Identify Device Data; Exceptions In Address Offset Mode; Figure 75. Device Address Map Before And After Set Feature - IBM IC35L020 - Deskstar 20 GB Hard Drive Specifications

Disable Address Offset Feature removes the address offset and sets the size of the drive reported by the
Identify Device command back to the size specified in the last nonvolatile Set Max Address command.
Before Enable Address Offset Mode
A reserved area has been created using a non-volatile Set Max command.
Accessible
(User Area)
LBA 0
After Enable Address Offset Mode
After Set Max Address Command using the Value Returned by Read Max Address
Any commands which access sectors across the LBA M–R are aborted with error.

Figure 75. Device address map before and after Set Feature

13.17.2 Identify Device Data

Identify Device data word 83 bit 7 indicates the device supports the Address Offset Feature.
Identify Device data word 86 bit 7 indicates the device is in Address Offset mode.

13.17.3 Exceptions in Address Offset Mode

Any commands which access sectors across the original native maximum LBA are rejected with error
even if the access protection is removed by an Set Max Address command.
The Read Look Ahead operation is not carried out even when enabled by Set Feature command.
Non-Accessible
(Sytem reserved
area)
LBA R
Accessible
(System reserved
area)
LBA 0
Accessible
(System reserved
area)
LBA 0
Deskstar 60 GXP Hard disk drive specification
94
LBA M
Non-Accessible
(User area)
LBA M–R
Accessible
(User area)
LBA M–R
LBA M
LBA M