Aaah yes, IBM. International Business Machines. The company that nearly didn't bring us the Personal Computer in 1981....like Digital, they weren't too interested until Microsoft gave them a year's exclusive licensing for MS-DOS, and even then the punters weren't too interested for several months. After all, they had their smart spiffy CP/M machines with all their applications - why divert onto something new and different that didn't even come with a floppy drive?
Eventually though, IBM's persistence paid off and the PC became the machine to keep up with and copy. Problem was, in earlier machines the BIOS (Basic Input/Output System - the ROM code that runs self tests and boots the machine) was on the boot disk....with the IBM PC it was in ROM on the motherboard and copyrighted to IBM, so to copy the machine you had to copy the ROM....a distinct no-no. Compaq were the first to produce a ROM based BIOS that didn't stamp on IBM's copyright, and the term 'IBM compatible' was coined.
Of course, there's much much more to IBM than the 5150 PC, but that's addressed in enough detail elsewhere on the World Wide Wait; remember I'm concentrating on home machines here.
Model 5150 - the very first IBM PC, complete with keyboard and colour monitor. Excellent donation from David Norman - thanks! Model 5161 expansion unit for the 5150 with extra cards and an IBM hard drive, also from David. Model 5150 with monitor and keyboard, upgraded with bigger PSU, colour graphics and hard drive.
PS/2 Model 40LX laptop, boxed complete. Pix soon