Finding tape block size

[Anthony DeBoer]

I periodically get tapes from client's systems or other sources where the
precise tape format isn't documented.  What I'm looking to find out is if
there's a way to determine exactly what block size was used when the tape was
written, or even if this is a major requirement (should I even be worrying
about it or not?).  Reading with a tasteful default value usually seems to
work (even a 512-byte block size has worked before, although at tremendous
loss of efficiency), but I'm wondering if there's any chance of data loss with
the wrong block size, or any rule of thumb for optimizing things.

I have several systems here, so as far as naming my hardware/software
configuration goes I'll just mention the Unisys 6000/50 running SVR3.0 with a
150meg QIC drive.  And I shouldn't forget the old Convergent Technologies
Mightyframe.
-- 
Anthony DeBoer NAUI#Z8800 | adeboer at gjetor.geac.com   | Programmer (n): One who
Geac J&E Systems Ltd.     | uunet!geac!gjetor!adeboer | makes the lies the 
Toronto, Ontario, Canada  | #include <disclaimer.h>   | salesman told come true.