T10 PI Overview
244 T10000: Interface Reference Manual August 2016
• Read (08h)
• Verify (13h)
• Write (0Ah)
4. The transfer lengths (CDB bytes 2-4) for these commands must include the
additional 4 bytes of Protection Information.
5. During Reading or Writing with DIV mode enabled the Target returns a Check
condition if a PI miscompare is detected
T10 PI Overview
The T10 PI model provides for protection of user data while it is being transferred
between a sender and a receiver. Protection information can be generated by a Disk
storage controller or it can be generated at the application layer and may be checked
by any object associated with the I_T_L nexus (see SAM-4). Once received, protection
information is retained (for example, written to medium, stored in non-volatile
memory, or recalculated on read back) by the device server until it is overwritten.
Power loss, hard reset, logical unit reset, and I_T nexus loss shall have no effect on
the retention of protection information.
Support for protection information shall be indicated in the PROTECT bit in the
standard INQUIRY data (see SPC-4).
Protection Information is also referred to as the Data Integrity Field (DIF) or Data
Integrity Validation (DIV).
TABLE A-1 defines the placement of protection information in a logical block with a
single protection information interval..
Each USER DATA field shall contain user data. The size of the user data field is
defined in the Control Data Protection Mode Page.
TABLE A-1 User Data and Protection Information Format
Byte
Bit
76543210
0
USER DATA
...
n-1
n BLOCK GUARD
n+1
n + 2 BLOCK APPLICATION TAG
n+3
n+4
BLOCK REFERENCE TAG
...
n+7
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