Yes, you’re reading that headline correctly: IBM’s legendary Model M turns 40 this year.
The keyboard that gave us the standardised layout on both sides of the Atlantic, with its quintessential 100% form factor and classic buckling spring mechanical keys (in most instances), is about to have its midlife crisis. In typical fashion, it’s off to buy an expensive convertible.
There’s no doubt that the Model M is a true icon that’s adorned the desk of many PC users over the years, including plenty of film appearances. It makes sense, therefore, to take a look at where we’ve come from and how the classic legacy of this keyboard lives on decades later.
The Model M started out as a replacement for IBM’s Model F keyboard that was previously bundled with its terminals. That became too expensive to produce, so IBM looked to replace it with a «low cost, high volume» alternative: the Model M.
The first Model M (or then, the IBM Enhanced Keyboard) was the keyboard IBM threw in with its 3161 model terminal and, outside of the typewriter and industrial models, is the genesis for the keyboard in the mainstream with the features that have become ubiquitous elsewhere, most notably key placement for things like the Control and ‘inverted T’ arrow keys.
A lot of these decisions reportedly had IBM’s Human Factors Research Groups involved to find the most efficient way for typists to use a keyboard by allowing them to move keys around, enlarge, or duplicate them, and what resulted is essentially the full-size keyboard layout we have today. Both the ISO and ANSI standard layouts were finalised ten to fifteen years after the Model M’s inception and only made minor changes, such as adding the Windows and Menu keys.
To understand a little more about the genesis of the Model M, I took some time a couple of weeks ago and sat down with Don Bowman, the vice president of development at Unicomp, and someone who has been involved with IBM, Lexmark, and Unicomp for the last four decades. Bowman’s time goes way back, covering the keyboard side of the business at Unicomp and the typewriters and printers at IBM and Lexmark respectively.
According to Bowman, IBM decided to integrate the individual buckling spring switch assemblies used into one frame, which significantly reduced the part count and associated costs, while preserving the advantage of its infamous buckling spring switch. As per the extensive resource on the Model M from Sharktastica, IBM changed the way the switches were sensed—changing to a membrane assembly rather than a capacitive pad card (as with the Model F) cut costs in half according to the 1983 patent for membrane buckling springs, so was likely a huge money saver for IBM.
Combine this with the introduction of IBM’s Personal System 2 of computers (or PS/2,where the connector gets its name from), which shipped with proper Model Ms and sold in droves, and you quickly got a keyboard that had a lot of uptake and became a favourite.
