after I lost my hard drive partition table

It was heart breaking when I noticed that an operation under windows totally ruin my hard drive. I was resizing the partitions, which was done by partition manager under windows, and I just fixed all the errors produced by this software, using grml linux iso. After I successfully logined windows. I was happy that time. I deleted an un-wanted partition in windows with its self-contained tool (control panel - administration tools - computer manager - disk manager), which resulted in the tragedy - I lost my hard drive logical partition table

... google ... google ... grml ... grml ... finally I have a solution to fix the problem

Essential tools: grml live CD - many necessary console tools to handle most of the work; gparted live CD - a much better resizing package, no more partition magic/manager, also fix the 240/255 error later; clonezilla live CD - similar as ghost, but free and open, very handy. (There is a live CD has both gparted and clonezilla, even better.)

The life saving software is TestDisk. The same team also produced PhotoRec, which I used before to help a labmate recover shift-delete images in windows successfully. The key here is go to setting and adjust the head/cylinder number. The default 255 not work for me. I changed to 240, and worked great! All my partitions showed up and I have the system happily running again. The knowledge behind this software is superblock. Hard drive are grouped into cylinder, and each cylinder is called a block. Every partition start with a superblock, which has all the information, such as size, format, etc, about this partition. But usually, the system has to use a partition table to directly access the superblock. Broke partition table only means that the map is gone, but all the data are still there. It is the matter to find them again, or to re-draw the map. TestDisk scans the hard drive block by block to find the superblock and reconstitute the partition table. Before I googled out this software. I was stupidly using ntfsresize and ext2resize and manually hunting the superblock, which is pain and inefficacy! The head/cylinder number I mentioned above is the definition of a block in your specific hard drive, represented by how many heads in one block/cylinder, which should be 255 in standard.

So, in summary, my problem is that I lost the "map" of my hard drive - the partition table. I solved it by using TestDisk, set the right number and rebuild the map! After that, gparted live CD takes over all the remaining adjustments ......

Two mistakes I had today and I will definitely avoid later.
1, Never resize any partition, especially ext2/3 format partition, in windows using partition manager.
2, never delete a ext2/3 format partition using windows self-contained tool.

One mistake I did not have today: never do any resize/move/format partition operation after the partition table is gone. Lose the partition table only means the map is gone. But the treasure is still there and the superblocks are the hints! Good luck.

Previous: How to "select" and generate locales on Ubuntu
Next: correct /etc/hosts and video setting for faster gutsy login