Dell TL2000 manual Figure A-4. Configuration of a Four Partition System

Drive 4

Element Address

256

Drive 3

Element Address

256

Drive 2

Element Address

256

Drive 1

Element Address

256

Magazine Magazine

24

Magazine	Magazine
1	3

Front side

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Figure A-4. Configuration of a Four Partition System

SCSI Element Addressing

Every logical library starts at the first drive slot with the current assigned element start address (default value 256). It will be incremented from the bottom to the top slots for every drive slot. There is one exception to this addressing scheme to accommodate libraries currently in the field. A 4U library which contains only full height drives will continue to have the addresses assignments 256 and 257, thus causing no interruptions to their operation. Drive slots will still be incremented by 1 for each drive slot position.

Note: Exchanging drives with different form factors will result in the library needing to be reconfigured.

4U Unit with only FH drives (1 logical library)

SCSI Element Slot

4

257

3

2

256

1

4U Unit with FH and HH drives (1 logical library)

SCSI Element	Slot
258	4
	3
257	2
256	1

Figure A-5. Examples of SCSI Element Addressing

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The SCSI specification does not allow gaps in the SCSI element addressing. Special handling is needed for empty drive slots to fulfill the specification. Also drives which are temporarily removed need to have their address preserved to not confuse the attached host and host application. Generally only drives are reported which are currently physically available or temporarily removed. Empty (unused) slots which are located at the bottom or the top should not be reported, with an exception in case of a “removed” condition. A drive slot which does not contain a drive and has a position between used slots needs to be reported as a SCSI element. To signal the host application that this slot is not usable, its ACCESS bit will be disabled.

Appendix A. SCSI Element Types and Addresses A-5