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Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!info-vax
From: info-vax@ucbvax.ARPA
Newsgroups: fa.info-vax
Subject: uVAX disk controller warning.
Message-ID: <5572@ucbvax.ARPA>
Date: Mon, 18-Mar-85 10:00:41 EST
Article-I.D.: ucbvax.5572
Posted: Mon Mar 18 10:00:41 1985
Date-Received: Tue, 19-Mar-85 04:37:06 EST
Sender: daemon@ucbvax.ARPA
Organization: University of California at Berkeley
Lines: 26

From: Richard Garland <OC.GARLAND@CU20B.ARPA>

I have been told by one of our department's of a micro VAX-I disk 
controller problem (RQDX1) which they say was verified by RDC:

Each time you power on the uVAX, the disk controller flags a good block
as bad (My contact thought the particular block was random).

This has 2 effects:

	1) The disk is slowly but surely renderred unusable as your files
	get corrupted.

	2) Even if the good-bad blocks are not in files, performance
	degrades due to the other more well known problem with the
	controller:  The controller microcode is so slow that after
	you get around 12 bad blocks to revector, you lose a whole revolution
	on each disk read or write (since it must look through the
	revectoring table each time.)

There is supposed to be a uCode update to fix the false bad block
problem.  Meantime, don't turn off your microVAXen, and make sure
field service knows you need/want the controller micro-code fix.

					Rg
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