(3)Caching parameters (page code = 8)

The following parameters are used to optimize HDD Read-Ahead caching operations under the system environments. Refer to Chapter 2 "Data Buffer Management" of the SCSI Logical Interface Specifications for further details.

 

Parameter

 

Default value

• IC:

Initiator control

 

0 (HDD-specific

 

 

 

control (page

 

 

 

cache))

• RCD:

Disabling Read-Ahead caching operations

 

0 (enabled)

• WCE:

Write Cache Enable

 

1 (enabled)

• MF:

Specifying the multipliers of "MINIMUM

 

0 (Specifying

 

PRE-FETCH" and "MAXIMUM PRE-

 

absolute value)

 

FETCH" parameters

 

 

• DISC:

Prefetch operation after track switching during

 

1 (enable)

 

prefetching

 

 

• DISABLE PRE-FETCH TRANSFER LENGTH

 

X'FFFF'

• MINIMUM PRE-FETCH

 

X'0000'

• MAXIMUM PRE-FETCH

 

X' 0000'

• MAXIMUM PRE-FETCH CEILING

 

X'FFFF'

• NUMBER OF CACHE 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.

(4)Control mode parameters (page code = A)

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

92

C141-E270

Page 96
Image 96
Fujitsu MBA3073NP, MBA3073NC, MBA3300NP Disc, Disable PRE-FETCH Transfer Length Xffff Minimum PRE-FETCH, Maximum PRE-FETCH