Intergraph TD-x10 Setup, System Reference Manual

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You can add up to five external single-ended SCSI devices to a desktop workstation, and up to seven
external single-ended SCSI devices to a deskside workstation. The number of devices and length of the
cables used to connect the devices becomes a factor when using Fast SCSI-2 or Ultra SCSI devices.
Ultra-SCSI devices impose shorter cable restrictions than Fast SCSI-2 or SCSI-1. The total length of
the SCSI cabling must not exceed the following:
Number of Devices SCSI-1 Fast SCSI-2 Ultra SCSI
1 to 4 19.8 feet (6 meters) 9.9 feet (3 meters) 9.9 feet (3 meters)
5 to 7 9.9 feet (3 meters) 9.9 feet (3 meters) 4.9 feet (1.5 meters)
NOTE The SCSI controller (integrated or on an option board) counts as one device.
NOTE The AIC 7860 in the desktop system can be configured to transfer data at Fast SCSI-2 rates for all
devices. This allows Ultra SCSI devices to be installed without being hampered by the Ultra SCSI
cable restrictions. Total cable length can then be extended to the Fast SCSI-2 length. See “Disabling
SCSI Sync Negotiation” later in this chapter to configure the controller.
When attaching drives to the system’s SCSI port on the I/O connector board, the total length of the
SCSI cabling is the sum of all of the following:
u
SCSI bus trace length on I/O expansion board - 12.0 inches (30.5 cm)
u
SCSI cable inside the base unit - 41 inches (104 cm)
u
SCSI cable inside each device (average) - 8 inches, (20 cm)
u
SCSI cable between the base unit and the first device
u
SCSI cable between each device
If attaching SCSI drives to an optional SCSI adapter, the total length of the SCSI cabling is the sum of
all of the following:
u
SCSI cable inside the system (101.6 mm)
u
SCSI cable inside each external device (203.2 mm)
u
SCSI cable between the base unit and the first device
u
SCSI cable between each device
Connecting the Device
To add an external SCSI device:
1. Connect the SCSI cable to the SCSI port on the base unit and to the device.
2. Set the device’s SCSI ID to an unused number (1, 2, 3, 5, or 6). By default, the following devices
use pre-defined SCSI IDs:
−
System disk drive uses ID 0.
−
CD-ROM drive uses ID 4.
−
SCSI bus uses ID 7.
3. Disable or enable the device’s SCSI termination according to the vendor’s instructions. The last
external device on the SCSI cable chain must have SCSI termination enabled. All other external
devices must have SCSI termination disabled.
4. If necessary, install the device drivers and configure the device according to the vendor’s
instructions.