SCSI Specifications
| SCSI Standard Number/Name | Bus Width | Throughput (MBps) | Cable Pin Count | Signaling | Max Devices
(Incl. Host Adapter) |
Max Length (M) |
| SCSI-1/ “Regular” SCSI | 8 | 5 | 50 | SE | 8 | 6 |
| HVD | 8 | 25 | ||||
| SCSI-2/
Fast SCSI Fast narrow |
8 | 10 | 50 | SE | 8 | 3 |
| HVD | 8 | 25 | ||||
| SCSI-2/
Fast wide SCSI |
16 | 20 | 68 | SE | 16 | 3 |
| HVD | 16 | 25 | ||||
| SCSI-3/SPI
Ultra SCSI |
8 | 20 | 50 | SE | 8
4 |
1.5*
3 |
| HVD | 8 | 25 | ||||
| SCSI-3/SPI
Wide Ultra SCSI Fast Wide 20 |
16 | 40 | 68 | SE | 16
4 |
1.5*
3 |
| HVD | 16 | 25 | ||||
| SCSI-3/SPI-2
Ultra2 SCSI |
8 | 40 | 50 | LVD | 8 | 12 |
| SCSI-3/SPI-2
Wide Ultra 2 SCSI |
16 | 80 | 68 | LVD | 16 | 12 |
| SCSI-3/SPI-3
Ultra 160 SCSI |
16 | 160 | 68 | LVD | 16 | 12 |
| SCSI-3/
Wide Ultra 3 SCSI Ultra 320 |
16 | 320 | 68 | LVD | 16 | 12 |
*5 or more devices: 1.5 meters. 1-4 devices: 3 meters.
**25 M cable can be used only when connecting a single device
Note: For bus width, 8 bits = “narrow” and 16 bits = “wide.” 8-bit SCSI always accepts 8 devices, 16-bit SCSI always accepts 16 devices.
Note: HVD cable always has a max length of 25 meters. LVD cable always has a max length of 12 meters.
Common SCSI ID Assignments:
ID 0 – Bootable Hard Disk
ID 7 – Host Adapter
ID 3 – CD/DVD