5.4Checking Operation after Installation and Preparing the HDDs for Use
(2)Caching parameters
The following parameters are used to optimize HDD
| Parameter |
| Default value |
|
|
|
|
• IC: | Initiator control |
| 0 |
|
|
| control (page |
|
|
| cache)) |
• RCD: | Disabling |
| 0 (enabled) |
• WCE: | Write Cache Enable |
| 1 (enabled) |
• MS: | Specifying the multipliers of "minimum |
| 0 (Specifying |
| prefetch" and "maximum prefetch" parameters |
| absolute value) |
• DISC: | Prefetch operation after track switching during |
| 1 (enabled) |
| prefetching |
|
|
• 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
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
3.For sequential access, the effective access rate can be increased by enabling
(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 |
| 0 (command is resumed) |
| commands after sense pending state |
|
|
• DQue: | Disabling tagged command queuing |
| 0 (enabled) |