Inside the Dell PC Restore Partition

An Exploration by Dan Goodell
The DOS-Type DSR Partition

A DOS version of a DSR partition serves one purpose: to wipe the XP partition and replace it with a copy of the original, "as-shipped" contents of the XP partition. (See here for a few screen shots from a DOS-type DSR partition.)

The restore operation is designed to proceed with minimal user interaction. In order for this to happen, the automated routine is going to make certain presumptions about the partition layout and contents. To avoid potentially disastrous pitfalls, the DSR system checks the system before proceeding with the restore operation.


How the DSR System Checks for Partition Changes
After the Dell MBR boots a DSR partition as drive C:, the autoexec.bat file runs dsrcheck.exe to examine the disk's partition layout. If things are not as it expects, the restore process is aborted.

Otherwise, DSRcheck restores the normal partition-type bytes and active flag that were changed by Ctrl+F11, and the restore process continues.


Restoring the Ghost Image (DSR-DOS)
If the hard disk passes DSRcheck's scrutiny, the autoexec.bat file launches the script file c:\bat\recover.bat to automatically run c:\bin\recover.exe and restore the Ghost image file, c:\img\fi.gho, to the disk's second partition.


"Resealing" the System
To return the computer to its "as new", sealed state, autoexec.bat next launches the command "c:\bin\dsrreset  run" to change the active partition to the first partition, and temporarily mount it as drive D:. It then copies d:\config.bts to d:\config.sys and any existing autoexec.bat file is deleted.    (Note to reader: When a Utility partition boots it sees itself as drive C:, but to the DSR system the Utility partition appears as drive D:.)

Finishing Up
Finally, autoexec.bat reboots the system. Since the system has been returned to its sealed state, it will start with the Dell EULA and Service Tag screens.


author: Dan Goodell

Back