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FUJITSU MAV2036RC User Manual

Page 61

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5.4 Checking Operation after Installation and Preparing the HDD for Use

C141-E219

5-9

(2) Caching

parameters

The following parameters are used to optimize HDD Read-Ahead caching operations under the
system environments. Refer to Chapter 3 “Data Buffer Management” of the Serial Attached SCSI
Interface Specifications for further details.

Parameter

Default

value

• IC:

Initiator control

0 (Drive-specific

control (page

cache))

• RCD:

Disabling Read-Ahead caching operations

0 (enabled)

• WCE:

Write Cache Enable

1 (enabled)

• MS:

Specifying the multipliers of "minimum
prefetch" and "maximum prefetch" parameters

0

(Specifying

absolute value)

• DISC:

Prefetch operation after track switching during
prefetching

1

(enabled)

• Number of blocks for which prefetch is suppressed

X'FFFF'

• Minimum prefetch

X'0000'

• Maximum prefetch

X' XXXX'

(1 cache segment)

• Number of blocks with maximum prefetch restrictions

X'FFFF'

• Number of segments

X'08'

Notes:

1. When Read-Ahead caching operations are disabled by the caching parameter, these

parameter settings have no meaning except write cache feature.

2. Determine the parameters in consideration of how the system accesses the disk. When the

access form is not determined uniquely because of the processing method, the parameters
can be re-set actively.

3. For sequential access, the effective access rate can be increased by enabling Read-Ahead

caching operations and Write Cache feature.


(3)

Control mode parameters

The following parameters are used to control the tagged queuing and error logging.

a. Control mode parameters

Parameter

Default

value

• Queue algorithm modifier

0 (Execution sequence of

read/write commands is

optimized.)

• QErr:

Resume or abort remaining suspended
commands after sense pending state

0 (command is resumed)

• DQue:

Disabling tagged command queuing

0 (enabled)

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