RootPrompt.org: OMU – “One Man Unix”

[ Thanks to Noel
for this link. ]

“In the late 1970s and early 1980s (the good old days of “hobby
computing”) before the IBM PC and its clones took over the world,
various microprocessor based kits appeared on the hobbyist market.
…unhappy with the straitjacketed architectures and joke operating
systems of the 1st generation home computers, I yearned for…
something more like a Unix clone at home. I was used to V7 Unix on
the PDP-11 at university and wasn’t keen to step backwards 10 years
to the technology of CP/M and BASIC programming. I wasn’t to
know that eight years later a guy called Linus Torvalds was going
to think the same thoughts and do much the same things. The big
difference was that he was in the right place and the right time
and had internet connectivity
– I didn’t have any of these

“After going through the usual hard work of writing a BIOS
complete with an S-records downloader, I was in a position to write
myself an operating system. Preliminary work on OMU started in late
1983. My earliest surviving printouts of the sources on yellowed,
faded lineprinter paper show that the bulk of the work on OMU dates
from March/April/May 1984.”

“The lack of an MMU and the small amount of RAM available meant
that I decided against trying to implement true multitasking.
Instead (like DOS as it happens) I came up with a scheme whereby a
process could launch another process, but would have to wait for it
to complete. Clunky, but it worked OK.”