Solaris Handbook for Sun Peripherals

Target ID Addressing Methods

The target ID is an address that is set on the interface of the device (disk, tape, or CD-ROM). There are three methods to set this address:

Jumpers - an address is achieved by placing jumpers on shunts. This is how internal CD-ROM devices are addressed. If your device requires jumper installation consult the documentation that shipped with your device.

Switch - used when a device is in an external enclosure (an enclosure other than the system chassis), the enclosure provides a switch that you set to your desired target ID address.

Single-connector - A device with a single connector receives data, power, and address information on a single connector. A device of this sort will automatically become addressed when you install it. This is the most common method of addressing Sun disk drives today.

Determining the correct target ID for your device depends on several conditions:

The target addressing method (described above) used by your device.

Existing addresses on the interface - All devices must have a unique target ID.

Device type - some device types such as CD-ROM and tape drives are most easily identified by the operating system when they are with certain addresses. See the table below:

Table A-1 SCSI Target Addresses


Device Order	CD-ROM Targets	Tape Target	Disk Target (Ultra & Enterprise Systems)	Disk Target (Pre-Ultra systems)
1st	6	4	0	3
2nd		5	1	1
3rd			2	2
4th			3	0
5th			4	4
6th			5	5
7th			6	6

Note -

Some SCSI controllers support 7 devices, others support up to 15 devices (although you should take into account the effect on I/O). If 15 devices are connected, valid disk target IDs are 0-14.

Note -

You can not have two devices with the same Target ID on the same SCSI controller. However, target IDs can be reused across different SCSI controllers.