A P P E N D I X A - Ultra320 SCSI Configuration

A P P E N D I X A

Ultra320 SCSI Configuration

This appendix provides general information about Ultra320 SCSI configuration rules. This appendix discusses the following topics:

Target Devices

Bus Length

Cabling and Termination

SCSI Symbols

Target Devices

For Ultra320 SCSI performance of up to 320 Mbytes/sec, there can be a maximum of 15 devices connected to each port on the host adapter.

The available target addresses (SCSI IDs) for each port on the host adapter are 0 through F.

Note - SCSI ID 7 is reserved for the host adapter.

Bus Length

The maximum SCSI bus length is determined by the SCSI bus type (that is, the number of devices connected).

TABLE A-1 shows the maximum SCSI bus lengths for Ultra320 SCSI with an 8/16-bit bus width.

TABLE A-1 Bus Restrictions
SCSI Type	Peak Mbytes/sec	Single-Ended		LVD
	Peak Mbytes/sec	Max Length (Meters)^[1]	No. of Devices	Max Length (Meters)*	No. of Devices
SCSI-2 Narrow Wide	10 20	3 3	8 16	25 12 25 12	2 8 2 16
SCSI-3 Ultra1 Narrow Wide	20 40	1.5 3 1.5 3	8 4 8 4	25 12 25 12	2 8 2 16
SCSI-3 Ultra2 Narrow Wide	40 80	N/S ^[2] N/S	N/S N/S	25 12 25 12	2 8 2 16
SCSI-3 Ultra3 Narrow Wide	80 160	N/S N/S	N/S N/S	25 12 25 12	2 8 2 16
SCSI-3 Ultra320 Narrow Wide	160 320	N/S N/S	N/S N/S	25 12 25 12	2 8 2 16

Cabling and Termination

In order to maintain Ultra320 SCSI performance, all cables used must be Ultra320 SCSI compliant. In addition, the SCSI bus must be correctly terminated. Most Sun devices use auto-termination. For more information, see the documentation that came with the device.

This host adapter has active terminators with an automatic means of enabling and disabling the termination. The termination circuit derives its power from the PCI or SCSI bus. When the PCI bus power is removed, active SCSI termination is maintained if the other SCSI device supplies power to the Term Pwr pins of the SCSI bus.

SCSI Symbols

One of the four following symbols is placed near a SCSI port to indicate which type of SCSI the port is using. The icon might appear alone or with descriptive text.

SE LVD LVD/MSE HVD

Acronym	Meaning
SE	Single-ended
LVD	Low-voltage differential
MSE	Multi-mode single-ended
HVD	High-voltage differential

^{1 (TableFootnote) This maximum length must include the internal bus length of your system. Sun qualifies cable lengths of only up to 10 meters (22.8 feet).}

^{2 (TableFootnote) N/S = not supported}