Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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18.2 Information Units
SCSI-FCP defines a number of IUs that are used to describe the mapping of SAM Device and Task Management functions.
The Disk Profile defines an 'FCP Feature Set', which is a subset of those IUs.
This section defines the IUs implemented by the drive (see Table88).
Table 88:Information Units (IUs)
IU SAM primitive Data block F/M/L SI M/O
CAT Content
T1 Command Request 6 FCP_CMND F T M
T6 Data Out action 1 FCP_DATA M T M
I1 Data delivery request 5 FCP_XFER_RDY (WRITE) M T M
I3 Data In action 1 FCP_DATA M H M
I4 Response 7 FCP_RSP L T M
Note:
Key:
SAM = SCSI-3 Access Method
IU = Information Unit
CAT = Information category of Device_Data frame
F/M/L = First/Middle/Last IU of Sequence
SI = Sequence Initiative
H = Hold Sequence Initiative
T = Transfer Sequence Initiative
M/O = Mandatory/Optional