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5.3.11. BUS DEVICE RESET (0Ch)
This message is sent from an initiator to direct a target to clear all current commands. Upon recognizing this
message, the currently executing command will be aborted and the drive will proceed to the BUS FREE state. The
drive will then execute a hard reset which will leave the drive in a state as if it had been power-cycled. All data in
the buffer will be written to tape before the reset is performed.
A BUS DEVICE RESET message should be used to reset the drive, rather than a hard reset, as this will only reset
the drive rather than all the devices on the bus.
Due to the catastrophic nature of this command, it should be used cautiously in a multiple initiator system.
5.3.12. IDENTIFY (80h-FFh)
These messages are sent by either the initiator or the target to establish the physical connection path between an
initiator and target for a particular logical unit. This message byte can have the following bits set:
Bit 7
This bit is always set to one to distinguish these messages from other messages.
Bit 6
This bit is only set to one by the initiator. When set to one, it indicates that the initiator has the ability to
disconnect and reconnect.
Bit 5
LUNTAR: This bit is always ZERO to indicate that the LUNTRN field below is valid.
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)
Byte
The IGNORE WIDE RESIDUE message (see table 5-5) shall be sent from the SDX-1100V 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.
Even though a byte is invalid its corresponding parity bit shall be valid for the value transferred.
SONY AIT-5 drive SDX-1100V series Ver.1.0
Table 5-5: Ignore Wide Residue Message
Value
0
23
1
01
Table 5-6: Ignore Field
Ignore
00h
01h
02-FFh
Message Code
Ignore
Invalid data bits
16-bit transfers
Reserved
DB (15-8)
Reserved
5.SCSI Interface
5-11
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