		Tp, Dtp, Itp, Tap & Ntap Archive Programs
		-----------------------------------------

These programs list the table of contents and extract files from tp, dtp
and itp Unix archives. These archive formats were used in 4th to 7th
Edition Unix, and predate tar(1) format. Two programs tap and ntap can
extract files from tap Unix archives, which were used in 1st to 3rd
Edition Unix.


How do I know if my file is in one of the 5 formats?
----------------------------------------------------

Simple. Compile tp, dtp and itp, and try doing a table of contents using
each program:

   % tp t file
   % dtp t file
   % itp t file
   % ntap t file
   % tap 71 t file

If one of them gives something sane-looking, you have probably found the
right one, and you can use the `x' option with the same command to extract
files.

Note that tap and ntap share a common header length, so you need to check
for sane-looking file permissions and timestamps here. The tap format also
stores timestamps in clock ticks, so you have to nominate a starting epoch.
Valid epochs are 71, 72 or 73. It wasn't until ntap and then tp that time
was stored in whole-second units.


Caveats
-------

The programs do not use the checksums available in the archives. If the
archive is corrupt, the programs will merrily extract garbage.

mkdir -p is used to recursively make directory hierachies if they are needed.
This could be recoded, but the programs were hacked up to do what I needed
and I haven't fixed this yet.

The programs have only had a small sample of input archives to extract. Thus,
they may not extract all archives which have the above 5 formats. Bug reports
and patches are most welcome.


Other Notes
-----------

I wrote these to extract archives of this type from old backup tapes. I
hope some other people find the programs useful.

I am _very_ interested in finding programs that can extract from 7th
Edition dump/restor archives, and also from 6th and 7th Edition filesystem
images. If you have any of these or know of them, please email me!

	Warren Toomey	wkt@tuhs.org    August 2019
