13

I'm curious if anyone is aware of actual uses of Unix on the Heathkit H11? I don't see any technical reason a memory-expanded H11 couldn't run Unix, but can't find any examples of it doing so.

7
  • 3
    Plausible. The H11 is an LSI-11/02 with max 32 kW of memory, and Unix "V6 will run on an LSI-11/02 with 28KW of memory." mail-archive.com/[email protected]/msg44100.html Oct 16, 2019 at 20:16
  • Nice question. Can't provide an Answer. Still, AFAICT, it should work. The H11 was basically a PDP 11/40, while the H11A is the equivalent of a 11/02, and could use any Q-Bus interface, including disks. Heath themself supplied an RX01 alike floppy and a RT11 version. So loading (some) Unix might work quite well - given a disk controller (Q-Bus SCSI or alike) is added.
    – Raffzahn
    Oct 16, 2019 at 20:16
  • 2
    An LSI-11 has an 11/40-ish instruction set but it doesn't have an MMU, so it's a single-mode single-space processor. That limits the operating systems you might run. From dusty memory cells, also, the PS is not accessible through the IO page (like normal -11 CPUs), but only via a new instruction, so it's likely not even binary compatible with unmapped operating systems.
    – dave
    Oct 17, 2019 at 0:38
  • 5
    @ralfzahn - careful with that "11/02". Generally speaking, "11/xx" means "PDP-11/xx", and there's no such thing as a PDP-11/02. There's also an "LSI-11", which is the microprocessor and/or the CPU module used in the PDP-11/03, and an LSI-11/2, no zero, which is its replacement (same microprocessor, different CPU module). Ain't DEC nomenclature grand? As far as I can tell from the 'net, the H11 was based on the LSI-11 board, and the H11A was based on the LSI-11/2 board. They're both 16-bit bus devices.
    – dave
    Oct 17, 2019 at 1:44
  • 1
    In the early (V6 days) there were a couple of mini versions of V6 that ran on an MMUless 28Kw system. Hans Lycklama's mini-unx could run on the minimal 11s but you'd still have needed a disk subsystem that didn't suck. I suspect that is actually the bigger issue - a 256K floppy does not cut it.
    – Alan Cox
    Feb 23, 2020 at 0:13

0

You must log in to answer this question.

Browse other questions tagged .