Hitachi ULTRASTAR 15K450 HUS154530VLF400 - Manual (Page 310)

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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19.59.1 Combined Header And Data (Mode 00000b)
In this mode, the data to be transferred is preceded by a four-byte header.
Buffer ID must be zero. If another value is specified, no download function is performed and the command is terminated with
Check Condition status. And the drive shall set the sense key to Illegal Request and additional sense code to Illegal Field in
CDB.
Buffer Offset must be zero. If another value is specified, no download function is performed and the command is terminated
with Check Condition status. And the drive shall set the sense key to Illegal Request and additional sense code to Illegal Field
in CDB.
Parameter List Length specifies the number of bytes that shall be transferred during the DATA OUT phase. This number
includes four bytes of header, so the data length to be stored in the drive buffer is transfer length minus four. If the length
exceeds the buffer size, the command is terminated with Check Condition status. And the drive shall set sense key to Illegal
Request and additional sense code to Illegal Field in CDB. A Parameter List Length of less than four (size of header) indicates
no data is transferred.
The 4-byte header consists of all reserved bytes.
Table 247: Write Buffer Header
Byte
Bit
7 6 5 4 3 2 1 0
0-3 Reserved = 0