Resolution:
Place the 68 pin drive at the end of the bus and set the jumpers for the drive for active
termination, which provides termination to all 68 pins. If the drive does not provide termination,
the converter should provide on board termination so that all unused lines are terminated.
Ÿ
The termination for a drive should match the interface type of the drive. For example,
single-ended drives should use single-ended terminators
ü
Cables and connectors
Ÿ
Ensure that the cables are seated tightly and that no pins are bent.
Ÿ
If possible, try replacing the cable and terminators and use the drive’s internal termination.
Ÿ
Make sure that pin 1 of the cable is plugged into pin 1 of the SCSI connector. Pin 1 on the SCSI
cable is normally identified by a red or red-striped wire. This is especially important if you are
using cables or connectors (on the SCSI adapter) that are not keyed. The connectors on IBM
drives have a slotted key to prevent you form plugging the cable in backwards but not all SCSI
cables are made with a key.
ü
Ensure that the drive is jumpered to enable auto start when power is applied.
ü
Try resetting the SCSI adapter defaults:
Ÿ
Enable “Reset IC Initialization”
Ÿ
Disable “plug and play” SCAM support
Ÿ
Enable “Unit Start” command
Ÿ
Enable synchronous and wide negotiations if available
ü
Ensure that the drive is jumpered to disable sync negotiations.
ü
Does the drive spin up and remain spinning?
ü
Does the SCSI adapter recognize the drive during boot up?
ü
Check that the cable lengths are within the ANSI specification for the interface transfer rate used and
the number of devices installed on the bus. For a definition of the specifications, see the SCSI Trade
Association page at the following Internet address:
http://www.scsita.org/terms/scsiterms.html
ü
If the drive is attached through a removable carrier, try removing the drive from the carrier and
attaching the drive directly to the bus.
ü
If you are using a narrow bus/cable (50 pin) with a wide (68 pin) device and a wide SCSI adapter, try
disabling wide negotiation in the adapter settings.
ü
LVD devices are backward compatible with single-ended adapters as long as the system and the
drives are configured correctly. When attaching LVD devices to single-ended, wide or narrow
adapters, the following applies:
Ÿ
LVD drives have do not provide termination on the drive.
IBM storage products
Page 23
IBM Technology Group Support Center
07N5612IG10
