Notes on OS/8

Installation

I wanted to install OS/8 from the two distribution DECtape images, AL-4711C-BA and AL-4712C-BA. These DECtapes contain the original distribution of OS/8 V3Q, dated July 1977.

The first tape (AL-4711C-BA) is bootable from the TC08 DECtape controller, but not from the TD8E DECtape controller. It boots into a running OS/8 environment.

The second tape (AL-4712C-BA) is bootable from the TD8E DECtape controller, but not from the TC08 DECtape controller. It boots into a TD8E initializer that will initialize a blank DECtape and copy the system files from the first tape onto it.

Therefore, if you're running a simulated PDP8 with a TC08 controller (the dt device in simh), you can just boot directly off of a copy of the first tape.

If you're running a simulated PDP8 with the TD8E controller (the td device), on the other hand, you need to follow the TD8E initialization procedure by booting from tape #2 (AL-4712C-BA) to make a working copy of OS/8 that can boot from the TD8E.

  1. Set up the SIMH init file (named install.ini here)

    ;; Enable TD8E/TU56 DECtape set td enabled ;; Disable TC08/TU56 DECtape set dt disabled ;; Set TD0 write-locked set td0 locked att td0 AL-4761C-BA.tu56 ;; Attach a blank image to td1 att td1 system.tu56 ;; RK05 disk pack att rk0 rk05.dsk
  2. Run simh

    $ pdp8 boot.ini PDP-8 simulator V4.0-0 Beta       git commit id: db964d12 TD0: 12b format, buffering file in memory sim> boot td0
  3. You'll get a bunch of output:

    TD8E INITIALIZER PROGRAM VERSION 7A 12K SYSTE MOUNT A CERTIFIED DECTAPE ON UNIT 1 WRITE-ENABLED ALWAYS KEEP ORIGINAL SYSTEM DECTAPES WRITE-LOCKED STRIKE A CHARACTER TO CONTINUE

    Now just press RETURN. This will prepare the blank 'system.tu56' image for use.

  4. Next, you'll see the following:

    DISMOUNT SYSTEM TAPE #2 FROM UNIT 0 AND SAVE IT MOUNT ORIGINAL SYSTEM TAPE #1 ON UNIT 0 PREPARE TO COPY FILES OVER STRIKE A CHARACTER TO CONTINUE

    At this point, break into the emulator by typing ^E (Control+E), which will return you to the sim> prompt. At the simh prompt, dismount td0 and mount the original distribution tape.

    Simulation stopped, PC: 00302 (JMP 301) sim> detach td0 TD0: writing buffer to file sim> attach td0 AL-4711C-BA.tu56 TD0: 12b format, buffering file in memor sim> continue

    Finally, just press RETURN. This will copy the required files to the new system tape image.

    COPYING FILES FROM UNIT 0 TO UNIT 1 REMOVE AND SAVE TAPE ON UNIT 0 TAKE NEW TAPE (ON UNIT 1) WHICH WAS JUST CREATED AND PLACE IT ON UNIT 0 IT IS YOUR NEW OS/8 SYSTEM TAPE STRIKE A CHARACTER TO CONTINUE
  5. Now, following the instructions, break into the simh emulator again by pressing ^E, dismount both td0 and td1, and mount the new system tape on td0

    sim> detach td1 TD1: writing buffer to file sim> detach td0 TD0: writing buffer to file sim> attach td0 system.tu56 TD0: 12b format, buffering file in memory sim> c
  6. Finally, just press RETURN, and you'll be greeted by the OS/8 prompt, a single period. This means OS/8 is running from the new system tape image.

    .

    You can type DIR at the prompt to get a list of files on the tape.

    .DIR ABSLDR.SV 5 CCL .SV 18 FOTP .SV 8 DIRECT.SV 7 EDIT .SV 10 PAL8 .SV 19 CREF .SV 13 PIP .SV 11 BOOT .SV 5 LOADER.SV 12 SABR .SV 24 FORT .SV 25 RESORC.SV 10 LIBSET.SV 5 BUILD .SV 33 SET .SV 14 SRCCOM.SV 5 BITMAP.SV 5 DTCOPY.SV 5 TDCOPY.SV 7 DTFRMT.SV 7 TDFRMT.SV 9 RXCOPY.SV 6 MCPIP .SV 13 CAMP .SV 13 EPIC .SV 14 PIP10 .SV 17 HELP .SV 8 RKLFMT.SV 9 LIB8 .RL 29 315 FREE BLOCKS .