Strange timeout problems with C1533a under NT4

[Rod Stevenson]

We have a C1533a Tape attached to a dual processor box running NT4. The device is purely to perform backups for the SQL Server also resident on the same machine. We are using only HP and Sony DDS2 tapes.
Occasionally the SCSI controller is reporting (via system event log) 'The device \Device\SCSIPort0\ did not respond within the timeout period'
We've double checked cable, id and terminators and everything appears correct. One issue that seems improbable but possibly could be the cause is the SCSI parity setting. The SCSI controller is embedded on an 'American Supermicro' motherboard (P6DGU). It has an Adaptec 7890 chipset supporting both LVD and Ultra/SE buses. The tape is obviously on the Ultra/SE bus, along with a Plextor CD-ROM drive. The configuration for the SCSI controller has parity enabled. However for a standard PC installation the C1533a does not appear to have any jumpers for parity - the dip switch on the underside of the unit is claimed to be for 'Unix' installations.
Is it possible to set the parity on a C1533a unit when it is for a PC/Windows NT installation.
Also any other suggestions as to the cause of the 'timeout' would be most appreciated.
cheers.

[Bob_196]

The very first thing I would do is to look into isolating the tape drive on it's own controller. Preferably a PCI card - try an older ADAPTEC 2940UW (or 2940U, 2940 U2W). this way you only have the tape drive accessing that controller and bus. If that doesn't clear up the SCSI timeouts then it's time to do some more extensive trouble shooting into the drive.

[Munir_1]

Also you could this:, adjust the SCSI BIOS settings for the corresponding ID of the tape drive:

Sync negotiation should be disabled
Wide negotiation should be disabled
Max transfer should be no higher than 10
Disconnect should be enabled
Send Start Unit Command should be set to no