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Form of Names in /dev/scsi
Each device special filename in the /dev/scsi directory reflects the values of the device's adapter (bus) number, SCSI ID, and logical unit number (LUN).
Tip: The character between the SCSI ID and the LUN in these names is the letter "l." When reading or copying these device names, take care not to write a digit 1 instead. This is a frequent error.
Names of SCSI Devices on a SCSI Bus
Devices attached directly to a SCSI bus have names in this form:
| sc | Prefix "sc" for SCSI attachment. |
| 0 to 137 | Number of the SCSI adapter, typically 0 or 1. |
| d | Constant letter "d" for device. |
| 0 to 7 (to 15 for wide SCSI) | SCSI ID of the target device or control unit, as set by switches on the device itself. |
| l (letter ell) | Constant letter "l" for logical unit. |
| 0 to 7 | Logical unit number (LUN) of this device, typically 0. |
A typical device name would be /dev/scsi/sc1d3l0 meaning a SCSI device configured as ID 3 on SCSI bus 1. Either this device has no logical units, or this is the first logical unit on device 3.
Names of SCSI Devices on the Jag (VME Bus) Controller
Machines in the Challenge and Onyx systems can optionally have SCSI devices attached to the VME bus through a bridge using the jag device driver. These devices are also represented in /dev/scsi with names of the following form:
| jag | Prefix "jag" for VME/SCSI attachment. |
| 0 to 4 | Number of the VME adapter, typically 0 or 1. |
| d | Constant letter "d" for device. |
| 0 to 7 (to 15 for wide SCSI) | SCSI ID of the target device or control unit, as set by switches on the device itself. |
| l (letter ell) | Constant letter "l" for logical unit. |
| 0 to 7 | Logical unit number (LUN) of this device, typically 0. |
A typical device name would be /dev/scsi/jag1d3l0 meaning a SCSI device configured as ID 3 on VME bus 1. Either the device has no logical units, or this is the first logical unit on device 3.
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