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
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.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:.)
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.