Fujitsu MH2060AH - 60GB UDMA/100 5400RPM 8MB 9.5mm Notebook Hard Disk Drive, Руководство по эксплуатации продукта

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Operations
6-12 C141-E195-02EN
6.4 Read-ahead Cache
Read-ahead Cache is the function for automatically reading data blocks upon
completion of the read command in order to read data from disk media and save
data block on a data buffer.
If a subsequent command requests reading of the read-ahead data, data on the data
buffer can be transferred without accessing the disk media. As the result, faster
data access becomes possible for the host.
6.4.1 DATA buffer structure
This device contains a data buffer 8 MB. This buffer is divided into two areas:
one area is used for MPU work, and the other is used as a read cache for another
command. (See Figures 6.7 and 6.8.)
For MPU work For R/W command
For MPU work
8192 KB (8388608 bytes)
304 KB 7824 KB 64 KB
Figure 6.7 Data buffer structure
The read-ahead operation is done by the following commands.
•
READ SECTOR (s) (EXT)
•
READ MULTIPLE (EXT)
•
READ DMA (EXT)
•
READ DMA QUEUED (EXT)
•
READ STREAM PIO
•
READ STREAM DMA