45 Years On: How the IBM PC and Its Model F Keyboard Set the Template

On August 12, 1981, IBM shipped the 5150 Personal Computer and, with it, cemented the x86 architecture and the general shape of what people still call a PC. The machine’s staying power owed less to IBM alone than to the compatible-clone market that grew around its open, off-the-shelf design—but the launch hardware set the template. That included the Model F/XT keyboard, whose capacitive buckling-spring switches (Richard Harris’s design, in which a compressed coil spring buckles and pivots a capacitive plate over a sensing PCB) gave the PC a genuinely well-built input device even if the layout was imperfect.

The 5150 didn’t emerge from nowhere. IBM had circled personal computing throughout the 1970s, from the 1973 SCAMP prototype and the pricey, portable 5100 to unshipped concepts like the wedge-shaped “Aquarius” (killed over doubts about its bubble memory) and even a scheme to rebadge an Atari 800. The pivotal precursor was the System/23 Datamaster, an Intel 8085-based business microcomputer whose keyboard was the first Model F to reach market and whose component choices directly informed the PC. Frustration with the Datamaster’s 8085 and its 64KB address ceiling pushed the team toward the 8088, chosen over the 8086 to cut costs while gaining a 1MB address space.

The PC itself was built by “Project Chess,” a roughly twelve-engineer team first pitched by William Lowe and then led by Don Estridge, which was allowed to work outside IBM’s normal processes to hit a one-year deadline instead of the usual multi-year cycle. Sketches from August 1980 show most of the final design locked in early—the 8088, five expansion slots, dual floppy drives, ASCII rather than EBCDIC, and a detachable Model F keyboard—with only details like the display controller, power-supply placement, and a shift from 8-inch to 5¼-inch diskettes still to change. It’s a reminder of how much of modern computing traces back to a small team’s deliberate break from corporate convention.