Write Long - HP C2488A Technical Reference Manual

Write Long
The WRITE LONG command requests the Target to write the data transferred by the
Initiator to the media. The data transferred is implementation specific, but will include the
header, data bytes, and the ECC bytes. The READ LONG command is usually issued before
issuing a WRITE LONG command. The WRITE LONG data should be the same length and
in the same order as the data returned by the READ LONG command.
Write Long Command Description Block (COB)
Bit
Byte
7
I
6
1
5
1
4
I
3
I
2
I
1
I
0
00 Opcode = 3FH
01 Logical Unit Number
I
Reserved I'REL=O
02-05 (MSB=02) Logical Block Address
(LSB=05)
06 Reserved
07-08 (MSB=07) Byte Transfer Length (LSB=08)
09 Control Byte
Logical Block Address. This field specifies the logical block address where the write operation
will begin.
Byte Transfer Length. This field specifies the number of data bytes the Target would return
for the READ LONG command. A transfer length of zero indicates that no bytes will be
transferred. This condition is not considered an error.
If a non-zero byte transfer length does not exactly match the data length the Target would
return for the READ LONG command, the Target will terminate the command with a
CHECK CONDITION status and a Sense Key of ILLEGAL REQUEST, and an Additional
Sense Code of INVALID FIELD IN CDB. The ILl and VALID bits will be set to one (1), and
the information bytes will be set to the difference (residue) of the r-equested length minus the
actual length in bytes. Negative numbers will be indicated by two's complement notation.
If the Byte Transfer Length field matches exactly the length that the Target' would return for
the READ LONG command, the Target will write the data to the specified address.
A·62 SCS! Command Descriptions
DRAFT
1/18/93 09:58