Some Notes on This Table

Transfer Mode / Defining Standard / Bus Width (bits) / Bus Speed (MHz) / Through- put (MB/s) / Special Features / Cabling / Signaling Method / Maximum Devices Per Bus / Maximum Cable Length(m)
"Regular"
(SCSI-1) / SCSI-1 / 8 / 5 / 5 / 50-pin / SE / 8 / 6
HVD / 8 / 25
Wide SCSI / SCSI-2 / 16 / 5 / 10 / 68-pin / SE / 16 / 6
HVD / 16 / 25
Fast SCSI / SCSI-2 / 8 / 10 / 10 / 50-pin / SE / 8 / 3
HVD / 8 / 25
Fast Wide SCSI / SCSI-2 / 16 / 10 / 20 / 68-pin / SE / 16 / 3
HVD / 16 / 25
Ultra SCSI / SCSI-3 / SPI / 8 / 20 / 20 / 50-pin / SE / 8 / 1.5
4 / 3
HVD / 8 / 25
Wide Ultra SCSI / SCSI-3 / SPI / 16 / 20 / 40 / 68-pin / SE / 8 / 1.5
4 / 3
HVD / 16 / 25
Ultra2 SCSI / SCSI-3 / SPI-2 / 8 / 40 / 40 / 50-pin / LVD / 8 / 12
2 / 25
HVD / 8 / 25
Wide Ultra2 SCSI / SCSI-3 / SPI-2 / 16 / 40 / 80 / 68-pin / LVD / 16 / 12
2 / 25
HVD / 16 / 25
Ultra3 SCSI / SCSI-3 / SPI-3 / 16 / 40 (DT) / 160 / Fast-80, CRC, DV, QAS, Packet / 68-pin / LVD / 16 / 12
2 / 25
Ultra160(/m) SCSI / SCSI-3 / SPI-3 / 16 / 40 (DT) / 160 / Fast-80, CRC, DV / 68-pin / LVD / 16 / 12
2 / 25
Ultra160+ SCSI / SCSI-3 / SPI-3 / 16 / 40 (DT) / 160 / Fast-80, CRC, DV, QAS, Packet / 68-pin / LVD / 16 / 12
2 / 25
Ultra320 SCSI / SCSI-3 / SPI-4 / 16 / 80 (DT) / 320 / Fast-160, ? / 68-pin / LVD / 16 / 12
2 / 25

Some notes on this table:

·  "(DT)" means that transfer mode uses double transition clocking.

·  Throughput numbers are in decimal megabytes per second.

·  To keep the table from getting cluttered, I've only mentioned current cabling, not obsolete cables.

·  The number of devices includes the host adapter.

·  For Ultra and faster speeds, the maximum length of cable for some signaling types depends on the number of devices on the chain; thus, the multiple rows.

·  Ultra320 specifications are not final as of this writing.