1 Jun
2007
1 Jun
'07
5:33 p.m.
On 6/1/07, Mr Ian Primus <ian_primus at yahoo.com> wrote:
Well, the consensus is that I really don't need
that
RDM board in order to boot the Vax.
I concur.
So, I'm going to
go ahead and see if I can boot something (anything) on
this machine. I figure I'll start with NetBSD, since
it's free and easy to get.
Sure.
I have no disk controller. But I do have an M7454
TU80
controller. Will this controller work with a normal
pertec tape drive, like a Cipher?
Perhaps. I think I've gone the other way (hung a TU80 off of a 3rd
party Qbus tape controller like a TC131), so I don't _think_ there's
anything strange.
Unfortunately, I don't think you'll see too much in the way of
bootable 9-track tapes for the VAX. PDP-11s of the right era
routinely installed from a bootable magtape, but not VAXen.
Instead, they have some console medium (11/780 == RX01, 11/750 and
11/730 == TU58, VAX8600 == RL02, VAX 8200 == RX50...) The 11/750 is
a bit off for the oldest types of VAXen in that it doesn't have a
dedicated boot processor, but in other ways, it's typical of the
11/7xx line.
Since I have SCSI nine track drives, I can write a
tape from my PC (linux box) and then I can move the
tape over to the Vax. (hopefully). Once there, how do
I boot - is the boot device switch controlled by the
RDM, or something else?
There's a switch on the front of your VAX with positions from A-D.
Each position corresponds to a bipolar PROM socket on one of the CPU
boards. Typically, your preferred boot ROM goes into A, and the one
for TU58 goes into D. We had a DR boot (for our SI9900), a DU boot
(UDA50) and a DD(?) boot for TU58. I don't recall there being a TS or
TM boot for the 11/750, but you could dig around. I suppose you could
enter any random bootstrap into Console ODT, but we never did that.
The usual technique for booting a blank 11/750 with some OS was to
start with the install kit, a stack of TU58s and magtapes. You boot
the first TU58, then follow the directions to insert the remaining
ones as required, to get into some standalone restore utility. At
some point, it's all loaded, then activity turns to siphoning whatever
tape drive onto whatever disk drive, then rebooting the disk to
complete the install. The software is all different, but the
technique was the same for Ultrix or VMS, back in the day. It's
entirely possible that BSD has a different technique, but since we
never had a boot ROM for tape drives, I don't think that's how we
installed 4.0BSD when we were running it on our 11/750 (I personally
only ever installed VMS and Ultrix).
If you can't get a stack of TU58s with the right restore application
on them, your next best bet is likely to be some flavor of TU58
emulator and images files from a modern machine. I don't think
there's an easy way away from that except to pre-load a disk image
external to the 11/750 then boot the 11/750 "in the middle" of the
established install procedure.
-ethan