On Thu, Jul 25, 2002 at 10:15:23PM +0400, Rustam Kadyrov wrote:
> >> What kind of disk is sd4 ?
> 
> sd4 at scsibus2 target 2 lun 0: <SEAGATE, ST15150W_APL, 9503> SCSI2 0/direct
> fixed
> sd4: 4095 MB, 3712 cyl, 21 head, 107 sec, 512 bytes/sect x 8388315 sectors
> sd4: sync (100.0ns offset 8), 16-bit (20.000MB/s) transfers, tagged queueing

Could it be that this disk has problems with tagged queuing ?
As an experiment could you play with the number of allowed tags ?
this is in sys/dev/ic/siop.c, function siop_attach():
	sc->sc_c.sc_adapt.adapt_max_periph = SIOP_NTAG - 1;

SIOP_NTAG - 1 is 254; try to lower it to maybe 16, or 32.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
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