Billy Davis wrote:
We are running Centos 5.6. All was fine until yesterday. I attempted to tar a 14KB work file to a USB floppy (/dev/sdb) for transport to another server. Unfortunately, I keyed in 'tar cvf /dev/sda filename' instead of 'tar cvf /dev/sdb filename'. /dev/sda is our main (boot/root/apps) scsi hard drive. I realized my mistake, but it was too late. The system is still powered up and running, but I am sure that I have overlaid (and trashed) the mbr and the disk directory map.
<snip>
I suspect that when I power the system down, it will not reboot. I can
You have that right.
reinstall mbr and grub, but I don't have the original partition table start/end values. Since the system is still running, it seems that the partition table must still be available to it from somewhere.
Is there any way to easily restore the partition table?
Easily? No (other than the grub-install /dev/sda part).
Sorry about your problem, but I appreciate the question: it led me to http://www.cromwell-intl.com/unix/linux-kernel-details.html, a fair bit of which was quite familiar, and other bits weren't. For example, cat /proc/partitions might give you a serious bit of the information you're looking for.
Hope that helps.
mark