3-18 Dell Dimension XPS D
xxx
Systems Reference and Troubleshooting Guide
6&6,,'1XPEHUVEach device attached to a SCSI host adapter card, as well as the card itself, must have
a unique SCSI ID number from 0 to 7. The SCSI host adapter card is typically config-
ured as SCSI ID 7. The boot hard-disk drive must be configured as SCSI ID 0. Any
other SCSI devices attached to the SCSI host adapter card can be configured for any
SCSI IDs from 1 to 6. Refer to the documentation for each device for instructions on
configuring its SCSI ID.
NOTE: There is no requirement that SCSI ID numbers be assig ned seq uentially o r that
devices be attached to the cable in order by ID number.
6&6,&DEOHVDQG6&6,7HUPLQDWLRQThe SCSI standard requires termination at two end points. If only internal devices are
connected, the SCSI host adapter card is terminated at one end. The device end of
the cable must th en be terminated i n one of two ways: eith er the cable cont ains a ter-
minator, or the device attached to the end co nnecto r must be term inated . How e v er, if
you have both internal and external devices attached to the SCSI host adapter card,
the card should have termination disabled. External SCSI cables do not have termina-
tors, so termination must be enabled on the external SCSI device itself. Any devices
attached to inner connectors on the SCSI cable should have termination disabled.
Refer to the documentation for each device for instructions on enabling and disabling
termination.
The type of cabling you receive with a SCSI device de pen ds on the type of de vice y ou
are installing:
If you are installing an internal narrow SCSI device (such as a CD-ROM drive or
tape drive)
, you have a 50-pin internal SCSI cable as shown in Figu re 3-14. One
end of this cable attaches to the SCSI host adapter card. The three connectors on
the other end of the cable are used for attaching up to th ree nar ro w SCSI d e vices
installed in the externally accessible d ri ve bays.
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68-pin SCSI cable
(to hard-disk drive)
50-pin SCSI cable
(to device in
externally accessible
drive bay)