TC11/Cypher Tape Drive Problem (Software? Hardware?)

[rr at gt-cmmsr.UUCP]

I am having trouble with my Cypher 920 tape drive and Emulex TC11 controller
under 4.3 BSD Unix (the problem did not show itself until I brought up 4.3)
on a VAX 11/780.  The problem shows itself by giving a Bus Grant Late <BGL>
error whenever I do a tape dump or tar at 1600 bpi.  Whenever I use 800 bpi,
everything works fine.  DEC replaced the PE card (but not the controller card)
with the same BGL error.

Strange Happenings:

	When I take the system down to single user, 1600 bpi works fine
	with tar.  Dump, however, complains that it runs out of tape <EOT>
	after 1666 feet when it has actually run through 2300 feet.

	I recompiled the 4.2 version of dump under 4.3 and tried to do a
	tape dump in multiuser mode.  On occasion I got through a couple
	of tapes without getting the EOT error, however, I still got the
	BGL error most of the time.  Under single user,  dump4.2 works
	fine.

	I only have one tape drive on my system.  When I boot the generic
	version of unix supplied with the 4.3 distribution, however, I get
	2 drives identified (Normally, only 1 shows up):

		tm0 at uba0 csr 172520 vec 224, ipl 15
		te0 at tm0 slave 0
		te1 at tm0 slave 1

	All other devices on the system are identified with the correct
	number under the generic unix.

If you have any ideas, I would appreciate the help.  Thanks.

-Richard


-- 
Richard Robison

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