[Simh] Install VAX/VMS 4.4 on a simulated VAX-11/780

[Henk van de Kamer]

Clem Cole schreef op 25-3-2018 om 23:23:
>> A small suggestion...   while you can probably get the 780 to 
>> recognize and support a TU58, booting from it may be difficult (I 
>> did not find it mentioned in any SDP or other doc).

In another post I gave a link which suggested that it could be present.

>> The 780 family has a dedicated PDP-11 with RX floppy drives that 
>> runs as the 'front end' for it and boots it. The PDP-11 run an 
>> small OS RSX-11/S (I think - but man those bit in my brain are long
>> lost) and can reach in the SMI to load the OS image into memory
>> from the disk and then points the system at it.

I searched what the TU58 exactly was and found [1]. They say it could be
used to bootstrap the RT-11 [2] operating system on a PDP-11. That seems
to be the one :-)

>> The 750 and 730 have boot roms for he VAX itself that know how to 
>> talk to the peripherals such as the TU58 .

Thanks for that clarification. Slowly I see how things fitted together.
The main problem for me is not knowing what all the letters are standing
for.

>> IIRC, the TU58 controller is sitting on the UBA and I really don't
>>  think the code in the PDP-11 knows how to get to them.   The path
>>  to make that all would be a tad convoluted and I suspect no one 
>> bothered to write for the TU58  it back in the day because 
>> everything for the VAX was based on either the RX floppies, 9-track
>> tape or the disk itself.
>> 
>> That said, in theory, a 750 should be able to create a disk image 
>> that contains an OS that could be booted on a 750 and a 780. So...
>> 
>> 
>> What you might consider, is setting simh4.x up as a 750 and read 
>> those tapes, set up the system and create RP06/07 or RM05/06 etc. 
>> disk images.   Then reconfigure the simulator as a 780, and attach 
>> that disk image.  Then use the standard 780 boot via the RX 
>> floppies and the PDP-11, you should be all set.

In another post the same was suggested. However I only found three TU58
tape files with the standalone backup 4.0. But:

Wilm Boerhout schreef op 26-3-2018 om 11:35:

> Well, I followed this thread and just tried a part of it (booting 
> standalone Backup on  a 750 from TU58).
> 
> It started OK, but failed unexpectedly reading/processing the second
>  S/A backup TU58 image)
> 
> See below for details. my comments are between [ ]

The output is all garbled up, but I think some of it is:

**** VERSION ****
sim> show version
   VAX 11/750 simulator V4.0-0
[snip]
**** CONFIG ****
...
att TD0 /tu58/VAX750-CON01.TAP
[note: this is a console tape image from 
http://iamvirtual.ca/VAX11/VAX-11-software.html]
[snip]


That are the same tapes I found. I checked the devices on the vax780 and 
don't have a TD device. There are emulators which outputs to RS232 but I 
don't now if that can be used on the VAX-11/780.

If not, then the only way to install VMS 4.4 is to use a prepared disk 
from someone else. If I understand correctly that can then be used to 
build RX01 floppy images. Those by the way I could not found in a quick 
search. However this is not a very clean hack. For me the "correct" way 
is to use images form original tapes, floppies or whatever. And it seems 
that that can't be done anymore?

Before someone mentions OpenVMS. Yes that is original software. However 
that is from a later point in time. So to me that also doesn't feel 
right. I know, I'm to picky but that is what a challenge is all about :)






[1] https://en.wikipedia.org/wiki/DECtape#DECtape_II
[2] https://en.wikipedia.org/wiki/RT-11

-- 

Henk van de Kamer
http://www.vandekamer.com/
http://www.hetlab.tk/