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Momentus 5400.3 PATA Blade Server Product Manual, Rev. B
4.1.3 Set Features command
This command controls the implementation of var ious features that the drive supports. When the dr ive r eceiv es
this command, it sets BSY, checks the contents of the Features register, clears BSY and generates an inter-
rupt. 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:
Note. At power-on or after a hardware or software reset the default values of the features are as indicated
above.
Table 7: Features register values
02HEnable write cache (default).
03H Set transfer mode (based on value in Sector Count register).
Sector Count register values:
00HSet PIO mode to default (PIO mode 2).
01HSet PIO mode to default and disable IORDY (PIO mode 2).
08HPIO mode 0
09HPIO mode 1
0AHPIO mode 2
0BHPIO mode 3
0CHPIO mode 4 (default)
20HMultiword DMA mode 0
21HMultiword DMA mode 1
22HMultiword DMA mode 2
40HUltra DMA mode 0
41HUltra DMA mode 1
42HUltra DMA mode 2
43HUltra DMA mode 3
44HUltra DMA mode 4
45HUltra DMA mode 5
05HEnable advanced power management
55HDisable read look-ahead (read cache) feature.
82HDisable write cache.
AAHEnable read look-ahead (read cache) feature (default).
F1HReport full capacity available