Inside the Dell PC Restore Partition

An Exploration by Dan Goodell
Refreshing the Reference Partition Table

The partition table resides in physical sector 0 of the hard disk. The reference partition table resides in sector 18 of the DSR partition. Refreshing the reference table means copying the partition table to the reference to make sure both copies are the same.

Opening a physical sector
Use PTS Disk Editor (de.exe) or a similar utility to copy the partition table. Boot from a DOS boot disk and launch de.exe. On the left side of the opening screen, choose to select from Physical devices, then on the right side select your hard disk.
Use the disk editor's Block Mark/Copy/Paste features
The display opens with the first sector on the hard disk--cylinder 0, head 0, sector 1. This is alternatively known as Absolute sector 0. Sectors normally are numbered starting with 1, but Absolute sectors (aka, LBA sectors) are counted from 0.

Use the disk editor's functions to mark a block of bytes, copy the block, and later paste the copy in the new location. These functions are all available from the editor's drop-down menus.
The partition table is shown blocked here
The partition table is in the first sector, and consists of 64 bytes from offset 01BE-01FDh.

Pressing the Tab key allows you to alternate between editing the raw bytes on the left side, or the ASCII translations on the right side.

Press Tab so the cursor is on the left-side part of the display, then move the cursor down to the start of the partition table at byte 01BE.

Use the menu option to Mark a block, then move the cursor to the end of the partition table, highlighting the block of bytes.

Use the menu option to Copy the block.
Scrolling down to sector 18 of the DSR partition
Use the menu option to open a new Window, but this time select Partitions, and open the third partition. This should be the DSR partition, and should be identifiable by the 'DellRestore' label (see Fixing PBR Label Alerts). If you have previously determined that the fourth partition is your DSR partition, then open the fourth partition instead of the third.

Scroll down to sector 18. This sector usually contains data that appears very similar to Absolute sector 0, and the sectors on either side (sectors 17 and 19) are often empty (filled with zeroes).

In sector 18, move the cursor to the start of the reference partition table--byte 01BE. Use the menu option to Paste the previously copied block from Absolute sector 0 to this corresponding location in sector 18 of the third partition.

When leaving the sector, you will be prompted to save the changes.

author: Dan Goodell

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