Date: Fri, 30 May 1997 13:14:44 +0200 From: Stefan Esser <se@FreeBSD.ORG> To: Robert Schien <robsch@robkaos.ruhr.de> Cc: freebsd-scsi@FreeBSD.ORG, Stefan Esser <se@FreeBSD.ORG> Subject: Re: How to turn off DAT compression Message-ID: <19970530131444.53612@x14.mi.uni-koeln.de> In-Reply-To: <m0wXO8g-00066yC@robkaos.ruhr.de>; from Robert Schien on Fri, May 30, 1997 at 11:38:26AM %2B0200 References: <m0wXO8g-00066yC@robkaos.ruhr.de>
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On May 30, Robert Schien <robsch@robkaos.ruhr.de> wrote: > > I have an Archive Python DAT drive (28388-XXX.494) and want to turn > off the compression mode. The reason is I get NCR timeout messages > (there is a SC-200 in my P6NP5 system) when I write files to tape > which are highly compressible. BTW, when this happens the DAT Hmmm, I don't see how that could cause any problems! I'm using an HP1533 DAT with compression enabled for all my backups, and it never showed the lightest problems ... > is winded back and forth wildly and data which are on earlier This winding forward and backward may indicate a drive problem. Did you remember to clean the R/W head with a cleaning cartridge, at least every 50 hours of use ? (That may be 20 to 50 full backups, depending on your system's specifics ...) > sessions (or partitions or volumes, I don't know what the correct > term is when you have miltiple parts on a tape) are destroyed. Two DAT tapes I > have were so heavily trashed that the DAT drive refused even to to > erase them. Here are some of the error messages: > > May 29 13:46:21 robkaos /kernel: ncr0: have to clear fifos. > May 29 13:46:21 robkaos /kernel: ncr0: restart (fatal error). There should have been some (cryptic :) error message above, which I guess might help. > May 29 13:46:21 robkaos /kernel: st1: COMMAND FAILED (9 ff) @f0637800. > May 29 13:46:27 robkaos /kernel: ncr0: timeout ccb=f0637800 (skip) > May 29 13:47:24 robkaos /kernel: ncr0: timeout ccb=f0658e00 (skip) > May 29 13:47:25 robkaos /kernel: st1: 5.0 MB/s (200 ns, offset 8) > May 29 13:47:25 robkaos /kernel: sd1: 10.0 MB/s (100 ns, offset 8) You got an IBM disk drive ? :) > May 29 13:50:29 robkaos /kernel: ncr0: timeout ccb=f0658e00 (skip) > May 29 13:50:30 robkaos /kernel: st1: MEDIUM ERROR asc:3,2 Excessive write errors Well, this is not a driver message, but a message sent by your drive !!! > BTW, the DAT cartrdges ware brand new (Verbatim). > > Robert > > P.S.: The system is -current (2 weeks old). And the DAT drive ? :) Guess you should first try cleaning your drive's heads. As long as you get the MEDIUM ERROR messages, there is no way I could do anything for you ... Gruss, STefan
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