T10 Pi Overview; Table A-1 User Data And Protection Information Format - Oracle StorageTek T10000 Reference Manual

T10 PI Overview

• 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
single protection information interval..

TABLE A-1 User Data and Protection Information Format

Byte 7
0
...
n - 1
n
n + 1
n + 2
n + 3
n + 4
...
n + 7
Each USER DATA field shall contain user data. The size of the user data field is
defined in the Control Data Protection Mode Page.
244 T10000: Interface Reference Manual
defines the placement of protection information in a logical block with a
6 5 4
USER DATA
BLOCK GUARD
BLOCK APPLICATION TAG
BLOCK REFERENCE TAG
Bit
3 2 1 0
August 2016