Sun Oracle Storage Tek T10000, Справочное руководство

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E20425-01 • 237
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Data Integrity Validation
This appendix contains information about the Data Integrity Validation (DIV)
feature for the T10000 tape drive. This feature is based on the ANSI T10
Technical Committee's implementation of the Data Integrity Field (DIF).
The terms DIV or DIF are also referred to as Protection Information (PI).
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Data Integrity Validation
Oracle’s StorageTek T10000-Series tape drive supports the Data Integrity
Validation (DIV) feature. This feature provides end-to-end protection of user
data during a transfer.
Initiators generate the Protection Information (PI) during a write operation.
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Any object associated with the I_T_L nexus
1
(such as the Host: application or
host bus adapter; Target: controller or device) may check for this information.
Once the device receives the protection information (for example, written to
tape), it keeps this information until overwritten. Any loss of power, hard reset, or
a logical unit reset has no effect on the retention of this protection information.
Protection information is appended to the end of the record using the following
format for the PI data.
• The Logical Block field contains the original user data.
• The Protection Information field contains the CRC.
Notes:
1. The capability of the drive to support DIV is advertised in Inquiry data and
Mode Sense data.
2. To enable or disable DIV protection mode—use the Mode Select command.
3. Once enabling DIV mode; only the following commands are affected:
• Read (08h)
• Verify (13h)
• Write (0Ah)
1. I_T_L nexus: A nexus is a connection that exists between an initiator, a target, and a
logical unit. This is where one Initiator Port talks to one Target Port, addressing one LUN
and together they execute one Task.
Logical Block Protection Information (4-byte CRC)