External Storage Devices
6.3 SCSI IDs
6.3 SCSI IDs
Every SCSI device attached to a given connector must have a unique SCSI
ID. If two or more devices have the same ID, your workstation won’t operate
correctly.
SCSI storage drives are usually assigned a SCSI ID number at the factory
where they’re made. Certain kinds of drives have certain numbers, and the
numbers are planned in such a way as to make it easy to link different types
of drives together without running into number conflicts.
In some cases, however, a device may have a nonstandard ID, or you may want
to link several of the same kinds of devices together. For these cases, you need
to know how to determine the SCSI IDs of the devices you’re using and how to
change these numbers if necessary.
6.3.1 Factory-Assigned SCSI IDs
Table 6–1 shows the SCSI IDs usually preassigned to each kind of drive.
Table 6–1 Commonly Preassigned SCSI IDs
TYPE OF DRIVE
SCSI ID
Internal hard disk drive
2
Expansion box containing two hard disk
drives
0 and 1
External floppy disk drive
4
CD–ROM drive
4
Tape drive
5
System SCSI connector
7
Because the internal floppy disk drive used in the Personal DECstation is not
a SCSI drive, it does not have an ID.
6.3.2 Verifying SCSI IDs
To check the IDs of the SCSI devices connected to the base SCSI connector on
the back of your system unit, follow these steps:
1. If the workstation software is running, shut it down: Type
shutdown -h
now
and press Return.
2. When you see the console prompt (>>), type
cnfg 3
and press Return.
6–4 External Storage Devices
