*BSD News Article 36032


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Newsgroups: comp.os.386bsd.bugs
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!howland.reston.ans.net!swrinde!news.dell.com!tadpole.com!uunet!seas.smu.edu!rwsys!hammy!gordon
From: gordon@sneaky.lonestar.org (Gordon Burditt)
Subject: Re: FreeBSD, fd0d: hard error
Organization: /usr/lib/news/organi[sz]ation
Message-ID: <CwCMrD.4p8@sneaky.lonestar.org>
References: <33j9hp$41l@sol.sun.csd.unb.ca> <34a91e$h2f@sol.sun.csd.unb.ca> <34iv96$ik4@pdq.coe.montana.edu> <34lk6g$d44@orion.cc.andrews.edu>
Date: Sun, 18 Sep 1994 23:33:12 GMT
Lines: 24

>Hmm, could be, I'd like to blame it on the drivers though.. :-)
>I just swapped an IDE controller out for a AHA1542B and I'm getting
>wads-o-errors on the floppy.  I'm going to swap back to the IDE just
>to see if it was that or the new kernel.  Note that I'm using NetBSD
>v1.0_beta. (yeah, one *them* :-) )  I'd like to believe my adaptec,
>my buslogic, my floppy drives, and several of my floppies, are good!

Adaptec's EZ-SCSI manuals note that the default bus-on and bus-off
times on the AHA1542-whatever are long enough to interfere with
floppy or floppy-tape I/O due to DMA starvation.  I'd expect
that the error codes would reflect DMA underrun (writes) or
overrun (reads), which I'm not seeing in the posts, but maybe 
there is a problem with error reporting or retry logic.

Questions to those experiencing the problem:  is a SCSI controller,
especially an AHA1[57]4[02][ABC] also doing I/O at the same time
as the floppy?  (e.g. you're copying to/from your SCSI hard disk,
or paging in a program from it).

Changes to the driver's handling of the bus speed setting might be
the difference that makes the problem show up more often.

					Gordon L. Burditt
					sneaky.lonestar.org!gordon