README.acoustic
1Automatic Acoustic Management
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3
4Most modern harddisk drives have the ability to speed down the head movements
5to reduce their noise output. The possible values are between 0 and 254. 128
6is the most quiet (and therefore slowest) setting and 254 the fastest (and loudest).
7Some drives have only two levels (quiet / fast), while others may have different
8levels realized between 128 and 254.
9
10To be able to use this with hdparm, you will need a current kernel with the -ac patches
11applied. Maybe the kernel of your favorite distribution will already include this (SuSE
12has it in their current kernel, for example).
13Just try to compile hdparm, type "hdparm" and have a look for "-M" in the output. If it
14doesn't appear, your kernel most likely doesn't support it.
15
16You can get the acoustic setting by typing
17
18 hdparm -M /dev/hda
19
20To set the most quiet mode use
21
22 hdparm -M 128 /dev/hda
23
24For the fastest setting use
25
26 hdparm -M 254 /dev/hda
27
28Now test different values and try to hear the difference. :-)
29
30Not all disk drives support this setting - and the speed impacts may also vary between
31different manufacturers and models.
32
33If you see lines like
34
35 kernel: hdb: task_no_data_intr: status=0x51 { DriveReady SeekComplete Error }
36 kernel: hdb: task_no_data_intr: error=0x04 { DriveStatusError }
37
38in your syslog, then your harddisk will most likely not support Acoustic Management.
39
40Perhaps you also wanna have a look on the IBM Feature Tool, available at
41http://www.storage.ibm.com/hdd/support/download.htm.
42
43I would welcome any feedback to <gernot@hillier.de>
44
45Gernot
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