9 esi data validation, Esi data validation, Section 10.5.3.9 – Seagate Fibre Channel Interface User Manual
Page 138
124
Fibre Channel Interface Manual, Rev. D
Page Length
06h
The maximum length of the ESI page (in bytes).
10.5.3.9
ESI data validation
ESI Data Validation (EDV) provides a mechanism to verify correct data is transferred over the ESI. This func-
tion is optional with support discovered by negotiation. When EDV is enabled, a checksum is calculated and
appended to each ESI transfer phase, ESI command, data, and Enclosure request.
The drive will request ESI data validation when the following occur:
1. The first host request to send or receive ESI data after a power on, a firmware download, or a drive reset
caused by receiving a LIP(AL_PD, AL_PS), a LIP(FF, AL_PS) or a command frame with Target Reset bit
set.
2. If EDV has already been negotiated and then a failure occurs during an ESI transfer which is not the result
of a checksum error being detected.
If ESI data validation is negotiated through EI ESI after events 1 or 2, but before a new ESI command is
received from the host, EDV will not be renegotiated when the host sends the command.
The Parameter Length field for the EDV command phase during EDV negotiation is 00h if the drive initiated
EDV because of a host initiated ESI operation. If the drive is sending an EDV accept because of an enclosure
initiated EDV request, the drive will set the Parameter length to 06h during the command phase for the EDV
accept frame.
For ESI transfers initiated by a SCSI command, the drive will attempt up to two retries if communication with
the enclosure initially fails or if the drive does not detect in discovery that the enclosure is SFF-8067 compliant.
This applies to all product families that support ESI. During each retry the drive attempts the entire transfer
beginning with discovery. If EDV has been negotiated with the enclosure previously, then EDV is renegotiated
after each failed attempt and before the next if the failure does not occur because of a checksum failure.
Field definitions (listed alphabetically)
Action Code
09h
ESI Data Validation Accept.
ESI Page
00h
Identifies the ESI page code used (00h).
Page Length
02h
The maximum length of the ESI page (in bytes).
Table 73:
ESI data validation accept
Bit
Byte
7
6
5
4
3
2
1
0
0
0
0
0
0
ESI Page (00h)
1
0
0
0
0
Action Code (09h)
2
3
(MSB)
Page Length (02h)
(LSB)
4
1
0
1
0
0
1
0
1
5 - 9
Reserved
Table
number