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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!nntp.coast.net!zombie.ncsc.mil!news.mathworks.com!fu-berlin.de!zrz.TU-Berlin.DE!cs.tu-berlin.de!uni-erlangen.de!news.tu-chemnitz.de!irz401!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc,comp.periphs.scsi Subject: Re: SCSI-2 Bus Hangs Date: 27 Dec 1995 11:34:31 GMT Organization: Private BSD site, Dresden Lines: 26 Message-ID: <4brb07$b4q@uriah.heep.sax.de> References: <4bju5p$ihj@wilma.widomaker.com> <4bp3bp$7cc@scratchy.mosquito.com> <1995Dec26.123518.1@spcvxb.spc.edu> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.3 Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:11543 comp.periphs.scsi:43927 terry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr.) writes: > Also, the driver should time out a SCSI command that's taking too long > and start recovery, first by retrying the command, then by doing a device > reset to the target, and then doing a complete SCSI bus reset as a last > resort. This is harder than it looks, though - for example, rewinding a > tape should have a much longer timeout than a disk read. The only driver > I know of that does this is the new BusLogic driver for Linux (from ftp. > dandelion.com if I recall correctly). FreeBSD drivers do this already since day 1. However, as you mention, there are some problems that aren't easy to solve. By now, the drivers could be ``tuned'' to assume a particular timeout for a specific command, so for example you could bump the timeout to format a hard disk to two hours (some disks do really take more than one hour for it). I still don't know what's the best method (or where to get reasonable figures for acceptable timeouts). A device or bus reset to a device that's operating normally is about as harmful as a jamming device. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)