IBM Deskstar 120 GXP, Specifications

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9.16 Automatic Acoustic Management feature set (AAM)
This feature set allows the host to select an acoustic management level. The acoustic management level
may range from the lowest acoustic emanation setting of 01h to the maximum performance level of FEh.
Device performance and acoustic emanation may increase with increasing acoustic management levels.
The acoustic management levels may contain discrete bands. Automatic Acoustic Management levels 80h
and higher do not permit the device to enter Standby mode as a result of the Automatic Acoustic
Management algorithm. The Automatic Acoustic Management feature set uses the following functions:
1. A SET FEATURES subcommand to enable Automatic Acoustic Management
2. A SET FEATURES subcommand to disable Automatic Acoustic Management
Advanced Power Management, Automatic Acoustic Management, and the Standby timer setting are
independent functions. The device shall enter Standby mode if any of the following are true:
1. The Standby timer has been set and times out.
2. Automatic Power Management is enabled and the associated algorithm indicates that the Standby
mode should be entered to save power.
3. Automatic Acoustic Management is enabled and the associated algorithm indicates that the
Standby mode should be entered to reduce acoustical emanations.
The IDENTIFY DEVICE response word 83, bit 9 indicates that Automatic Acoustic Management feature is
supported if set. Word 86, bit 9 indicates that Automatic Acoustic Management is enabled if set. Word 94,
bits 7-0s contains the current Automatic Acoustic Management level if Automatic Acoustic Management is
enabled, and bits 8-15 contain the Vendor's recommended AAM level.
9.17 Address Offset Feature
Computer systems perform initial code loading (booting) by reading from a predefined address on a drive.
To allow an alternate bootable operating system to exist in a system reserved area on a drive, this feature
provides a Set Features function to temporarily offset the drive address space. The offset address space
wraps around so that the entire drive address space remains addressable in offset mode. Max LBA in
offset mode is set to the end of the system reserved area to protect the data in the user area when
operating in offset mode. The Max LBA can be changed by an Set Max Address command to access the
user area. If the native MAX LBA is set, the whole user area can be accessed. But any commands which
access sectors across the original native maximum LBA are rejected with error, even if this protection is
removed by an Set Max Address command.
9.17.1 Enable/Disable Address Offset Mode
The Set Features subcommand code 09h Enable Address Offset Mode offsets address Cylinder 0, Head
0, Sector 1, LBA 0, to the start of the nonvolatile protected area established using the Set Max Address
command. The offset condition is cleared by Subcommand 89h Disable Address Offset Mode, Hardware
reset, or Power on Reset. If Reverting to Power on Defaults has been enabled by Set Features command,
it is cleared by Soft reset as well. Upon entering offset mode the capacity of the drive returned in the
Identify Device data is the size of the former protected area. A subsequent Set Max Address command
with the address returned by Read Max Address command allows access to the entire drive. Addresses
wrap so the entire drive remains addressable.
If a nonvolatile protected area has not been established before the device receives a Set Features Enable
Address Offset Mode command, the command fails with Abort error status.
Deskstar 120GXP hard disk drive specifications
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