Date: Fri, 14 Mar 1997 22:01:01 +0100 From: j@uriah.heep.sax.de (J Wunsch) To: scsi@FreeBSD.ORG Cc: gilbertd@cs.man.ac.uk (David Alan Gilbert) Subject: Re: Medium errors Message-ID: <19970314220101.SM26356@uriah.heep.sax.de> References: <9703141151.AA26882@amu7.cs.man.ac.uk>
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As David Alan Gilbert wrote: > Perhaps I didn't make myself clear; I want to understand more about > the way defect lists are stored and processed. In Ye'olde MFM drive > it was the OS which used the defect list while working on the drive; > now I presume its the drives job? But if thats so why does the Sun > have so much to firtle with it? With SCSI, you can normally have both ways. Normally, the drive will handle its bad block lists, and provide automatic remapping. For most drives, you can also turn it off, and do the remapping in software. I've seen some commercial systems doing this, probably mostly since they could use the same code for ST-506 and SCSI by this, and get an error notification and consistent media defect handling between ST-506, ESDI, and SCSI. FreeBSD relies on the drive's remapping features, and the SCSI disk driver doesn't even offer you the opportunity to use bad144. > Can you give me a full path, machine name and all to that - I can't > find it. src/tools/tools/scsi-defects/scsi-defects.pl Relative to the source tree base of your closest FreeBSD mirror, in FreeBSD-current. (It's also in 2.2-GAMMA now, but only since a couple of days.) > > dd if=/dev/zero of=/dev/rsd0 count=15 > > disklabel -Brw sd0 auto > > No (well I didn't put the -B in); I fdisk'd first, but I also tried > just fdisk'ing and just disklabeling (I think) - nothing gave > a happy result. Probably. disklabel auto might not cooperate well with fdisk- organized disks, i never tested this case in any way, nor am i very interested in fdisk-organized disks at all. I simply consider the fdisk table something fairly obsoletish on my systems. (And have been cursing the HP folks since their newest NetServer LC even *ignores* its hard disk if the BIOS thinks it's smarter and the fdisk table doesn't look what it believes were reasonable! HP is a true Windows company these days.) The only thing i guarantee you for disklabel auto is that the above sequence is supposed to work. I don't promise you anything about fdisk (obviously :). -- 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. ;-)
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