This post brought back some ancient memories … and I’m always amazed how far we’ve got in the last 30 years. For me, it all started with an IBM 360, having 48K (forty eight kilobytes) of core memory in which it ran an operating system and three user partitions. Fortran IV was the only programming language and card reader the only input device.
Moving to a VAX 11/780 was a major improvement; it was a multitasking environment with real terminals. VAX was an interesting beast: the first step in the boot process was to start an embedded PDP-11 processor that read an 8” floppy disc and uploaded the microcode to the main CPU. The only drawback was that 30 users had to share 2M (two megabytes) of main memory and so I couldn’t crash the machine whenever I wanted.
A few years later, I managed to get access to a really cute research PDP-11 running RSX-11M. Finally I could start writing device drivers and kernel code without risking the wrath of dozens of users years older than myself. And then the personal computers appeared and I probably made one the best choices I could – the BBC Micro from Acorn. It was never popular, but it had an amazingly well-designed operating system that you could extend in any way you wish (and even symbolic assembly language built into its BBC BASIC).