Last Update:
July 2006



Automatic Acoustic Management (AAM)

ATA-AC displays the following information on the Automatic Acoustic Management (AAM) feature of ATA Hard Disc Drives:

a) Does the drive support AAM?

b) Is AAM activated?

c) To what value is the AAM set?

If a drive supports AAM, you can activate the feature and set the AAM value or deactivate AAM completely, if the drive is capable of doing so. Any changes you make will be remembered by the drive even after power off.

This program requires real DOS - it can't access the hardware from a DOS-Box or a command prompt within Windows. If you're using Win 9x/ME you can boot to DOS by pressing the key "F8" at startup. Windows NT/2000/XP users will need a DOS-Bootdisk.

The AAM technology was introduced around the end of 2000 to reduce the acoustic noise that occurs while reading and writing from or to an ATA hard disk. Basically this is achieved by moving the read/write head more slowly, which in turn leads to reduced performance of the hard drive. The ATA-specification allows AAM-Values from 128 to 254, where 128 is the quietest and 254 the fastest mode of operation. However this doesn't mean that a hard drive can operate at 127 different volume levels. The actual number of modes is left up to the disk manufacturer. It's possible that a drive operates in "quiet mode" from 128 to 190 and in "fast mode" from 191 to 254. Some disks can even only remember the two values 128 and 254 - you have to experiment a little to figure it out for your drive. If AAM can be deactivated is also up to the manufacturer, and so is the behavior of the drive when AAM is off (fast, quiet or in between).

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