Peter Allan petermallan at
Tue Apr 30 14:39:59 CDT 2019

On 4/28/19 3:55 PM, Ray Jewhurst via cctalk wrote:
> I am new to the list and would like to introduce myself. I
> am a computer history buff who especially likes DEC machines.

> I unfortunately don't own any hardware but I use Simh on a daily
> basis. I would like to start off with a question. I see that Bitsavers
> has a copy of VMS 1.5 and wanted to know if anyone got it working
> with the Vax 780 simulator?

> I hope to learn a lot from this group.

Hi Ray, about 18 months ago, I did indeed install VMS 1.5 on a simulated
(with simh) VAX-11/780. It was not particularly difficult, but it did take
a bit more effort than I expected. Here is what I did and the problems that
I came across. I am typing this from memory, so I might have mis-remembered
the odd fact.

The instructions tell you to create a bootable disk from tape using the DSC
utility. However, DSC was something that ran in PDP-11 emulation mode on a
VAX and was discontinued early enough in the evolution of VMS that it was
not present on any of my simulated systems (VMS 4.x, 5.x and 7.3). I needed
to build a VMS 3.0 system in order to complete copying the VMS 1.5 tape to
disk. If you have a simulated PDP-11 system, you might be able to use that

Building the VMS 3.0 system gave me another problem in that I tried using a
simulated TE16 (Massbus) tape drive to read the VMS 3.0 installation tape.
This should have been fine, but actually I uncovered a bug in simh. Bob
Supnik fixed the bug, but you do need to use an up to date version of simh
to get the bug fix. If you need to use an old version of simh for some
reason, then use a TS (Unibus) tape drive and all should be well.

VMS 1.5 is primitive compared with later versions, but does have historical
interest. Do let me know if you want any further information about my
adventures with VMS 1.5.


Peter Allan

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