Hitachi HTS541010G9AT00 Specifications - Page 79

Write Cache function, Reassign Function

Page 79 highlights

Table 39: Seek overlap (1) With overlap Host process Device process Seek operation Overhead A Total time = (n-1) * (Seek operation) + A + B (2) Without overlap Host process Device process Seek operation Overhead A B+A Total time = n * (Seek operation + A + B) B B+A B 10.12 Write Cache function Write cache is a performance enhancement whereby the device reports completion of the write command (Write Sector(s) and Write Multiple) to the host as soon as the device has received all of the data in its buffer. The device assumes responsibility to write the data subsequently onto the disk. • Writing data after completed acknowledgment of a write command, soft reset, or COMRESET does not affect its operation but power off terminates writing operation immediately and unwritten data is lost. • Flush cache, Soft reset, Standby, Standby Immediate, and Sleep are executed after the completion of writing to disk media on enabling write cache function. The host system can confirm the completion of Write Cache operation by issuing Flush Cache command, Soft reset, Standby command, Standby Immediate command, or Sleep command, and then confirming the completion of the issued command. 10.13 Reassign Function The Reassign Function is used with read commands and write commands. The sectors of data for reassignment are prepared as the spare data sector. The one entry can register 256 consecutive sectors maximum. This reassignment information is registered internally, and the information is available right after completing the reassign function. Also the information is used on the next power on reset or hard reset. If the number of the spare sector reaches 0 sector, the reassign function will be disabled automatically. The spare tracks for reassignment are located at regular intervals from Cylinder 0. As a result of reassignment, the physical location of logically sequenced sectors is dispersed. Travelstar 5K100 (Serial ATA) Hard Disk Drive Specification 67

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Travelstar 5K100 (Serial ATA) Hard Disk Drive Specification
67
Table 39: Seek overlap
10.12
Write Cache function
Write cache is a performance enhancement whereby the device reports completion of the write command (Write
Sector(s) and Write Multiple) to the host as soon as the device has received all of the data in its buffer. The device
assumes responsibility to write the data subsequently onto the disk.
Writing data after completed acknowledgment of a write command, soft reset, or COMRESET
does not affect its operation but power off terminates writing operation immediately and
unwritten data is lost.
Flush cache, Soft reset, Standby, Standby Immediate, and Sleep are executed after the comple-
tion of writing to disk media on enabling write cache function. The host system can confirm
the completion of Write Cache operation by issuing Flush Cache command, Soft reset, Standby
command, Standby Immediate command, or Sleep command, and then confirming the comple-
tion of the issued command.
10.13
Reassign Function
The Reassign Function is used with read commands and write commands. The sectors of data for reassignment are
prepared as the spare data sector. The one entry can register 256 consecutive sectors maximum.
This reassignment information is registered internally, and the information is available right after completing the
reassign function. Also the information is used on the next power on reset or hard reset.
If the number of the spare sector reaches 0 sector, the reassign function will be disabled automatically.
The spare tracks for reassignment are located at regular intervals from Cylinder 0. As a result of reassignment, the
physical location of logically sequenced sectors is dispersed.
(1) With overlap
(2) Without overlap
Host process
Host process
Device process
Device process
Seek operation
Seek operation
Overhead
Overhead
A
A
B+A
B
B+A
B
Total time = (n-1) * (Seek operation) + A + B
Total time = n * (Seek operation + A + B)