Seagate Medalist 3220, Руководство по эксплуатации продукта

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3.2.3 Set Features command
This command controls the implementation of various features that the
drive supports. When the drive receives this command, it sets BSY,
checks the contents of the Features register, clears BSY and generates
an interrupt. If the value in the register does not represent a feature that
the drive supports, the command is aborted. Power-on default has the
read look-ahead and write caching features enabled. The acceptable
values for the Features register are defined as follows:
02
H
Enable write cache (default)
03
H
Set transfer mode (based on value in Sector Count register)
Sector Count register values:
00
H
Set PIO mode to default (PIO mode 2)
01
H
Set PIO mode to default and disable IORDY (PIO mode 2)
08
H
PIO mode 0
09
H
PIO mode 1
0A
H
PIO mode 2 (default)
0B
H
PIO mode 3
0C
H
PIO mode 4
20
H
Multiword DMA mode 0
21
H
Multiword DMA mode 1
22
H
Multiword DMA mode 2
40
H
Ultra DMA mode 0
41
H
Ultra DMA mode 1
42
H
Ultra DMA mode 2
55
H
Disable read look-ahead (read cache) feature
82
H
Disable write cache
AA
H
Enable read look-ahead (read cache) feature
(default)
F1
H
Report full capacity available
At power-on, or after a hardware reset, the default values of the features
are as indicated above. A software reset also changes the features to
default values.
Medalist 6540, 5130 and 3220 Product Manual, Rev. A 29