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* [TUHS] Unix on an 11/23 (Was: Work I've done with a PDP-11 simulator)
@ 2014-05-21 19:39 Noel Chiappa
  0 siblings, 0 replies; 9+ messages in thread
From: Noel Chiappa @ 2014-05-21 19:39 UTC (permalink / raw)


    > From: asbesto <asbesto at freaknet.org>

    > We have about 40 disks, with RT-11 on them

Ah. You should definitely try Unix - a much more pleasant computing/etc
environment!

Although without a video editor... although I hope to have one available
'soon', from the MIT V6+ system (I think I have found some backup tapes from
it).

    > This PDP-11/34 was used for a medical CAT equipment

As, so it probably has the floating point, then. If so, you should be able to
use the Shoppa V6 Unix disk as it is, then - that has a Unix on it which will
work on an 11/23 (which don't have the switch register that V6 normally
requires).

But if not, let me know, and I can provide a V6 Unix for it (I already have
the tweaked version running on a /23 in the simulator).

	Noel

PS: For those who downloaded the 'fixed' ctime.c (if anyone :-), it turns out
there was a bug in my fix - in some cases, one variable wasn't initialized
properly. There's a fixed one up there now.



^ permalink raw reply	[flat|nested] 9+ messages in thread
* [TUHS] Unix on an 11/23 (Was: Work I've done with a PDP-11 simulator)
@ 2014-05-20  2:19 Noel Chiappa
  2014-05-20 13:51 ` asbesto
  0 siblings, 1 reply; 9+ messages in thread
From: Noel Chiappa @ 2014-05-20  2:19 UTC (permalink / raw)


    > From: asbesto <asbesto at freaknet.org>

    > Just in these days we restored a PDP-11/23PLUS here at our Museum! :)
    > ...
    > CPU is working

That is good to hear! You all seem to have been very resourceful in making
the power supply for it!

    > and we're trying to boot from a RL02 unit :)

Is your RL02 drive and RLV11 controller all working? Here are some
interesting pages:

  http://www.retrocmp.com/pdp-11/pdp-1144/my-pdp-1144/rl02-disk-trouble
  http://www.retrocmp.com/pdp-11/pdp-1144/my-pdp-1144/more-on-rl01rl02

from someone in Germany about getting their RL11 and RL02 to work.

Also, when you say "boot from an RL02", what are you trying to boot? Do you
have an RL02 pack with a working system on it? If so, what kind - a Unix
of some sort, or some DEC operating system?


    > From: SPC <spedraja at gmail.com>

    > I'll keep a reference of this message and try it as soon as possible...

Speaking of getting Unix to run on an 11/23 with an RL02... I just realized
that the hard part of getting a Unix running, for you, will not be getting V6
to run on a machine without a switch register (which is actually pretty easy
- I have worked out a way to do it that involves changing one line in
param.h, and adding two lines of code to main.c).

The hard part is going getting the bits onto the disk! If all you have is an
RL02, you are going to have to load bits into the computer over a serial line.

WKT has done this for V7 Unix:

  http://www.tuhs.org/Archive/PDP-11/Tools/Tapes/Vtserver/

but V7 really wants a machine with split I/D (which the /23 does not have). I
guess V7 'sort of' works on a machine without I/D, but I'm not a V7 expert,
so I can't say for sure.

It would not be hard to do something similar to the VTServer thing for V6,
though. If you would like to go this way, let me know, I would be very
interested in helping with this.


Also, do you only have one working RL02 drive, or more than one? If you only
have one, you will not be able to do backups (unless you have something else
connected to the machine, e.g. some sort of tape drive, or something).

	Noel



^ permalink raw reply	[flat|nested] 9+ messages in thread
* [TUHS] Unix on an 11/23 (Was: Work I've done with a PDP-11 simulator)
@ 2014-05-15 20:56 Noel Chiappa
  2014-05-19 13:44 ` asbesto
  0 siblings, 1 reply; 9+ messages in thread
From: Noel Chiappa @ 2014-05-15 20:56 UTC (permalink / raw)


    > From: SPC <spedraja at gmail.com>

    > I'll keep a reference of this message and try it as soon as possible...

No rush! Take your time...


    > the disruptive fact (in terms of time) here is to put up-to-date both
    > the PDP-11/23-PLUS and RL02. 

My apologies, I just now noticed that you have an 11/23-PLUS (it is slightly
different from a plain 11/23).

I am not very familiar with the 11/23-PLUS (I never worked with one), but from
documentation I just dug out, it seems that they normally come with the MMU
chip, so we don't need to worry about that. However, the FPP is not standard,
so that is still an issue for bringing up Unix.

In fact, there are two different FPP options for the 11/23-PLUS (and,
actually, for the 11/23 as well): one is the KEF-11AA chip which goes on the
CPU card (on the 11/23-PLUS, in the middle large DIP holder), and the other is
something called the FPF-11 card, which is basically hardware floating point
(the KEF-11A is just microcode), for people who are doing serious number
crunching. It's a quad-size card which has a cable with a DIP header on the
end which plugs into the same DIP holder on the CPU card as the KEF-11A. They
look the same to software; one is just faster than the other.

Anyway, if you don't have either one, we'll have to produce a new Unix
load for you (not a big problem, if it is needed).

	Noel



^ permalink raw reply	[flat|nested] 9+ messages in thread
* [TUHS] Unix on an 11/23 (Was: Work I've done with a PDP-11 simulator)
@ 2014-05-15  0:41 Noel Chiappa
  2014-05-15  2:03 ` John Cowan
  2014-05-15  6:51 ` SPC
  0 siblings, 2 replies; 9+ messages in thread
From: Noel Chiappa @ 2014-05-15  0:41 UTC (permalink / raw)


    >> I got one PDP-11/23-PLUS without any kind of disk (by now, I got one
    >> RL12 board plus one RL02 drive pending of cleaning and arrangement)...
    >> I guess if could be possible to run V6 in this machine. There's any
    >> kind of adaptation of this Unix version (or whatever) to run under ?

    > IIRC the README page for that set of disk images indicates that in fact
    > they originally came off an 11/23, so they should run fine on yours.

So I was idly looking through main.c for the Shoppa Unix (because it printed
some unusual messages when it started, and I wanted to see that code), and I
noticed it had some fancy code for dealing with the clock, and that tickled a
very dim memory that LSI-11's had some unusual clock thing. So I decided I
had better check up on that...

I got out an LSI-11 manual, and it looked like the 23 should work, even for
the 'vanilla' V6 from the Bell distro. But I decided I had better check it to
be sure, so I fired up the simulator, mounted a Bell disk, set the cpu type
to '23', and booted 'rkunix'. Which promptly halted!

After a bit of digging, it turned out that the problem is that the 11/23
doesn't have a switch register! It hit a kernel NXM trying to touch it -
and then another trying to read it in the putchar() routine trying to do a
panic(), at which point it died a horrible death.

So I added a SR (you can create all sorts of bizarre hybrids like that with
Ersatz-11, like 11/40's with 11/45 type floating point :-), and then it
booted fine. The clock even worked!


So you will have to use the Shoppa disk to boot (but see below), or we'll
have to spin you a special vanilla V6 Unix that doesn't try to touch the SR -
that shouldn't be much work, I only found two place in the code that touch it.

I did try the Shoppa 'unix', and it booted fine on an 11/23.

Two things to check for, though: first, your 11/23 _has_ to have the MMU chip
(that's the large DIP package with one chip on it nearest the edge of the
card), so if yours looks like this:

  http://www.psych.usyd.edu.au/pdp-11/Images/23.jpeg

you're OK. Without the MMU chip, most variants of Unix will not run on the 23
(although there's something called MiniUnix, IIRC, which runs on an LSI-11,
which would probably run on a /23 without an MMU).


Here's the part that might be a problem: To run any of the Unixes on the
Shoppa disk, you also have to have the FPP chip too (that's the second large
DIP package with two chips on it - the image above does not include that
chip, so if yours looks like that, you have a minor problem, and I will have
to build you a Unix or something).

All of the Unixes on the Shoppa disk have to have the FPP, except one - and
that one wants an RX floppy as the root/swap device! The others will all
crash (I tried one, to make sure) if you try and boot them on an 11/23
without the FPP.

I could try patching the binary on the one that doesn't expect to use the FPP
to use the RL as the root, or either i) build you a vanilla V6 for a 23
(above), or ii) figure out how to build systems on the Shoppa disk, and build
you a Unix there which i) uses the RL as the root/swap, and ii) does not
expect to have the FPP.

But let's first find out exactly what you have...

	Noel



^ permalink raw reply	[flat|nested] 9+ messages in thread
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2014-05-21 19:39 [TUHS] Unix on an 11/23 (Was: Work I've done with a PDP-11 simulator) Noel Chiappa
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2014-05-20  2:19 Noel Chiappa
2014-05-20 13:51 ` asbesto
2014-05-15 20:56 Noel Chiappa
2014-05-19 13:44 ` asbesto
2014-05-15  0:41 Noel Chiappa
2014-05-15  2:03 ` John Cowan
2014-05-15  4:48   ` Warren Toomey
2014-05-15  6:51 ` SPC

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