[TUHS] Mach'86

Jason Stevens jsteve at superglobalmegacorp.com
Tue Jul 16 19:32:56 AEST 2019

For anyone that is interested, there is 2 files on Kirk’s DVD that don’t appear on the CD’s


The smaller mach.86-accent is a few months newer than the other, and is strictly the kernel.  mach.86 contains 
stuff like the libraries for mach, bindings for pascal, along with an updated libc, and various binaries to run under
4.3BSD.  It appears that the Mach project at that time was pretty much in step with the CSRG release.

Speaking of pascal, the early version of MIG is actually written in pascal.  There is quite a #ifdef ACCENT stuff in the code
As well.  So the bindings are more than something superficial.

I had a major issue trying to use RA81 disks on SIMH, although switching to RP06’s seemed to have made things a 
little more stable, the larger issue seems to have been the async I/O code, and disabling that increased stability
and reduced disk corruption greatly.

Setting up the build involved copying files from the ‘cs’ directory to their respective homes, along with the ‘mach/bin/m*’
commands to the /bin directory.  Configuring the kernel is very much like a standard BSD kernel config, however the directory
needs to exist beforehand, and instead of the in path config command run the config command in the local directory.

I have been able to self host a kernel, and build a good portion of world before I realized that the I/O was probably what I was
Fighting and went back and restored the 4.3 tape back onto the HP’s and just re-built the kernel to verify it works.  For those
Wanting the command for SIMH it’s simply ‘set noasync’.  The XU adapter worked out of the box with a simple:

set xu ena
att xu nat:tcp=42323:

Which allowed me to telnet into the VAX, making things much easier than dealing with the console.

While this kernel does have mentions of multi processor support I haven’t quite figured out what models (if any) are supported
On the VAX, and if SIMH emulates them.  While http://www.oboguev.net/vax_mp/ has a very interesting looking multiprocessor VAX
Emulation it’s a fictional model based on the microvax, which I’m pretty sure 4.3BSD/Mach’86 is far too old for.

And for those who like the gratuitious dmesg, this is a self hosted Mach build

loading hp(0,0)boot
: hp(0,0)vmunix
393480+61408+138472 start 0x1fa5
Vax boot: memory from 0x92000 to 0x800000
Kernel virtual space from 0x80000000 to 0x82000000.
Mach/4.3/2/1 #1: compiled in /usr/mk/MACH on wb2.cs.cmu.edu at Mon Oct 20 12:54:42 1986
physical memory = 8.00 megabytes.
available memory = 5.86 megabytes.
using 408 buffers containing 0.79 megabytes of memory
VAX 11/780, serial#1234(0), hardware ECO level=7(0)
mcr0 at tr1
mcr1 at tr2
uba0 at tr3
zs0 at uba0 csr 172520 vec 224, ipl 15
ts0 at zs0 slave 0
dz0 at uba0 csr 160100 vec 300, ipl 15
de0 at uba0 csr 174510 vec 120, ipl 15
de0: hardware address 08:00:2b:0d:d1:48
mba0 at tr8
hp0 at mba0 drive 0
hp1 at mba0 drive 1
hp2 at mba0 drive 2
hp3 at mba0 drive 7
Changing root device to hp0a

I uploaded my SIMH config, along with the RP06 disk images here:  https://sourceforge.net/projects/bsd42/files/4BSD%20under%20Windows/v0.4/Mach86.zip/download
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