tamir@cs.ucla.edu (Yuval Tamir) (11/19/90)
There have been several messages on the net regarding problems with the
SCSI port on the SLC. These problems seem to be with unexpected resets on
the SCSI bus. Some people report that this is harmless.
Another report said that the resets were causing an Exabyte drive to
rewind and eject the tape unexpectedly in the middle of dumps.
Another report is that the problem occurs with Fujitsu disks when their
read-ahead cache is enabled.
One theory is that the SCSI host adaptor on the SLC is extremely sensitive
to the impedance of your daisy chain. Some people have been able to
eliminate the problem by using a very short (1 meter) cable between the
SLC and the disk. Others have bypassed the problem by using an external
terminator instead of the internal ones. (There is a Sun reference number
560762 for this problem).
Our Sun salesperson says that this has been a problem with only 12 systems
in the entire country. He further says that the problem happens only with
"certain third-party SCSI devices" or when using 3 or more SCSI devices on
the same SLC.
Does anybody have more info on this ? It is not very appealing to
purchase the workstations and later find out that there are problems with
the particular third party disk you have and/or you cannot use the tape
drive you want. Is there anybody from Sun who would care to comment ?
Any estimate on when (if?) a fix can be expected ?
Yuval Tamir
Internet: tamir@cs.ucla.edu
UUCP: ...!{uunet,ucbvax,rutgers}!cs.ucla.edu!tamir