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.
Set up the SIMH init file (named install.ini here)
You'll get a bunch of output:
Now just press RETURN. This will prepare the blank 'system.tu56' image for use.
Next, you'll see the following:
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.
Finally, just press RETURN. This will copy the required files to the new system tape image.
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
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.