Read-Ahead Cache; Data Buffer Configuration - Fujitsu MPD3XXXAT Product Manual

6.5

Read-Ahead Cache

After a read command which reads the data from the disk medium is completed, the read-
ahead cache function reads the subsequent data blocks automatically and stores the data in the
data buffer.
When the next command requests to read the read-ahead data, the data can be transferred from
the data buffer without accessing the disk medium. The host can access the data at higher
speed.
6.5.1

Data buffer configuration

The device has a 512-KB data buffer. The buffer is used by divided into two and other
commands parts; for MPU work, for read cache of read commands and other commands (see
Figure 6.9).
for MPU work
40.5 KB
(41,472 bytes)
The read-ahead operation is performed at execution of the READ SECTOR(S), READ
MULTIPLE, or READ DMA command, and read-ahead data are stored in the buffer for read
cache.
512 KB (524,288 bytes)
for R/W command
471.5 KB (482,816 bytes)
Figure 6.9 Data buffer configuration
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