Device Identification on ADAC Ultra2 S466

All logical drives on each SCSI bus are identified to the host as ID 0. Differentiate the drives with Logical Unit Identifiers (LUNs). ID 0 cannot be used for non-disk devices because they are limited to IDs 1 through 6. The ADAC Ultra2 S466 is limited to eight logical drives because LUNs are used to present logical drives. The SCSI-2 ANSI specification has a limit of eight LUNs per ID. The SCSI-3 specification increased the number of LUNs to 16. An example of ID mapping follows.

Example of ADAC Ultra2 S466 ID Mapping

 

ID

 

Channel 1

 

 

0

 

A1-1

 

 

1

 

A2-1

 

 

2

 

CD

 

 

3

 

A2-5

 

 

4

 

CD

 

 

5

 

A4-1

 

 

6

 

Optical

 

 

7

 

Reserved

 

 

8

 

A5-2

 

 

9

 

A5-6

 

 

10

 

A6-1

 

 

11

 

A6-4

 

 

12

 

A6-7

 

 

13

 

A7-2

 

 

14

 

A7-5

 

 

15

 

A7-8

 

 

 

 

 

 

As Presented to the Operating System

ID

 

LUN

 

 

Device

 

ID

 

LUN

 

Device

0

0

 

 

Disk (A1-X)

1

0

 

Scanner

0

1

 

 

Disk (A2-X)

2

0

 

CD

0

2

 

 

Disk (A3-X)

3

0

 

Tape

0

3

 

 

Disk (A4-X)

4

0

 

CD

0

4

 

 

Disk (A5-X)

5

0

 

Tape

0

5

 

 

Disk (A6-X)

6

0

 

Optical

0

6

 

 

Disk (A7-X)

 

 

 

 

 

 

 

0

7

 

 

Disk (A8-X)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

68ADAC Ultra2 S466 Hardware Guide