At the risk of this drifting, it probably should move over to the COFF mailing list, which I have CC'ed. I'll do this one last one here so people not yet on COFF that want to follow up can see it.
It was bizarre and ugly. The only thing that made it anywhere
near usable were the Software Tools.
Amen... (more in a minute)
There's a reason Prime died pretty quickly once Unix started to
spread. The architecture also was strange; the characters used
mark parity (8th bit always on).
Yeah, it was an interesting box. Fast and cost-effective for its time and an excellent Fortran system which why they did as well as they did.
My 2 cents.
Arnold
You probably know this but you folks had a huge influence on the Pr1mates. So much so when Bill P, Paul L, and Michael S. left Pr1me to create Apollo, the used your version of the SWT as their first command system for Aegis (a.k.a. DOMAIN OS). They did not quite get it that they needed a real UNIX, so they roped tjt and myself from Masscomp went we all formed Belmont (a.k.a. Stellar in a later renaming). But they did recognize it was useful and people wanted to use that style of interface, not something dreamed up specific to that machine.
I remember trying to explain to Bill the difference - he's a vision guy, but primarily a hardware type, although one of the most amazing people I have ever known. IMO: Leach never really understood the Unix ideas of being simple (which is one of the reasons why Windows has that forsaken registry sin from Aegis, he brought it with him from Apollo to MSFT). I used to argue with him about it in the 1980s (he hated/thought ASCII text files were terrible and he should control everything in some framework or privileged API).