[TUHS] decoding 1972_stuff/s1-bits

[random832@fastmail.us (Random832)]

I'm sorry if this has been done before, but I could find no indication 
this was the case in the unix archive itself or in any of the months I 
checked in the mailing list.

I have figured out what the first 50176 bytes of s1-bits are.

It is an "INIT Tape" as described in Dennis_v1 Boot Procedures(VII) and 
Dennis_v3 bproc.8. It is apparently contemporary with s2 [all of the 
files on it /etc/getty /bin/ls and so on match up exactly with their 
counterparts on s2], and this would seem to make s2 the "/bin-/etc-/lib 
tape" described in bproc.8.

Also - is there any other known copy of the "bos" bootloader? I'm 
partway through hand-disassembling the one on the tape.

Anyone know how to get SIMH to send ^J for return?

Anyway - with the KE-11A enabled you need to use "d system sr" to set 
the switch register [which must be set to 1 to cold boot, 73700 to come 
up in single user mode, and any random value other than the special ones 
0 57500 10 20 40 1 2 to come up normally]

The RF disk is not even large enough to contain the whole s2 tape, and 
while even v1 supported mountable filesystems, there is no mkfs or mount 
on the tapes.