31 Dec
2018
31 Dec
'18
3:43 a.m.
The primary difference between the 11/40 class and 11/45 class is separate I/D space which
I sometimes refer to as the 17th address bit because it allows you a full 64k of data
space as well as a 64k of instructions space.
After you are booted, a 45 class machine will run 40 class binaries unchanged. 40 class
machines can not run a.outs that are seperate I/D
You’ll probably want to configure a kernel for the 45 class machine. Look at the
differences in the *.s files in the kernel. IIRC there is a different file for 40 class
and 45 class systems
That said if you running the simh I would recommend going all the way to an 11/70
configuration because you can set it up for 4M of main memory.
Clem
Sent from my PDP-7 Running UNIX V0 expect things to be almost but not quite.
On Dec 30, 2018, at 9:25 PM, Will Senn
<will.senn(a)gmail.com> wrote:
Dear Unix Enthusiasts,
We are seriously considering upgrading our PDP 11/40 clone (SIMH), to a PDP 11/45
(preferably another SIMH) for our Unix v6 installation. Our CEO was traveling and met a
techie in first class (seriously, first class?) who told him that we needed one. I thought
I had better ask some folks who have gone before about it before we jumped on the
bandwagon. By way of background, Our install is pretty small with a few rk’s and 256K of
ram along with a few standard peripherals, and some stuff our oldtimers refuse to part
with (papertape, card punch, etc). It has fairly low utilization - a developer logs in and
writes code every few days and the oldtimers hunt the wumpus and play this weird Brit game
about cows. It could be considered a casual development and test environment and an
occasional gaming console.
Here is what I would like to know that I think y’all might be particularly equipped to
answer:
1. Are there any v6 specific concerns about upgrading?
2. Why should we consider taking the leap to the 11/45? Everything seems to work fine
now.
3. If we jump in and do the upgrade, how can we immediately recognize what has changed in
the environment? I.e what are some things that we can now do that we couldn’t do before?
4. If we just insert our current diskpacks into the new system, will it just boot and
work? Or what do we need to before/after booting to prepare/respond to the new system?
5. Is 256K enough memory or what configuration do y’all recommend?
6. Is there anything else we need to know about?
Regards,
Will
Sent from my iPhone