still the best-feeling keyboard in the world") The "Enhanced" 101/102 key layout introduced by IBM prevailed in the PC area with the Model M and defined all subsequent PC keyboard layouts Layouts to this day, which are typically only gradual variations of this layout.

The IBM Model M was retrospectively praised by many recipients as a timeless and enduring hardware design and also referred to as "the best keyboard ever built". For example, Eric S. Raymond came out as a big Model M fan and called it a "classic".

The Model M is still considered a reference against which current mechanical keyboards measure themselves or are based on design, e.g. B. Cherry's tactile MX Green button at the introduction.

Model-M case modification in steampunk style.

There is an extensive community of enthusiasts who deal with the properties, maintenance and customization ( modding ) of Model Ms. Typical modifications begin with simple color adjustments, through replacing the plastic rivets with screws, through noise level reductions to complete conversions of the housing, e.g. B. in steampunk style.

Although Unicomp continues to produce replicas , the original IBM and Lexmark variants have maintained their value among keyboard enthusiasts and are traded second-hand at prices like new high-quality keyboards (approx. 80 €). In the 14 years of production of the Model M by IBM, a large number of variants were produced, some of which are now extremely rare and valuable.

In the mid-2000s, some commentators spoke of a (small) comeback of the Model M keyboard in connection with the Unicomp Buckling Spring keyboards.

Functions by article number

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.
item number Key type Interchangeable connection Drainage channels Label type / position Manufacturer Period of manufacture copyright Additional functions
Keycaps electric wire
1370477 Buckling spring No Yes PS / 2 Yes blue, left corner Lexmark ? –1995–? Lexmark International, Inc. 1984
1370478 Buckling spring Yes Yes PS / 2 Yes blue, left corner Lexmark 1993 Lexmark Int'l. Inc. 1984 M-5, trackball. Left and right click, and L / R "drag" buttons.
1386085 Buckling spring Yes Yes AT No Gray, left corner IBM 1988 IBM Corp. 1984 English layout.
1389979 Buckling spring Yes Yes AT No silver, right corner IBM 1986-1987 IBM Corp. 1984 No LED lights for Num / Lock / Roll. Swedish layout.
1390120 Buckling spring Yes Yes AT No Silver, right corner IBM 1986-1987 IBM Corp. 1984 No LED lights for Num / Lock / Roll
1390131 Buckling spring Yes Yes AT or PS / 2 No silver, right corner IBM 1986-1987, 1993 IBM Corp. 1984
1390133 Buckling spring Yes Yes AT or PS / 2 No silver, right corner IBM ? –1986–1987 IBM Corp. 1984 German QWERTZ layout
1390148 Buckling spring Yes Yes XT No silver, right corner IBM ? –1986–1987 IBM Corp. 1984 No LED lights for Num / Lock / Roll. German QWERTZ layout
1390639 Buckling spring Yes No XT ? silver, right corner IBM ? –1987–? IBM Corp. 1985 Spanish QWERTY layout
1391401 Buckling spring Yes Yes AT or PS / 2 no (yes 1992 and later) gray (blue 1992 and later), left corner IBM 1984-1996 IBM Corp. 1984
1391402 Buckling spring Yes Yes PS / 2 Yes ? gray (blue 1992? and later), left corner IBM UK 1991–1996–? IBM Corp. 1985 French AZERTY layout
1391403 Buckling spring Yes yes (no 1994 and later) AT or PS / 2 Yes gray, left corner or blue, left corner IBM UK / Lexmark International 1986-1998 IBM Corp./Lexmark International Inc. 1985 German QWERTZ layout
1391404 Buckling spring Yes Yes AT or PS / 2 No gray, left corner IBM UK 1986–? IBM Corporation (no year on label) Italian QWERTY layout
1391405 Buckling spring Yes Yes AT or PS / 2 No Black / blue, left corner IBM 1986–? IBM Corp. 1985 Spanish QWERTY layout
1391406 Buckling spring Yes Yes AT or PS / 2 No gray, left corner IBM ≤ 1985-1996 IBM United Kingdom British 102-key variant
1391407 Buckling spring Yes Yes PS / 2 Yes gray, left corner IBM ? –1994–1996–? IBM United Kingdom Danish / Icelandic 102-key variant
1391409 Buckling spring Yes Yes PS / 2 No gray, left corner IBM 1989–1992? IBM Corp. 1985 Norwegian 102-key variant
1391410 Buckling spring Yes Yes PS / 2 (or AT?) No ? IBM UK ? –1992–? IBM Corp. 1985 Portuguese 102-key variant
1391411 Buckling spring Yes Yes AT or PS / 2 No gray / blue, left corner IBM UK ? –1987–1997–? IBM Corp. 1985 Swedish 102-key variant
1391414 Buckling spring Yes No PS / 2 No gray / blue, left corner IBM UK ? –1998–? IBM Corp. 1985 Belgian AZERTY layout
1391412 Buckling spring Yes Yes AT or PS / 2 No gray, left corner IBM UK 1987-1996 IBM Corp. Swiss-French / German QWERTZ layout, 102-key variant
1391472 Buckling spring Yes Yes AT or PS / 2 No gray, left corner IBM 1987-1991 IBM Corp. 1984 space-saving; no numeric keypad and no lamps
1391506 Buckling spring Yes Yes PS / 2 No gray / blue, left corner IBM de Mexico 1990 IBM Corp. 1984 Spanish QWERTY layout
1391511 Buckling spring Yes Yes PS / 2 No blue, left corner IBM UK 1990-1993 IBM Corp. 1985 Dutch 102-key variant
1392565 Buckling spring Yes No 8P5C (RJ-45) Yes gray, left corner Lexmark (for IBM) ? -1995 Lexmark International, Inc. 1984 Keyboard for terminals like the IBM 3151. Modified layout for special functions
1392934 Buckling spring Yes Yes AT or PS / 2 No gray, left corner IBM 1990 IBM Corp. 1984 space-saving; no numeric keypad and no lamps
1393464 Buckling spring Yes Yes PS / 2 no (?) gray, left corner IBM ? –1987–1989–? IBM Corp. 1984 Just like 1391401, with special keycaps: Made for flight bookings
1393669 Buckling spring Yes Yes PS / 2 No blue, left corner Lexmark UK / IBM UK 1994-1995 Lexmark International Inc. 1985 / IBM Corp. 1985 Croatian QWERTZ layout; Loudspeaker opening on the bottom
1394064 Buckling spring Yes Yes PS / 2 No ? Lexmark ? –1996–? Lexmark International, Inc. 1984
1394540 Buckling spring Yes Yes PS / 2 No gray, left corner IBM 1990–1991? IBM Corp. 1984 Made for IBM RS / 6000 computers. Includes speakers.
1394542 Buckling spring Yes Yes PS / 2 Yes gray / blue, left corner IBM UK / Lexmark UK 1990-1994? IBM Corp. 1985 / Lexmark International Inc. 1985 German QWERTZ layout
1394958 Buckling spring Yes Yes PS / 2 Yes silver on black, left corner IBM UK 1989-1998 IBM Corp. 1985 German QWERTZ variant, dark gray industrial version
1394966 Buckling spring Yes Yes PS / 2 ? silver on black, left corner IBM UK ? –1992–? IBM Corp. 1985 Swedish 102-key version, dark gray industrial version
1395300 Buckling spring No No PS / 2 No blue, upper right corner IBM 1990-1993 IBM Corp. 1984 Model M2; Delivered with IBM PS / 1
1396790 Buckling spring Yes Yes PS / 2 Yes blue, upper left corner IBM ? –1992–1999? IBM Corp. 1985 Made in the UK by IBM; North American layout
1397003 Buckling spring Yes Yes PS / 2 Yes blue, top left IBM ? –1993–1999? IBM Corp. 1985 Made in the UK by IBM; German QWERTZ variant; 122 keys
1397599 Buckling spring Yes Yes PS / 2 Yes gray, left corner IBM ? –1993–? IBM Corp. 1984
1397681 Buckling spring No Yes PS / 2 (or AT?) Yes blue, left corner IBM ? –1992–1993–? IBM Corp. 1984 space-saving, no numeric keypad and no lamps
1399625 Buckling spring Yes No PS / 2 Yes blue, left corner Lexmark, IBM UK ? –1994–? Lexmark International Inc. 1985 Terminal keyboard; Speaker opening on the bottom; no lamps
13H6705 Buckling spring No No PS / 2 Yes silver, left corner Lexmark 1995-1998 Lexmark International, Inc. 1984 Trackpoint, two connections for keyboard and mouse, the only model M in black
42H1292, 92G7453, 92G7483 Buckling spring Yes No PS / 2 Yes blue, left corner Lexmark, IBM UK 1993-1999 Lexmark International, Inc. 1984
42H1292U Buckling spring Yes No PS / 2 Yes blue, left corner Unicomp 1996 – today Unicomp, Inc. 1984 Optional AT / DIR adapter
51G8572 Buckling spring Yes Yes PS / 2 Yes gray / blue, left corner IBM, Lexmark, IBM UK 1993-1996 IBM Corp. 1984 / Lexmark International, Inc. 1984 Model M; shipped with IBM RS / 6000; Speaker on the bottom
52G9658 Buckling spring Yes No PS / 2 Yes blue, left corner Lexmark ? –1993–? Lexmark International, Inc. 1984 Model M; Loudspeaker opening on the bottom
52G9700 Buckling spring Yes No PS / 2 Yes blue, left corner Lexmark 1993-1999 Lexmark International, Inc. 1984
70G8638 Rubber bell No No PS / 2 Yes Edge, top right Lexmark ? –1994–? Lexmark International. Inc. 1984 Speaker opening on the bottom, screen-printed keycaps
71G4621 Rubber bell Yes No PS / 2 Yes blue, left corner Lexmark (for IBM) ? –1996–? Lexmark International, Inc. 1984 Danish QWERTY layout
71G4625 Rubber bell No No PS / 2 Yes gray, left corner Lexmark (for IBM) ? –1993–1996–? Lexmark International, Inc. 1984 German QWERTZ layout
71G4643 Rubber bell Yes No PS / 2 Yes blue, left corner Lexmark ? –1995–? Lexmark International, Inc. 1985
71G4644 Rubber bell No No PS / 2 Yes blue, left corner Lexmark ? –1993–1995–? Lexmark International, Inc. 1984
8131276 Buckling spring No No RJ25 Yes blue, upper right corner IBM UK ? -1996 IBM Corp.
82G2383 Buckling spring Yes No PS / 2 Yes blue, left corner Lexmark 1993-1999 Lexmark International, Inc. 1984
82G3281 Buckling spring No No PS / 2 Yes ? Lexmark 1994-1995 Lexmark International, Inc. 1984 white trackpoint, two connections for keyboard and mouse
06H4173 Buckling spring No No PS / 2 Yes ? Unicomp 1998-1999 Unicomp, Inc. 1984 Industrial PS / 2 trackpoint, two connections for keyboard and mouse
UB40R46 Buckling spring No No PS / 2 Yes ? Unicomp ?-today Unicomp, Inc. 1984 104 keys, customizable layout.
UB4044A Buckling spring No No USB Yes no Unicomp ?-today Unicomp, Inc. 1984 104 keys, customizable layout (USB version).
02K3817 Buckling spring Yes No PS / 2 Yes no Unicomp ?-today Unicomp, Inc. 1984 Unicomp keyboard with German layout
UNI0T56 Buckling spring No No PS / 2 Yes no Unicomp ? –2003–? ? 122 keys made for PC / 5250 emulators
item number Key type Interchangeable connection Drainage channels Label type / position Manufacturer Period of manufacture copyright Additional functions
Keycaps electric wire

gallery

  • Origin of the "Enhanced" 101 keyboard layout on the Model M (above): the 84-key IBM AT keyboard (lower left) and the IBM 122-key terminal keyboard (lower right).

  • A model M from 1995, item no. 1391403 with a blue logo. German 102-key QWERTY layout.

  • Back of a Model M from 1994, item no. 1394542 from Lexmark production. At the top are the four unusual and deeply countersunk 5.5 mm hex screws . In the middle the identification label.

  • Label with part and serial number from 1994, item no. 1394542 from Lexmark production. At the bottom, the signatures of Lexmark employees after assembly and functional tests.

  • IBM Model M Space Saver (without numeric keypad ) from the side, the clearly curved, ergonomically shaped keyboard surface of all Model M.

  • IBM Model M SpaceSaver inside view, back: the steel plate in the middle and the scancode board on top. You can also see the approx. 50 plastic rivet heads, distributed on the steel plate, connecting the keyboard foils and key housings.

  • IBM Model M industrial version in gray. "SpaceSaver" variant without numeric keypad with 84 keys

  • Unicomp "Customizer" variant of the IBM Model M Keyboard

  • Close-up of a current black Unicomp "Ultra Classic" Model-M keyboard.

  • A model M that has been repositioned to a Dvorak layout , easy to carry out thanks to the removable keycaps.

Web links

Commons : IBM Model M Keyboard  - collection of images, videos and audio files
  • Unicomp - current Model M manufacturer (English)
  • IBM Model M - in the deskthority.net specialist wiki (English)

Individual evidence

  1. ↑ Felix Knoke: Keyboard legend: machine gun in the open plan office . 2008. Accessed on June 19, 2012: “ More than 20 years ago, IBM developed the M model, which prolific writers nowadays buy at high prices on the Internet - or happily find it in bulky waste. Your keystroke is legendary [...] "
  2. ↑ Development of a membrane switch-type full-travel tactile keyboard  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. from IBM@1@ 2Template: Dead Link / www.research.ibm.com  
  3. ↑ A Passion for the Keys: Particular About What You Type On? Relax - You're Not Alone. LOOSE WIRE, By JEREMY WAGSTAFF, Wall Street Journal , November 23, 2007
  4. ↑ a b Andrew Preater: Care and feeding of the IBM Model M keyboard ( English ) www.preater.com. June 10, 2010. Retrieved June 19, 2012.
  5. ↑ IBM Model M Product Description (English)
  6. ↑ 100 * 60 * 8 * 250 * 0.17 = 2.04 million keystrokes on the "E" key per year
  7. ^ A b John C. Dvorak: IBM trips up with its revamped keyboard ( English ) Infoworld. S. 6 April 2, 1986. Retrieved January 1, 2014: " It's still the best" feeling "keyboard in the world. "
  8. ↑ why-im-using-1988-keyboard (English, June 2012)
  9. ↑ Benj Edwards: Inside the World's Greatest Keyboard ( English ) PC World . July 8, 2008. Retrieved December 24, 2013.
  10. ↑ Ripster's Nut and Bolt Mod (English, February 2012)
  11. ↑ IBM PS / 2 Keyboard Modification ( Memento from February 28, 2008 in the Internet Archive ) (English, 2008)
  12. ↑ Buckling spring torsional snap actuator by Richard Hunter Harris / IBM (English)
  13. ↑ Rocking switch actuator for a low force membrane contact switch Edwin T. Coleman, III / IBM (English)
  14. ↑ 1991 ( English ) In: Archives . IBM. Retrieved December 31, 2013.
  15. ^ Peter H. Lewis: The Executive Computer; Can IBM Learn From a Unit It Freed? . In: The New York Times , December 22, 1991. Retrieved May 13, 2010. 
  16. ↑ Bernard Levine: Keyboard vendors punched on prices . In: Electronic News . 
  17. ↑ Brandon Ermita: Originally, how much was the model M keyboard in 1986 dollars? ( English ) clickeykeyboards.com. Retrieved December 31, 2013: " Excerpt from Orange County Register California, December 13, 1993." IBM to put Trackpoint on full-sized keyboards (presumably this refers to IBM model M13) IBM and Lexmark International, an IBM spinoff that still makes the company's keyboards, are accepting orders for Trackpoint keyboards through their telemarketing operations. IBM sells its version for $ 159 ... Lexmark's keyboard is $ 149. " $ 159.00 in 1993 had the same buying power as $ 252.87 in 2012. Annual inflation over this period was 2.47%. "
  18. ^ Lexmark International Reports Best Year Ever Since Independent of IBM . In: Business Wire , December 12, 1994. 
  19. ↑ model M related patents (English)
  20. ^ Keyboard for a computer, Myron F. Davis, Jr. et al. (English, 1987)
  21. ↑ Keyed In: Unicomp has the right touch ( Memento from January 2, 2014 in the Internet Archive ) in BusinessLexington by Margaret Buranen (July 18, 2012, English)
  22. ↑ IBM Enhanced Keyboard from a review of the IBM Personal Computer Family, Vol. 3, No. 1. (English)
  23. ↑ The Best Keyboard You've Ever Typed On ( English ) Life hacker. Retrieved December 1, 2013.
  24. ↑ Inside the World's Greatest Keyboard ( English ) In: PC World . Retrieved December 1, 2013.
  25. ↑ The world's best keyboard, and why it's so great ( English ) PC advisor. Retrieved December 1, 2013.
  26. ↑ IBM Model M: The One True Keyboard ( Memento from March 10, 2007 in the Internet Archive ) on lowendmac.com by Tommy Thomas (May 12, 2009)
  27. ↑ Eric S. Raymond : The Model M: A timeless classic ( English ) esr.ibiblio.org. July 7, 2010. Retrieved January 1, 2014: “ I feel about the Model M the way I feel about the 1911-pattern .45 pistol and the core design of Unix. All three of these are too frequently dismissed as dinosaurs, but stand out to the discerning as timeless classics of square-shouldered ruggedness and fitness-for-purpose whose virtues, it seems, need to be rediscovered anew in every generation. [...] As such, the Model M (and all engineering designs at that level of excellence) are worth celebrating. "
  28. ↑ Eric S. Raymond: Announcing: Keyboards with crunch. In: esr.ibiblio.org . June 23, 2013 (English).
  29. ↑ Cyril Kowaliski: A first look at Cherry's MX green key switches - Eat your heart out, buckling springs ( English ) techreport.com. March 7, 2013. Retrieved December 31, 2013: “ In both feel and specifications, though, the greens are closer to the buckling spring switches of IBM's iconic Model M keyboards. "
  30. ↑ Trivia, Model M & F (English)
  31. ↑ Modding the IBM Model M Keyboard (English)
  32. ↑ Modifications: IBM Model M: Nut and Bolt Mod (English)
  33. ↑ Model M floss mod (English)
  34. ↑ So, I greased up my Model M (English)
  35. ↑ Steampunk Keyboard Mod (English)
  36. ↑ Old-School Keyboard Makes Comeback Of Sorts on npr.org by Martin Kaste (January 30, 2009, English)
  37. ↑ Product Review: Unicomp Customizer keyboard, or, the IBM Model M reborn by Jake Seliger (May 7, 2008, English)