Don Estridge (1937-1985)
http://www.computinghistory.org.uk/det/1788/Don-Estridge/
Don was the father of the IBM PC, and it is due solely to Don that the PC was launched with a totally open hardware architecture that allowed companies such as AST to produce cards such as the "6-Pack" (so-called since, on a single card, it included serial ports, parallel ports, additional memory etc. - available as discrete components from IBM).
Don also decreed the totally open software architecture: a program listing of the code was included in the Technical Manual. Which led to the situation - since the code (and the bugs in the code) were copyright - wherein the clone manufacturers had to emulate the bugs (for compatibility) without actually copying the exact code ... :)
Don was way ahead of his time, especially where IBM & the PC were concerned, He realised that the IBM clients preferred to purchase from a single supplier - especially if one had a "valued client" (or some such) licencing agreement - and so were not interested in products from Apple but were rather waiting for a similar product from IBM.
So, so the story goes, he nagged the IBM board until they reputedly allowed him to manufacture the PC, if nothing other than him quiet.
The rest, as they say, is history.
He unfortunately died in an 'plane crash, just as his vision was bearing fruit. One wonders what the PC world would be like today if he were still alive.