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Fujitsu MAP3147 Computer Drive User Manual

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3.1 Control/Sense Commands

C141-E167 3 -

51

3.1.18.1.2 READ RESERVATIONS

In the READ RESERVATION service action, the drive transfers the following information to the

initiator as a parameter data list.

• Current generation value (See Section 3.1.18.2)

• Reservation keys registered by initiators that keep persistent reservations

• Scope value and type value

• Scope-specific address (only the Element scope)

When the READ RESERVATION service action is executed, if no persistent reservation is held by

the drive, zero is set in the Additional Length field, which is transferred as parameter data, on the

list.

3.1.18.2 PERSISTENT RESERVE IN parameter data for READ KEYS

The format for parameter data transferred in the READ KEYS service action of the PERSISTENT

RESERVE IN command is shown below.

Bit

Byte

76543210

0(MSB)

Generation

3(LSB)

4(MSB)

Additional Length (n-7)

7(LSB)

8(MSB)

First reservation key-1

15 (LSB)

n-7 (MSB)

Last reservation key-m

n(LSB)

The "Generation" field contains a 32-bit counter value maintained by the driver. This counter value

is incremented every time the PERSISTENT RESERVE OUT command requests execution of the

REGISTER, REGISTER AND IGNORE EXISTING KEY, CLEAR, PREEMPT, or PREEMPT

AND ABORT service action.

Header

~

~

~

~

~

~

~ ~

~

~ ~

~

Reservation

key list

~ ~

~

~ ~

~

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