1Automatic Acoustic Management 2============================= 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 46 47