Sony SDX-700C, Product Specifications Manual

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5.SCSI Interface
SONY AIT-3 drive SDX-700 series Ver.2.1
5-11
Bits 4-3 Reserved.
Bits 2-0 LUNTRN: These bits specify a logical unit number in a target, and must always be set to ZERO as the
unit is a single target, single logical unit device on the SCSI bus. The Logical Unit Number for the drive is
fixed and is set to ZERO. Any other value will cause the unit to enter the status phase reporting CHECK
CONDITION with the sense key set to COMMAND ABORTED.
Therefore, only the values 80h and C0h are supported.
When sent from a target to an initiator during reconnection, an implied RESTORE POINTERS message will be
performed by the initiator prior to completion of this message, since at no time will a RESTORE POINTERS be sent.
5.3.13.
IGNORE WIDE RESIDUE (23h)
Table 5-5: Ignore Wide Residue Message
Byte Value
0 23 Message Code
1 01 Ignore
The IGNORE WIDE RESIDUE message (see table 5-5) shall be sent from the SDX-700C to indicate that the number
of valid bytes sent during the last REQ/ACK handshake and REQB/ACKB handshake of a DATA IN phase is less
than the negotiated transfer width. The ignore field indicates the number of invalid data bytes transferred. This
message shall be sent immediately following that DATA IN phase and prior to any other messages. The ignore field
is defined in table 5-6.
More than one IGNORE WIDE RESIDUE message may occur during an I/O process.
Table 5-6: Ignore Field
Ignore Invalid data bits
16-bit transfers
00h Reserved
01h DB
(15-8)
02-FFh Reserved
Even though a byte is invalid its corresponding parity bit shall be valid for the value transferred.
5.4.
Status Specification
A Status byte is sent from the drive to the Host during the STATUS phase at the termination of each command as
specified in the SCSI specification, unless the command has been cleared by an ABORT message, by a BUS
DEVICE RESET message, or by a hard RESET.
The Status bytes that will be return are:
00h GOOD: This status indicates that the drive has successfully completed the command.
02h CHECK CONDITION: Any error, exception, or abnormal condition that causes sense data to be set returns
CHECK CONDITION. The REQUEST SENSE command should be sent following this status to determine
the nature of the error.
08h BUSY: The drive is busy. This status is returned whenever the drive is unable to accept a command from
an otherwise acceptable initiator. The BUSY status will be returned by the unit, if, while it is
DISCONNECTED from the SCSI bus, it receives a command from a different initiator. The unit does not
stack commands and therefore will not accept the next command until the current one has completed.
Note that if an initiator sends overlapped commands to the unit (i.e.: it sends a new command while the
previous one is still executing and the unit is disconnected) then the first command will be aborted and a
CHECK CONDITION will be returned to the initiator to indicate that the command was aborted. The
second command will NOT be executed.
The BUSY status returned by the drive must not be confused with DRIVE NOT READY. DRIVE NOT
READY will be returned as part of the Sense data following a REQUEST SENSE command and indicates
that the drive is off-line and no media is loaded in the drive.