[TUHS] Porting 2.11 BSD

Nick Downing downing.nick at gmail.com
Mon Nov 23 10:56:42 AEST 2015

What I would do personally is:
1. Run in an emulator such as the ones linked above, it will be heaps
easier than the bare hardware. Need not emulate your particular machine.
Preferably would emulate your Z800x CPU but even that isn't 100% essential.
2. Get yourself a 2.11bsd filesystem, best way might be install or download
2.11bsd for PDP-11 and run in simh. Hopefully the simulated disk is in raw
form so it can be moved between simh and your emulator, otherwise you could
modify one of the emulators or convert the file somehow.
3. Figure out a way of copying between your real disk and your simulated
disk. For example run an sshd under simh and "scp" to your disk. Or mount
your file as a tape and "dd" it over to your disk with correct name. Or
whatever, there could be existing utilities that can do this. (Kind of like
msdosutils on linux has a userspace implementation of vfat and can do
simple things to vfat formatted floppies or disk images).
4. Figure out how the bootstrap works and translate it to Z800x assembly.
In essence the boot sector will load the next 16 or so sectors into memory
and jump to it. Those 16 sectors contain a cutdown version of a 2.11bsd
filesystem mounted rdonly, enough to read superblock, locate inode table,
maybe locate /boot/kernel and then load and jump to it. I can send some
examples in Z80 code for my project. Or I can take a look in 2.11bsd and
tell you how this works.
5. You now have a cross assembler and linker and a development system. Get
C working too. Compile the kernel with as many things as possible disabled
-- no disk, network, etc. Find a way for dprintf() or similar to work --
such as polled output to a serial port, or even just defining an unused
Z8001 opcode to putchar() whatever is in R1. No need for any finesse here.
6. In the first line of the kernel startup put a dprintf of "hello world".
Copy resulting kernel to /boot/kernel or whatever it is supposed to be
called. Put similar diagnostics in your bootstrap. Run and debug until your
messages come out. Then gradually step through the kernel initialization
and main loop fixing things as you go. Eventually add more subsystems.

On 22/11/2015 1:14 PM, "William Pechter" <pechter at gmail.com> wrote:

> Oliver Lehmann wrote:
>> William Pechter <pechter at gmail.com> wrote:
>> I found this for a Z8000 System III box. It was an East German dual cpu
>>> Z80/Z8001 clone box running SysIII -- perhaps this may be of some help as a
>>> comparison.
>> And I also redid (disassembled objects, translated it back to C) nearly
>> all Kernel sources of the SYSIII (only lock.c is missing with file
>> locking features - I only disassembled it)
>> https://github.com/OlliL/P8000/tree/master/WEGA/src/uts
>> Emulator
>>> http://www.knothusa.net/Home.php
>> Yes... he built the Emulator based on MAME back in 2008 with quite
>> some info from me - he used to work on a P8000 back in the 90s so
>> he felt for it building the Emulator.... ;)
>> More P8000 info
>>> http://www.pofo.de/P8000/
>> Z8000 docs
>>> http://www.pofo.de/P8000/  (there's some Zilog System 8000 Z8000 Zeus
>>> info here as well.
>> Cool... you found my page ;)
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> Nice site... I worked for DEC back in the 80's and I ended up installing
> Exxon Office Systems'  Vaxes which
> they used for software development for the Zeus systems.  Some employees
> were from the Berkeley area
> and New Jersey, even Princeton, seemed to be culture shock.
> The computer room was directly under the flight path to the little
> Princeton Airport and the rented building
> wasn't really designed for those machines.  The place was small offices
> for insurance sales, accounting,
> lawyers and such.   They later moved over to a new building on the RT 1
> corridor which had a real computer room after they had all the electricity
> put in for the 11/780.
> They moved from California to Princeton, New Jersey back around '81 or so
> and were gone shortly
> when Exxon closed them down in '84.
> I think they were the first Ultrix32 box I saw in my lifetime... which was
> much more AT&T focused working
> for DEC in New Jersey.  By 92 or so I was doing SunOS 4.1.3 at work and
> FreeBSD/NetBSD at home.
> I never could figure out how AT&T kept the miserable self-destructive Unix
> Filesystem alive with it's 13 character filename limit and no symbolic
> links.  SysVR4 finally showed some promise, and I even
> thought they had a winner with their object-oriented management tools to
> manage getty's and printers and such.
> FACE, the SVR4 character terminal graphic utilities were not too bad. You
> could finally run the whole system without vi-ing configurations -- kind of
> like a pre-SUSE  Yast that used the button labels on function keys.
> Perkin-Elmer/Concurrent had a similar thing in Xelos (SVR2) on their
> block-mode capable 1251 and 6312
> terminals...  That was the thing in the 80's -- menu or function button
> Unix sysadmin screens.
> AT&T killed their future OEM's by allowing the OSF/USL split to happen
> over their Sun investment
> and promise that Sun would get the new Unix before everyone else. The Unix
> wars made sure there
> wouldn't be one binary/source compatible version of Unix across all
> hardware platforms.
> When I started to work with Solaris2 I was amazed as to how different it
> seemed than straight SVR4 and
> I helped write Pyramid's training for their OS/x SVR4 MIPS R3000 product.
> Had AT&T been more willing to supply the code equally and get out of the
> way you wouldn't have had
> the waste of the NCR purchase later after the less than stellar 3b and 3b2
> sales of the late 80's.
> To bring this back to the Z8000 ZEUS and Zilog:
> Pyramid was an OEM for AT&T and AT&T was to sell Pyramid boxes to the US
> Government to replace
> the Z8000 Zilog Zeus machines which were used by the IRS.  I think this
> all fell apart after the
> NCR purchase.  My job kind of went with it as Pyramid went through a
> downward sales spiral
> as AT&T stopped buying MIServers and the MIPS MIServer-S line (R3000 SVR4)
> multicpu boxes.
> Bill
> --
> Digital had it then.  Don't you wish you could buy it now!
> pechter-at-gmail.com  http://xkcd.com/705/
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