Method one: Distributed ready-to-run images
This one works out of the box: Download the zip file with three images from the link given in the mini-unix page, namely munixrks.zip.
Extract images, make a configuration file distrib.ini that contains
set cpu 11/20
set cpu 64k
attach rk0 mxrk05a.img
attach rk1 mxrk05b.img
attach rk2 mxrk05c.img
boot rk
Start the system, and you can mount them:
$ simh-pdp11 distrib.ini
PDP-11 simulator V3.9-0
Disabling CR
Disabling XQ
@rkmx
RESTRICTED RIGHTS
USE, DUPLICATION OR DISCLOSURE IS SUBJECT TO
RESTRICTIONS STATED IN YOUR CONTRACT WITH
WESTERN ELECTRIC COMPANY, INC.
;login: root
# /etc/mknod /dev/rk2 b 0 2
# mkdir /usr/source
# /etc/mount /dev/rk1 /usr/source
# /etc/mount /dev/rk2 /mnt
# ls -l /usr/source
total 36
drwxrwxr-x 2 bin 368 Jan 26 1976 as
drwxrwxr-x 2 bin 928 Aug 31 02:34 c
drwxrwxr-x 5 bin 128 May 13 1975 cref
drwxrwxr-x 11 bin 368 Sep 4 01:45 fort
drwxrwxr-x 2 bin 1248 Jan 27 1976 iolib
drwxrwxr-x 2 bin 320 Jan 27 1976 m6
drwxrwxr-x 2 bin 464 Sep 4 01:46 mdec
drwxrwxr-x 2 bin 288 Sep 3 23:35 rat
-rw-rw-r-- 1 bin 753 May 18 1975 run
drwxrwxr-x 2 bin 1696 Sep 4 04:41 s1
drwxrwxr-x 2 bin 1280 Sep 4 01:47 s2
drwxrwxr-x 2 bin 816 Jan 26 1976 s3
drwxrwxr-x 2 bin 2544 Jan 26 1976 s4
drwxrwxr-x 2 bin 1264 Jan 26 1976 s5
drwxrwxr-x 2 bin 800 Aug 31 00:28 s7
drwxrwxr-x 2 bin 384 Sep 4 03:38 salloc
drwxrwxr-x 2 bin 224 Aug 30 22:44 sno
drwxrwxrwx 3 hl 192 Sep 4 03:47 tmg
drwxrwxr-x 4 bin 80 May 13 1975 yacc
# ls -l /mnt
total 16
drwxrwxr-x 2 bin 48 Jun 26 1975 as
drwxrwxr-x 2 bin 80 Jun 26 1975 bc
drwxrwxr-x 2 bin 176 Jun 26 1975 beg
drwxrwxr-x 2 bin 240 Jun 26 1975 c
drwxrwxr-x 2 bin 464 Jun 26 1975 ctut
drwxrwxr-x 2 bin 176 Jun 26 1975 ed
drwxrwxr-x 2 bin 144 Jun 26 1975 hel
drwxrwxr-x 2 bin 48 Jun 26 1975 iolib
drwxrwxr-x 2 bin 48 Jun 26 1975 iosys
drwxrwxr-x 11 bin 192 Jun 26 1975 man
drwxrwxrwx 2 root 416 Dec 21 17:21 new
drwxrwxr-x 2 bin 48 Jun 26 1975 rat
drwxrwxr-x 2 bin 64 Jun 26 1975 secur
drwxrwxr-x 2 bin 96 Jul 17 1975 start
drwxrwxr-x 2 bin 192 Jun 26 1975 unix
drwxrwxr-x 2 bin 288 Jun 26 1975 yacc
However, as the mini-unix page remarks
The disk images may not be quite perfect.
the second method may give results closer to the original distribution.
Method two: Installing from tape
Follow the steps for stage1 and stage2.
After that, you'll have a system image and two empty images.
The next step requires rebuilding the OS. Since you have to use ed, and there's no backspace (at least I haven't figured out how to make backspace work), this is a bit uncomfortable, but here are the commands ready for copy-and-paste after logging in.
Remove additional kernel images we won't need:
rm /rpmx
rm /hpmx
Edit low.s and conf.c to enable tape driver:
chdir /usr/sys/mxsys
e low.s
/tm =/s/0/1/p
w
q
e conf.c
/tm/s/\/\*//
s/\*\///
w
q
Unfortunately this is not enough, if you just rebuild the system like this, it won't boot, and goes into an infinite loop. I didn't dive into the boot process deep enough to figure out why exactly, but the memo linked from the mini-unix page says in passing
A minimum
system has room for 6 or 7 system buffers. As new drivers are added to
the system, the number of system buffers must be decreased if the system
size is maintained at 12K words.
Reducing the number of buffers by one fixed the problem with the booting, so I assume it's some memory layout problem, where loading into some buffer overwrites kernel code or something similar.
A bit of sleuthing finds that the number of buffers is set in param.h, so let's reduce it from 6 to 5:
chdir /usr/sys/mxsys
e param.h
/NBUF/
s/6/5/
w
q
Then param.h looks like
# cat param.h
/*
* tunable variables
*/
#define NBUF 5 /* size of buffer cache */
#define NINODE 50 /* number of in core inodes */
#define NFILE 50 /* number of in core file structures */
#define NMOUNT 2 /* number of mountable file systems */
#define SSIZE 20 /* initial stack size (*64 bytes) */
#define NOFILE 15 /* max open files per process */
#define CANBSIZ 256 /* max size of typewriter line */
#define NCALL 4 /* max simultaneous time callouts */
#define NPROC 13 /* max number of processes */
#define NCLIST 100 /* max total clist size */
#define HZ 60 /* Ticks/second of the clock */
...
Now we rebuild the kernel as newmx:
rm /newmx
chdir /usr/sys/mxsys
sh shs
chdir ../dev
sh shs
chdir ..
sh shld
mv a.out /newmx
ls -l /*mx
sync
The major number of the tape driver is the index in conf.c, so RK is 0, and TM is 1.
If everything worked, use Ctrl E to get back to SIMH, quit, and restart and reboot:
$ simh-pdp11 pdp11.ini
PDP-11 simulator V3.9-0
Disabling CR
Disabling XQ
@newmx
RESTRICTED RIGHTS
USE, DUPLICATION OR DISCLOSURE IS SUBJECT TO
RESTRICTIONS STATED IN YOUR CONTRACT WITH
WESTERN ELECTRIC COMPANY, INC.
;login: root
# /etc/mknod /dev/mt0 b 1 0
# dd if=/dev/mt0 of=/dev/rk1 count=4000 skip=4100
# dd if=/dev/mt0 of=/dev/rk2 count=4000 skip=8100
The count for the second disk (documentation) is a guess, I haven't verified that everything is actually readable, potentially one needs to increase this if needed.
Then you can mount the disks as in Method one.
