[TUHS] running BSD 2.11 on my PDP 11/70 emulator

[Kenneth Goodwin]

It is the BSD kernel or the emulator setup I question as to being correct.
The clues being
An almost 4 mb available memory coupled to a roughly 300 kb user space. The
300kb doesn't make sense at all from the limits of the split i/d memory
layout. It's roughly 10% of available.
It's inferring that the kernel itself is being configured as a 3.5 mb
runtime image.
Almost as if dynamic kernel level  buffers are being over allocated by a
configuration parameter or a miscalculation.

The other clue being the dump of the printf style format strings from the
data portion of the involved user space program images as it boots. That's
the sign of a wrong address potentially being used. An address fault
causing an abend happening to multiple binaries being launched for example

These are the anomalies I see.

The solution requires someone very familiar with the bsd 2.11 boot up
sequence and the underlying executables involved. I am a V6, v7. System V
head.

Unfortunately Mr. Jolitz is no longer with us.

As I recall, the bsd folks were back porting some of the features of the
Vax virtual version of the bsd kernel as appropriate to the pdp version. I
dont recall what was involved in that effort.  The source code environment
for 2.11 would help.

I also don't know if those failure messages are coming from the bsd image
handling address faults etc. or the actual emulator underneath detecting
problems in the binary as it executes it.

So the questions to be answered are

1. Why is the user memory only 10% of the available?

2. What is dumping and the "why of it" the text strings in the data space
portion of the program image?

I don't the answer. But it all strikes me as odd.

On Mon, Apr 7, 2025, 12:15 PM Ron Natalie <ron at ronnatalie.com> wrote:

> The 45 also has split I/D.    The 11/ 70 is designed that if you can put a
> kernel that is cognizant only of the lower numbers in the line, it will
> still work.
>
>
> ------ Original Message ------
> From "Kenneth Goodwin" <kennethgoodwin56 at gmail.com>
> To "Folkert van Heusden" <folkert at vanheusden.com>
> Cc "The Eunuchs Hysterical Society" <tuhs at tuhs.org>
> Date 4/7/2025 8:02:01 AM
> Subject [TUHS] Re: running BSD 2.11 on my PDP 11/70 emulator
>
> To me it looks like a memory issue of some sort. Setup of the MMU etc.
>
> 1. Your user memory is less than 10% of "available memory" which should be
> the amount left after the kernel loads and allocates dynamic  buffers. User
> memory should be alot closer to available number. Unless it is referring to
> limits of mmu per process and not total available for all user level
> programs.
>
> 2. The bulk of the text dump seems to just be random initialized data
> dumped from Ram.
> Aka - Printf() format strings.  Indicates that the wrong address in memory
> is potentially being accessed.
>
> Perhaps the pdp11 emulator configuration does not have a correct mmu for
> your image file.
>
> For example,  you are running the 11/70 emulation and the binary image you
> are running is actually compiled for a pdp 11/45.
>
> The 11/70 has an mmu supporting split instruction and data spaces. 64k
> instruction,  64k data. But the kernel you are using was compiled to run on
> a non split I And D version of the pdp11 supporting only 64kb of combined
> user and data.
>
> On Mon, Apr 7, 2025, 3:30 AM Folkert van Heusden <folkert at vanheusden.com>
> wrote:
>
>> Hi,
>>
>> For fun I'm developing a PDP 11/70 emulator. It runs on everything from
>> ESP32 microcontrollers up to linux, windows, etc
>> https://vanheusden.com/emulation/PDP-11/kek/
>> Currently it can run UNIX 7 in multi user mode.
>> Of course I would like it to run BSD 2.11 as well (because of the
>> networking support). It boots, but after outputting the memory amounts
>> it produces a lot of garbage. It does eventually complete booting and
>> then allows you to log in.
>> I wonder if you sees this:
>> https://paste.nurd.space/mqIDB_0SjoDoJoasOGkiNQ_NjpRsCufAJCnKTA7ZxUI
>> (text) or
>>
>> https://imgpaste.nurd.space/pics/437bcf0d149a017168cbbf2def8560917a037a3935c5c3aa1fbea2f7e43b485a.png
>> (image), does this ring a bell to anyone? I verified with simh that the
>> disk-image should work.
>>
>>
>> regards
>>
>> --
>> www.vanheusden.com
>>
>
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