Technical data

SCSI Cable Guidelines

If you are using a SCSI adapter card, this information also applies.

The number of drives and length of the cables used to connect the drives becomes a factor when using

SCSI-1, Fast SCSI (SCSI-2), Ultra SCSI, and Ultra Wide SCSI drives. Fast SCSI, Ultra SCSI, and

Ultra Wide SCSI impose shorter cable restrictions than SCSI-1. The total length of the SCSI cabling

must not exceed the following:

Drives

SCSI-1 Fast SCSI-2 Ultra SCSI Ultra Wide SCSI

1 to 4 19.8 feet (6 meters) 9.9 feet (3 meters) 9.9 feet (3 meters) 9.9 feet (3 meters)

5 to 7 9.9 feet (3 meters) 9.9 feet (3 meters) 4.5 feet (1.5 meters) 4.5 feet (1.5 meters)

NOTE The SCSI controller (on the system board or an adapter card) counts as one device.

The total length of the SCSI cabling is the sum of the following:

SCSI cable inside the base unit - 6.0 inches (15 cm)

SCSI cable inside each device - average 8 inches, (20 cm)

SCSI cable between the base unit and the first device

SCSI cable between each device

Connecting the Drive

To add an external SCSI drive:

1. Connect the SCSI cable to the SCSI port on the base unit and to the device.

2. Set the drives SCSI ID to an unused number (1, 2, 3, 5, or 6). By default, the following devices

use these SCSI IDs:

−

System disk drive uses ID 0.

−

CD-ROM drive uses ID 4.

−

SCSI bus uses ID 7.

3. Disable or enable the drive’s SCSI termination according to the vendor’s instructions. The last

external drive on the SCSI cable chain must have SCSI termination enabled. All other external

drives must have SCSI termination disabled.

4. If necessary, install the software drivers and configure the drive according to the vendor’s

instructions.

Disabling Sync Negotiation

Use the following instructions if you need to disable the sync negotiation, which forces the controller

to transfer data at a specified rate (slower than its capability) for the target drives.

To disable sync negotiation:

1. Power off the system and reboot into DOS using the SYSUTIL diskette.

2. From the SYSUTIL main menu, select SCSISelect Utility.

3. From the Options box, select Configure/View Host Adapter Settings.