UNIX tape duplicator request

[Doug Gwyn]

In article <26385 at adm.brl.mil> mike at BRL.MIL ( Mike Muuss) writes:
>If you don't know much about the format of the tape, a still better
>command to use is TCOPY (/usr/ucb/tcopy), which will copy tapes that
>have varying record lengths, multiple "files" before tape-EOF ...

I even wrote a version of "tcopy" that uses double-buffering (with
a pair of interlocking processes).  It was a nice exercise, but due
to apparent serious problems in the magtape device driver on our
only remaining system with two tape transports, it didn't run any
faster than the obvious single-process implementation.  It should
have...