I/O Interfaces
Parallel SCSI
SCSI Bus Limitations
25 metres
12 metres
� Fast Wide SCSI: � Ultra2 SCSI LVD:
� 5 – 80 MB/s � 40 – 320 MB/s
� 25 metres total � 12 metres total
SCSI bus limitations:
At fairly low speeds (10 to 20 MB/sec) the SCSI parallel bus is capable
of operating over a total cable length of 25 metres (Fast Wide SCSI).
At the higher speeds required today (80 to 160 MB/sec) and using some
expensive circuitry, this distance has been reduced to 12 metres total
length (Ultra 160).
Ultra SCSI using the Single Ended interface is limited to 1.5 metres.
SCSI buses are also limited by the maximum number of devices that can
be connected together on the cable (16 devices in Wide SCSI).