Date: Tue, 30 Mar 1999 10:45:32 +0200 From: Ladavac Marino <mladavac@metropolitan.at> To: 'Matthew Dillon' <dillon@apollo.backplane.com>, Bob Bishop <rb@gid.co.uk> Cc: avalon@coombs.anu.edu.au, Wilko Bulte <wilko@yedi.iaf.nl>, jkh@zippy.cdrom.com, hackers@FreeBSD.ORG Subject: RE: another ufs panic.. Message-ID: <97A8CA5BF490D211A94F0000F6C2E55D097576@s-lmh-wi-900.corpnet.at>
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> -----Original Message----- > From: Matthew Dillon [SMTP:dillon@apollo.backplane.com] > Sent: Tuesday, March 30, 1999 9:58 AM > To: Bob Bishop > Cc: avalon@coombs.anu.edu.au; Wilko Bulte; jkh@zippy.cdrom.com; > hackers@FreeBSD.ORG > Subject: Re: another ufs panic.. > > > Nobody in their right mind turns off parity checking on a SCSI > bus. > ( At least, anyone who does is beyond any help that hackers can > give > them ). This line of debate is becoming pointless. > [ML] Another point in case (okay, it is a bit wild goose) but years ago I have had problems with my SCSI disk which not even parity could detect (in fact, raw device writes and reads displayed bit errors). Eventually I have discovered that an IDE disc was probably generating a lot of electrical noise on the bus (even when not spoken to). As soon as I have removed the IDE disc, the bit errors simply disappeared (and haven't reappeared ever since). This is a venue worth of research. Funny enough, I did not have any problems when accessing that particular IDE disk. On the second thought, I think that the noise propagated through the power supply, because the bit errors were there even when the IDE disc was disconnected from the "controller" but still attached to the power. I guess the errors were actually generated somewhere in the analog part of the SCSI disc (but I could not tell where since the parity and ECC control in the disc should have detected that, but I am not altogether sure if I have had the proper mode page bits turned on--it was the L-thing--yes, that long ago--and they did not have scsi(8)/camcontrol(8) at that time): Darren, this could possibly be your problem as well since you seem to have a lot of hardware hanging off the same power supply--prehaps it just cannot regulate any more. You could test that by writing a known pattern to the raw device and then reading it back--just make sure that the tar runs on EIDE drive writing into the bit-bucket so that the EIDE does not spin down and that it keeps seeking--both actions take a lot of power. /Marino > -Matt > Matthew Dillon > <dillon@backplane.com> > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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