Reserve Element (10) - 56h

The library reserves the entire library for the initiator making the request. Only whole logical unit reservations are allowed; individual element reservations are not supported. The reservation remains in effect until either the initiator that made the reservation sends a RELEASE command, or a reset or power-cycle of the library occurs.

This command is only supported if the library control path is provided by a tape drive.

Note: DA blades connected to drives that also configure a partition control path, may report certain library ready conditions differently than drives that are configured to host a partition control path.

This command should be used to reserve the library for extended operations, such as issuing a SEND VOLUME TAG followed by a REQUEST VOLUME ELEMENT ADDRESS sequence. Initiators issuing a RESERVE should follow it with a RELEASE when the extended operation sequence is complete.

The RESERVE ELEMENT CDB format is shown in the following table.

Table 1: RESERVE ELEMENT CDB format

Bit Byte	7	6	5	4	3	2	1	0
0	Op Code (57h)
1	Logical Unit Number			3rdPrty	Reserved		LongID	Rsvd
2	Reserved
3	Third Party Device ID
4 : 6	Reserved
7 : 8	MSB Parameter List Length LSB
9	Control

Field	Description
3rdPrty	This field is not supported, and must be set to 0.
LongID	This field is not supported, and must be set to 0 as IDs greater than 255 are not supported.
Third Party Device ID	This field is required and used only when the 3rdPrty bit is set. Since the 3rdPrty bit is not supported, this field must be set to 0.
Parameter List Length	This field is not supported, and must be set to 0.