How to mount a tar file in v7 running in SimH
This was difficult to figure out, but perseverance, tuhs, and simh mailing lists helped.
Modern tar files are easy to mount as tapes in SimH (theoretically):
In SimH:ATTACH TM0 -V -F TAR whatever.tar
In guest (v7):
But, some tar files (back in the day stuff), don't work this way. In order to get them to work requires some work.
1. Get Wolfgang Helbig's enblock program - http://doc.cat-v.org/unix/v6/operating-systems-lecture-notes/v6/enblock.c
2. compile it and put it somewhere useful - ~/bin or somesuch
cc -o enblock enblock.c
cp enblock ~/bin/
3. Get a useful old tarball - https://www.tuhs.org/Archive/Distributions/UCB/2bsd.tar.gz
4. Unzip the tarball and enblock it
cat 2bsd.tar | enblock > 2bsd.tap
5. Do the simh/v7 dance
att tm0 2bsd.tap
tar: bin/ - cannot create
x bin/csh, 40412 bytes, 79 tape blocks
tar: bin/etc/ - cannot create
x bin/etc/htmp, 0 bytes, 0 tape blocks
x bin/etc/install, 81 bytes, 1 tape blocks
Don't worry too much about the cannot create messages - the dirs get created.