The 9000 Series 500 is very different from later 9000s. I don’t think there more than one speed of CPU, although there was an early and later CPU with the later CPU having a floating-point unit onboard. What you get out of a 9000 Series 550 over a Series 520 (aka 9020) is mostly more I/O slots, as I recall the 9020 had a short I/O cage. But I think the processor cage is the same size and can host about the same sets of cards.
The CPU is a 32-bit stack machine, very like a wide classic-3000, and there can be up to three CPUs in a system. There is an IOP that front-ends a CIO-type I/O bus (same bus and some of the same peripheral cards used in early PA-RISC systems) and I think you can have two IOPs in a system. HP-UX for them is very interesting from a historical perspective in that the Unix kernel is a complete rewrite. It is hosted on top of HP’s “SUN OS” operating system (there is also a single-user BASIC system for the 9020, also hosted on SUN OS) and written in HP’s MODCAL language. The filesystem is HP’s Structured Directory Format. The userland is largely made up of ports from AT&T System III (and later System V) and 4BSD. So when it is running HP-UX it looks like Unix, with some exceptions. One is that if you open and read a directory from your C program there are no entries for . (current) or .. (parent) directories; these are done in SDF’s directory entry and not present in the actual Unix directory. Yes, ls -a shows them: it is faking them to make it look more like Unix! -Frank McConnell (supported Wollongong’s TCP/IP on these) On May 17, 2018, at 13:48, Ed Sharpe wrote: > > actually we are lacking 9000 gear for smecc. where is it located? we are in > AZ... > HP Computer Museum overseas is awesome... The site has saved us mauna time > with the excellent documents there. > > ed# > > Sent from AOL Mobile Mail > > On Thursday, May 17, 2018 David Collins via cctalk <firstname.lastname@example.org> > wrote: > I agree with Al. Chas approached the HP Computer Museum on this and as much > as they would be great to add to the collection, the shipping costs to > Australia and the fact that the museum is more in a consolidation mode than > acquisition meant we weren’t able to take them in. > > Hopefully someone close by to him would like to have these units! > > David Collins > > Sent from my iPad > >> On 18 May 2018, at 1:35 am, Al Kossow via cctalk <email@example.com> >> wrote: >> >> Series 500 machines are quite rare. Someone should save these. >> >>> On 5/16/18 10:00 PM, Lawrence Wilkinson via cctalk wrote: >>> >>> I own several HP 9020 work stations along with peripheral gear associated >>> with that series. >> >>