7 Apr
2013
7 Apr
'13
5:49 a.m.
Ethan Dicks <ethan.dicks at gmail.com> wrote:
allison <ajp166 at verizon.net> wrote:
My fault, I should have been more specific and included: "in terms of
features/peripherals/board count". Also, I was thinking relative to all 11s, not just
QBUS.
What OS to use is yet another undecided question, I haven't even read up on the
options.
I could also just try out some bare metal programming at the ODT for a start.
Seconded :)
Arno
Was it indeed
usual to build such large configurations based on an 11/23 back then?
That was not a small configuration, but it wasn't uncommon.
[data points for system configurations from Ethan and Allison] Not at all uncommon. Usually the disk round out might
have left out the
RQDX or the RX02
but many in the day wanted to move from 8" to 5.25 for space and needed
one system to do both.
OK, some more enlightenment absorbed.
You will want RX50 or RX02 as those were and are
common media.
Either way a RX02 or RX50 was the common simple and
cheap storage
that offered portability.
Mass storage for my system is another area I need to spend more thought on, for now I was
planning to stay with the RL drives I got with the case.
RL packs were over 160$ new and didn't like to
be bounced. FYI drives like RL02 were nearly as expensive as the base
machine ($8-12K).
The drives are not the problem, I have those. I will need to check them out and get myself
some more packs though. On second thought, some kind of floppy might be nice, too, but
that is not a must now.
If pressed for more mass storage, I could always put my QBus SMD controller (and a CMD
Phoenix fixed/removable drive combination I was recently offered )to use with this
machine, although I had got those rather imagined using them with my VSII/GPX.
Its easier to find Dias on RX50 or RX02 though
I've seen them on TK50
but hated loading them form that (slow!).
I do have a TQK(mumble) board already (which was originally also intended for the VSII),
but no drive yet.
> TQK50, DEQNA and RQDX3 at least sound sound a bit
anachronistic
> to me, there surely must have been newer and more powerful
> processors out at the time those became available?
There were - you could get a MicroPDP-11 with a KDJ11,
and lots
of people did, but they cost more. I wouldn't have wanted to run
an RSX-11/M+ system on a KDF11, but I did see plenty of them on
KDJ11 processors (but even more on Unibus machines).
TK50 was tape DLT tape. DEQNA was ethernet, and RQDX3 was
MSCP floppy and hard disk controller.
CPU typically was 11/23+ or 11/73 later on for a price.
So the distinction between the rackmount and MicroPDP/VAX eras wasn't as sharp as I
imagined it.
I have such boards (ok, a DELQA in this case) in said VSII.
I think
I'll have a rather minimal system (KDF11-B, 512kW RAM,
quad SLU, RLV12 + one or drives) for now, not making my first
foray into pdp technology more complicated than necessary.
I would call that a mid-range Q-bus PDP-11 myself, not "minimal".
Among other characteristics, I personally think of Q22 as "not minimal".
You can do a lot with RT-11 in 18 bits of memory. The fact that it had 4MB of ram was uncommon as back
in the day that was
as costly as the base machine if not more.
I understand that memory was at a premium back then.
Out of interest, how common was core memory (H223 and similar) in QBUS systems?
Is BBU supported for the MOS memory options?
I would call
that a mid-range Q-bus PDP-11 myself, not "minimal".
(...)
Among other characteristics, I personally think of Q22 as "not minimal".
You can do a lot with RT-11 in 18 bits of memory.
Yes, you can even in 16bits. I also have a tiny system using M8186 in a
12 slot dual wide cage running 512KB ram (4 boards), MRV11 (boot),
DLV11J for serial IO, and TU58 for storage. It boots the TU and copies
it to VM: and reboots from there making for a small but very fast
RT-11 system. The OS only use the 28KW and the rest is a virtual
disk (ram disk) big enough to copy the whole base os and a few
useful apps. I think you meant 150MB for RQDXm for its upper limit.
For larger
there were large disks but that was uncommon for Qbus 11s.
RT11 could barely fill (the whole mess) a 20mb drie with much room
left over. For RSTS or RSX a 31mb (RD52) was enough and two
did the trick.
So with just 1-2 RL0x drives, I'm pretty much stuck with RT-11? I've read that it
has a lot in common with later DOS, so that might not even be a bad thing after all :)
larger systems often had mag tape either DLT (tk50)
or 9track for backup and sneakernet (off site or remote systems
before WAN).
No such stuff in sight alas, but ISTR there is some sort of emulator software that makes a
PC act as a serially-attached tape device?
When I was using the BA11N system I described, I owned
an RL01
because I couldn't afford an RL02.
FWIW, I was messing with this system just last month. It's still intact.
Nice to hear that. How problematic are the BA11-N power supplies, BTW?
The system I
still use is the tall (50") rack BA-11 CPU I used in my office
when I was in the Mill (ML03-6/B5) as a utility system for printing and
off line (non VAX work). Still fun to use and I even have a few
uVAX3100s running VMS for it to talk to.
Cool.