The 'e-pi' tape was overwritten at least twice. Originally, it contained
patents/papers in *roff format, and was then overwritten with a set of UNIX V2
binaries. Afterwards, some early UNIX V3 binaries were appended, and finally,
everything was replaced with source code for programs that calculated e and
pi.

I have recovered everything recoverable and identified all the binaries.
'[chess_fragment]' appears to be a fragment of the chess program, though I'm
not sure which version of UNIX it's intended for (it sits before the V2 files
yet uses /dev/vt0). Files in the 'v2' directory are all V2 binaries. '[f43]'
is 2K of space between the V2 and V3 binaries on the tape, possibly just slack
space data from two writes to the tape. Files in the 'v3' directory are all V3
binaries. '[paper*]' are the patents/papers that have survived.

There is a possibility that the V2 bins belong to V2 proper, as they're all
PDP-11/20 bins with V2 headers. In contrast, most of the bins from the
's1'/'s2' tapes are V1 bins. Some of them are identical to those from the 's2'
tape, and if the timestamps from the 's2' tape can be trusted, they're from
May/June 1972.

The V3 bins are most likely from late 1972 or early 1973, but no later than
Feb 1973, as they've been overwritten by files from Feb 1973. This suggests
they're from a V3 beta, supported by the fact that some features described in
the V3 manual are missing. The files were laid out in perfect alphabetical
order on the tape.