[TriLUG] OT: Dell desktop, recovering boot and partition info

Joseph Mack NA3T jmack at wm7d.net
Mon Aug 31 20:51:07 EDT 2009

I have a 40G disk from a friend of a friend. The machine 
crashed in normal use (whatever that means), and the machine 
wouldn't reboot. The disk dd's just fine so presumably 
there's no fundamental problem moving heads and reading etc.

The disk has no valid partition table and appears to he 
255heads (specs say 16), and 63 sectors so presumably this 
part of the first sector has been zeroed out. fdisk -l tells 
me the disk is 797G (rather than 40G and I dd'ed the whole 
797G when checking the disk, it really thinks it has 797G).

I haven't been able to get much joy out of trying to mount 
the 797G copy of the disk, so reluctantly I'm working 
directly on the disk. I also don't have a spare disk large 
enough to make a bitwise copy.

I can mount two partitions (mount with offset incremented in 
a loop)

part 1 vfat of 48M

about 100 empty blocks

part 2 ntfs of 35G

the vfat partition has command.com, mydos.sys, io.sys (DOS 
boot files), a bunch of *.mdm files (no idea), a file 
delldiag.exe, another dellboot.exe, a directory called 
"dell", with a bat file to reboot the machine (and write a 
logfile) and a few other files.

the ntfs partition looks like normal windows.

Anyone know what the small vfat partition is for? When you 
boot, do you get a choice of booting into the vfat partition 
or booting windows or is windows booted through the vfat 
partition (ie can I ignore the vfat partition?)

Presumably I can write a partition table at the start of the 
disk to match the partitions I've found. Do I just copy a 
windows boot loader into the front of the first sector, make 
the 2nd partition active and let it boot?


Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!

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