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Path: sserve!newshost.anu.edu.au!munnari.oz.au!ariel.ucs.unimelb.EDU.AU!werple.apana.org.au!news From: andrew@werple.apana.org.au (Andrew Herbert) Newsgroups: comp.os.386bsd.bugs Subject: Re: Those NetBSD hard-drive hangs... Date: 10 Jul 1993 10:41:51 +1000 Organization: werple public-access unix, Melbourne Lines: 26 Message-ID: <21l38f$42t@werple.apana.org.au> References: <9319017.15979@mulga.cs.mu.OZ.AU> NNTP-Posting-Host: werple.apana.org.au summer@ee.mu.OZ.AU (Mark Summerfield) writes: >I, too, had problems with NetBSD 0.8 hanging with the hard-drive light on. >... I removed the >/dev/drum device driver, and replaced it with a plain file (i.e. "touch >/dev/drum"). I haven't had the problem since (and the system has had a few >workouts compiling various things, including a couple of kernels). >So, basically I'm happy with this as a workaround, but I'm curious to know >*why* it works, and what other effects it may have. I don't really >understand the details of the way paging works, so I don't know what >/dev/drum is usually used for. /dev/drum is used to access the swap area. On a system with just one swap region it is basically equivalent to that swap region - i.e. /dev/rsd0b, /dev/rwd0b or similar, depending on your hardware. If you have multiple swap partitions in use, /dev/drum interleaves all these to form a single logical partition. A problem in the sd driver (/sys/scsi/sd.c) allowed unpalatable transfer lengths - anything that was not a multiple of 512 bytes - to be sent to the scsi controller, which may then hang. The problem is fixed in netbsd-current. I have not seen this occur in my (limited) testing of a wd-based system. Andrew