On 1.3 I get these messages during SCSI probe:

ahc0: target 2 synchronous at 10.0MHz, offset = 0xf
probe(ahc0:2:0):  Check Condition on opcode 0x0
    SENSE KEY:  Soft Error
     ASC/ASCQ:  ASC 0x5d ASCQ 0x00
     FRU CODE:  0x31


sd2 at scsibus0 targ 2 lun 0: <SEAGATE, ST423451N, 0006> SCSI2 0/direct
fixed
sd2: 22130MB, 6876 cyl, 28 head, 235 sec, 512 bytes/sect x 45322644
sectors

[...]
ahc1: target 0 synchronous at 10.0MHz, offset = 0xf
sd8 at scsibus1 targ 0 lun 0: <SEAGATE, ST15150N, 0014> SCSI2 0/direct
fixed
sd8: sd8: could not mode sense (4/5); using fictitious geometry
4095MB, 4095 cyl, 64 head, 32 sec, 512 bytes/sect x 8388315 sectors


1.2G also had problems:

ahc0: target 2 synchronous at 10.0MHz, offset = 0xf
probe(ahc0:2:0): soft error (corrected), data = 00 00 00 00 5d 00 31 00
00 00
sd2 at scsibus0 targ 2 lun 0: <SEAGATE, ST423451N, 0006> SCSI2 0/direct
fixed
sd2: 22130MB, 6876 cyl, 28 head, 235 sec, 512 bytes/sect x 45322644
sectors

[...]
ahc1: target 0 synchronous at 10.0MHz, offset = 0xf
sd8 at scsibus1 targ 0 lun 0: <SEAGATE, ST15150N, 0014> SCSI2 0/direct
fixed
sd8: sd8: could not mode sense (4/5); using fictitious geometry
4095MB, 4095 cyl, 64 head, 32 sec, 512 bytes/sect x 8388315 sectors


I guess the difference from 1.2G to 1.3 for sd2 is because of
SCSIVERBOSE in the 1.3 kernel.

Both controllers are Adaptec AHA2940AU, only months old (probe from
1.3):

ahc0 at pci0 dev 17 function 0
ahc0: interrupting at irq 10
ahc0: aic7860 Single Channel, SCSI Id=7, 3 SCBs
scsibus0 at ahc0 channel 0: 8 targets
[...]
ahc1 at pci0 dev 18 function 0
ahc1: interrupting at irq 11
ahc1: aic7860 Single Channel, SCSI Id=7, 3 SCBs
scsibus1 at ahc1 channel 0: 8 targets


sd2 (ST423451N) is exactly one year old, sd8 (ST15150N) is of unknown
age (but probably not much older).

Both disks are heavily(!) used and seem to work OK so I'm not overly
worried, but what could cause this?

The controllers are not set up with anything fancy, but sync negotiation
is turned on for all drives. But then again all my drives are fairly new
and are advertised to work in sync mode...

Gunnar

--
Gunnar Helliesen   | Bergen IT Consult AS  | NetBSD/VAX on a uVAX II
Systems Consultant | Bergen, Norway        | '86 Jaguar Sovereign 4.2
gunnar@bitcon.no   | http://www.bitcon.no/ | '73 Mercedes 280 (240D)