another "partition accident" problem

[mr.MikyMaus]

I have made a little but almost fatal mistake : mkfs.ext2 /dev/hda
I stopped the formating reflexively but partition table any maybe some data at the beginning of the disk were destroyed. Now what? I have not rebooted the coputer since and I still have access to all important data. I do not care about some gigabyte at the beginning of the disk.
The original partition table image is stored somewhere in RAM. All I need is to get it back where it belongs. But I do not know how...Does anyone have some experience with such thing or at least an idea?

[drakebasher]

Does anyone have some experience with such thing or at least an idea?

No and yes. I have read that on certain types of volumes, there are multiple copies of the partition table at certain known locations and if I recall correctly, it is possible to call for one of the alternate tables to be used by passing a parameter to the kernel. I can't recall the source, but I'll try. Meanwhile, this may help:

From Linux Documentation Project:

• 3.2.2. Linux own info and other hacks
  3.2.2.1. Kernel
  
  If you just destroyed your own partition table, but have not rebooted Linux : Don't reboot! You can still retrieve the partition information stored in the Kernel:
  
  cat /proc/partitions gives
  
  major minor #blocks name
  3 0 19535040 hda
  3 1 2096451 hda1
  3 2 4980150 hda2
  3 3 1 hda3 <----- this marks an extended partition
  3 5 4980118 hda5
  3 6 4972086 hda6