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From: mangler@cit-vax.UUCP
Newsgroups: comp.unix.questions
Subject: Re: TU-78 tape drives and EOT
Message-ID: <1798@cit-vax.Caltech.Edu>
Date: Mon, 16-Feb-87 05:08:56 EST
Article-I.D.: cit-vax.1798
Posted: Mon Feb 16 05:08:56 1987
Date-Received: Mon, 16-Feb-87 20:17:54 EST
References: <646@cygnet.CYGNETSYSTEMS>
Distribution: na
Organization: California Institute of Technology
Lines: 17
Summary: Cipher always writes minimum gaps

In article <646@cygnet.CYGNETSYSTEMS>, will@cygnet.CYGNETSYSTEMS (Will Nelson) writes:
> The Cypher on the remote machine is constantly "shoe-shining",
> ie, goes forward a bit, rewinds a bit less, back and forth at 6250,
> whereas the TU-78 never rewinds.

Cipher streamers are strict about adhering to the gap-length
standards, they always write exactly the minimum gap, unlike
other streamers which write gaps up to twice as large if they
need to in order to keep streaming.  This makes Cipher's very
hard to stream without a cache.  That's why cache is standard
on most Cipher models.

Some start/stop GCR drives write 0.6 inch gaps.  The TU-78
is similar to the TU-77, a drive that writes 0.6 inch gaps;
perhaps the TU-78 falls in this class?

Don Speck   speck@vlsi.caltech.edu  {seismo,rutgers,ames}!cit-vax!speck