Anyone familiar with this format, I've got about
200 6" tapes that all say
 TDX Format or TDX Tape.
 I've found nothing about it through Google, these were used on a Vax 11/780
 under either VMS or UCB Unix 4.1, unclear as to which OS.    Standard TU78
 was used.    This is all I know so far...
 Is this some kind of compression format or something?   Any help on this
 would be greatly appreciated, thanks. 
They may be tapes for a Sentry tester.  A development system was available
for VMS and there was a program to read and write TDX tapes for exchanging
data and programs with the tester.  If I remember correctly TDX stood for
Tester Data eXchange.
This may be a completely different TDX format.  Is there any other information
on the labels?
--
Eric Dittman
dittman(a)dittman.net