4.2 dist tape

[William P. Malloy]

This article is both a warning and a (minor) flame.

We have FINALLY, after many months, received our 4.2 tapes.  ITT's lawyers
must charge by the hour from all the time they took to get us our 4.2 license.
Anyway, being good little boys, and not trusting anything (paranoia is a virtue)
we tried to make a copy of the tapes.  I figured easy!  We've got two drives, a
TU-77 and a TU-78, all we need is to do is ``dd if=/dev/rmt5 of=/dev/rmt12''.
Works fine, then I do it again (there are six files on the first tape).  We
begin to notice a curious thing, one drive is cranking along a whole lot
faster then the other (we may be a confused bunch, but we can tell how fast
things go round and round.)  Well we try everything, dd bs=512, everything,
we do cmp on the files, and find the first one is okay, but nothing else works.

Luckily I read the manuals (like WOW, literate!) And I remembered a curious
phrase which goes, "The tapes are 9-track 1600 BPI and contain some 512-byte
records followed by many 10240-byte records."  Yeah you guessed it, the SOME
refers to the first file on the tape (the boot), and everything else needs
to have ``bs=10240'' option to dd.  Now why didn't anyone TELL people this?
We were going nuts trying to figure it out, we tried everything even the
basic ``cp /dev/rmt5 /dev/rmt12'' and no luck.

I guess the point is (a) most people don't back up their distribution tapes
(some people LIKE living dangerously), or (b) most people don't have two
tape drives or (c) everyone thought it was a good chuckle and wanted to see
what other people thought of it.  Well here's the warning if you're thinking
of converting to 4.2, watch out and save this article.

Maybe the people who are doing the distribution just thought it would be
a good giggle to see how many people really bother to back-up their distrib-
ution.  From the lack of complaints either (a) no one bothers or (b) we must
have a STRANGE configuration which caused our problems.

Well at least I've improved, the first time I ever touched a tape drive I
crashed a system.  That's why I work for the ``Software'' Support Group.
--
Address: William P. Malloy, ITT Telecom, B & CC Engineering Group, Raleigh NC
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