Read Long - HP C2488A Technical Reference Manual

Read Long
The READ LONG command requests the Target to transfer a specific block of data to the
Initiator. The data transferred will include all header, data, and ECC (Error Correction
Code) bytes.
Read Long Command Descriptor Block (COB)
Bit
Byte
7
J
6
J
5
I
4
I
3
I
2
I
1
I
0
00
Opcode= 3EH
01
Logical Unit Number
I
Reserved
I
CORRCT
I
RelAdr=O
02-05
(MSB=02) Logical Block Address (LSB=05)
06 Reserved
07-08
(MSB=07) Byte Transfer Length (LSB=08)
09 Control Byte
CORRCT (Corrected). A CORRCT bit of one (1) instructs the Target to correct the data
by ECC before transferring it to the Initiator. A CORRCT bit of zero (0) causes the logical
block to be read and transferred without any error detection or correction.
Logical Block Address. This field specifies the starting address for the Read Long operation.
The operation will continue for the length specified by the Byte Transfer Length field.
Byte Transfer Length. This field should specify exactly the number of bytes available for
transfer. If a non-zero transfer length does not exactly match the available data length, the
target will terminate the command with a Status of CHECK CONDITION, a Sense Key of
ILLEGAL REQUEST, and an Additional Sense Code of INVALID FIELD IN CDB. The
Valid and ILl bits will be set to one (1), and the information field will be set to the difference
(residue) of the requested lenght minus the requested length in bytes.
A byte transfer length of zero indicates that no bytes will be transferred and wil not be
considered an error.
A~36
SCS! Command DeScriptions
DRAFT
1/18/93 09:58