Figure 9: External SCSI Connectors
SCSI comes with a variety of connectors, both internal and external. The table above describes some of the connectors based on which version of SCSI you are using.
Figure 10: Internal SCSI Cable
One of the primary differences between SCSI and ATA adapters is the number of devices one port supports. SCSI supports either 8 or 16 devices, depending on the version you are using, with the SCSI adapter card being one device. Each device has a unique SCSI ID in the chain, from 0-7 or 0-15. The SCSI host adapter is typically SCSI ID 7 – the ID with the highest priority on a narrow (8 device) or wide (16 device) host adapter.
Figure 11: HD68 LVD SCSI Terminator
The other difference between SCSI and other types of drive connections is that the SCSI “chain” of devices has to be terminated on each end. A terminator tells the SCSI host adapter that it’s connection is the last in the chain of SCSI connections. Typical SCSI host adapter cards (or integrated SCSI ports on motherboards) have a built-in terminator. If you are using external SCSI devices, a lot still use a terminator device which plugs into one of the SCSI ports on the device to signal it is the last device in the SCSI chain.
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