On 04/18/2019 10:56 AM, Noel Chiappa via cctalk wrote: > > From: W2HX > > > i have a few CPUs available to me, a 11/23+, an 11/73 and I also have > > available to me an 11/83 > > I would like to try to run as many different OS's as may interest me, > > including some unixes as possible (bsd...etc). > > Early Unixes in general will run on those machines - but not straight off the > tape (since they didn't exist then, and have quirks which aren't supported). > > I've brought up V6 on a /23 (which must have the KTF11-A MMU chip); here: > > http://gunkies.org/wiki/Running_UNIX_V6_on_an_-11/23 > > are instructions on exactly what (minor) changes need to be made for it to > run. > > The /73 and /83 should be subsets of that, although you'll want to start with > m45.s, because those machines support the split-I-D MMU of the -11/45. (A /23 > Unix binary would boot/run on them, if you don't feel like doing a special one > for them.) I haven't yet tried V6 on them; if you want me to, and do a > writeup, let me know. The /73 and /83 have LTC registers, so on those you > won't need the LTC hack. > > Also, you may know this already, but if not, note that the /83 is a PMI: > > http://gunkies.org/wiki/Private_Memory_Interconnect > > machine, and _MUST_ be plugged into a Q/CD backplane _only_; plugging into > a standard Q/Q backplane will _damage_ it. > > > > would I see any improvement in performance with the FPU compared to > > without it? Or does the application running need to be something like > > fortran to see any perceivable difference? > > As someone noted, the /73 and /83 implement thefloating point instructions in > microcode, so the code can't tell if the optional FPJ11 FP hardware > accelerator is plugged in or not. In general, only on applications (the > language is not relevant) which are heavy users of FP would you see any > difference. > > On the /23, with no KEF11-A FPU chip plugged in, there are no floating point > instructions at all, so any application which tries to use them will blow out > (although under V6 there's an emulator); see here: > > http://gunkies.org/wiki/Setting_up_UNIX_-_Sixth_Edition > > and search for 'floating point' to see discussion of it). > > > > From: Ethan Dicks > > > v5, v6, and v7 UNIX shouldn't require any sort of math hardware. > > Don't know v5/v7 in detail, but AFAIK that's accurate. V6 can _support_ > FP hardware on machines which have it, and is otherwised prepared to > emulate those instructions (see above). > > > From: Paul Koning > > > I think that was typically called "EAE" (extended arithmetic element), > > a Unibus peripheral that implemented integer mul/div ... It only > > applies to 11/20 and 11/05 since all the other machines have the > > relevant instructions built into the CPU. > > Also the -11/04 and -11/03 were both missing the EIS; the former could use > the EAE, for the latter the optional KEV11-A or KEV11-B microcode chips both > provide it. > > > From: Josh Dersch > > > The EAE was also an option on the 11/40. > > Technically, on any UNIBUS machine; on the /40, the EIS (added instructions, > not the device model of the EAE) was available via an optional board in > the CPU. > > Noel All,
Experience is that an 11/23 or 23+ will run V6 as mine does. REason it does is V6 does not require I&D support The usual issue is not FPU for Unix as questioned but if there is a need for I&D spaces. The 11/23 (f11 chipset) does not support that but the J11 (11/73 and 11/83) do support that. I have a 11/73 so I could run BSD and a few others commonly found that require I&D support. There may be other versions that place less of a burden on requiring I&D. However I've not encountered a need for FPU connected to OS. Also the assumption for many unix is MMU support but not all DEC OS have that requirement. Allison
