Reserve Unit Command - Fujitsu C150-E049-02EN Oem Manual

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RESERVE UNIT Command

The RESERVE UNIT command (Table 3.8) is used to reserve
logical unit for the exclusive use of the requesting initiator to another
specified SCSI device.
Table 3.8 RESERVE UNIT Command
Bit 7 6
Byte
0
1 Logical Unit Number 3rdPty Third Party Device ID Reserved
2
3
4
5
The RESERVE UNIT and RELEASE UNIT commands provide the
basic mechanism for contention resolution in multiple-initiator
systems.
This command requests that the entire logical unit be reserved for
the exclusive use of the initiator until the reservation is superseded by
another valid RESERVE UNIT command from the initiator that
made the reservation or until released by a BUS DEVICE RESET
message from any initiator, by a hard reset condition, or by a power
on cycle. The reservation shall not be granted if the logical unit is
reserved by another initiator. It shall be permissible for an initiator to
reserved a logical unit that is currently reserved by that initiator.
If the logical unit is reserved for another initiator, the target shall
return RESERVATION CONFLICT status.
3rdPty:
Third Party Device ID: 000b (Reserved)
5 4 3
Operation Code (16h)
Reserved
Reserved
Reserved
Control
0b (Reserved)
M3099GX/GH OEM Manual
2 1 0