Unix is widely extolled as the first portable operating system but many don’t know how that came about. By the time of Version 6, Unix had been licensed to many universities but it still ran only on the PDP-11 family of computers. Juris Reinfelds tells the story of how the University of Wollongong made the first port of Unix to a non-PDP system.
It’s an interesting story. The small Computer Science section—it was part of the Mathematics Department then—needed a time share system for hands on computing by students and staff. Reinfelds visited Murray Allen and John Lions1 of the University of New South Wales to discuss possible systems. He early on decided that a Unix system would be ideal but the CS section didn’t have enough money for a PDP-11 so they bought an Interdata 7/32 instead.
The Interdata didn’t run Unix, of course, so the plans for a Unix system were put on hold. Around that time, Richard Miller joined the department and was looking for a programming challenge. Reinfelds and Miller decided that porting Unix would be just the thing so Miller started work on the first Unix port. He started by recoding the C compiler’s code generator to output Interdata assembler code. That was difficult because the University of Wollongong had no PDP-11 and the University of New South Wales had no Interdata. A further complication was that there were funds for at most three trips to UNSW.
I’ll let you read Reinfelds’ story (it’s short) to see how it all worked out. It’s a tribute to Miller and Unix that a port was possible at all let alone so easily. Definitely worth reading.
Footnotes:
Of Lions Book fame.