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3 usage of read segment, 1 mis-hit (no hit) – FUJITSU MHK2090AT User Manual

Page 205

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Operations

6-16

C141-E088-03EN

READ MULTIPLE

WRITE SECTOR(S)

WRITE MULTIPLE

WRITE VERIFY SECTOR(S)

3)

Caching operation is inhibited by the SET FEATURES command.

4)

Issued command is terminated with an error.

5)

Soft reset or hard reset occurs, or power is turned off.

6)

The device enters the sleep mode.

7)

Under the state that the write data is kept in the data buffer for write
command as a caching data, new write command is issued. (write data kept
until now are invalidated)

6.5.3 Usage of read segment

This subsection explains the usage of the read segment buffer at following cases.

6.5.3.1 Mis-hit (no hit)

A lead block of the read-requested data is not stored in the data buffer. The
requested data is read from the disk media.

The read-ahead operation is performed only when the last sector address of the
previous read command and the lead sector address of this read command is
sequential (see item (2)).

1)

Sets the host address pointer (HAP) and the disk address pointer (DAP) to the
lead of segment.

Segment only for read

DAP

HAP

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