[ale] help with LDE [linux disk editor]

Greg Freemyer greg.freemyer at gmail.com
Tue Nov 28 17:43:27 EST 2006 

Courtney,

Did you ever get it resolved.

If not, reading "man gpart" is worth your time.

And I think it has a -W arg to actually update the partition table in the MBR.

Having that should allow you to mount the drives etc, but the drive
itself will not be bootable.

If you want to boot off of the drive you have to install some boot
loader code into the MBR.  Personally I use grub  (via grub-install
IIRC).

Hope you got it working
Greg

On 11/26/06, Courtney Thomas <courtneycthomas at bellsouth.net> wrote:
> Greg,
>
> Thank you for the edifying commentary. I need all the help I can get  :-)
>
> Based on your description, I have no MBR, apparently.
>
> But, based on a gpart scan, it has seemingly found the 3 primary partitions,
> /, /boot & /var; plus the swap segment.
>
> Incidentally, if it would be helpful in deciphering my comments, I'd be glad
> to
> forward the gpart scan file as an attachment.
>
> Fortunately, I do have the exact begin/end sizes for all partitions before
> this
> implosion, so I do have a numerically clear and accurate picture of the
> former
> layout, which I'd also be pleased to relay should you be willing to look it
> over.
>
> I may not have mentioned that the disk has Debian installed, using ext2fs.
>
> Cordially,
>
> Courtney
>
>
>
>
> ----- Original Message -----
> From: "Greg Freemyer" <greg.freemyer at gmail.com>
> To: "Atlanta Linux Enthusiasts" <ale at ale.org>
> Sent: Sunday, November 26, 2006 2:40 PM
> Subject: Re: [ale] help with LDE [linux disk editor]
>
>
> > Courtney,
> >
> > I'm still unsure what your issue is.
> >
> > The Master Boot Record (MBR) (I think thats the right name) is
> > maintained in sector 0 of the entire drive.
> >
> > In the old Cylinder/Head/Sector addressing scheme it was Cyl 0, Head
> > 0, Sector 0.  In modern LBA terminology it is simply sector 0.  The
> > first partition traditionally starts at Cyl 0, Head 1, Sector 0.  With
> > most modern disks the internal drive electronics emulate a drive with
> > 63 sectors per head, so that works out to Sector 63 being the start of
> > the first partition.
> >
> > Anyway, I believe there is only one MBR per disk regardless of the
> > number of sectors.  With a standard Intel/Windows partition table a
> > small part of the MBR is used to hold the partition table.  I think
> > "man gpart" will tell you which bytes specifically hold the partition
> > table.
> >
> > If the partition table within the MBR becomes corrupt, then a tool
> > like gpart can be used to recreate it.
> >
> > Then for each filesystem there is a superblock.  The superblocks
> > reside within the partitions but the structure and layout is
> > filesystem dependent.  Some filesystems like XFS even maintain a
> > backup copy of the superblock.  Others like FAT32/NTFS don't call it a
> > superblock at all.
> >
> > Hope the helps with terminology as you read about and research your
> problem.
> > Greg
> >
> > On 11/26/06, Courtney Thomas <courtneycthomas at bellsouth.net> wrote:
> > > Thanks Greg, that's exactly, apparently, what I need, in that the
> superblock
> > > is seemingly gone.
> > >
> > > I'll try it.
> > >
> > > Sure will be glad when flashdisks are cheap and I never need to consider
> > > things that go round and round again  :-)
> > >
> > > Merry Christmas,
> > > Courtney
> > >
> > > ----- Original Message -----
> > > From: "Greg Freemyer" <greg.freemyer at gmail.com>
> > > To: "Atlanta Linux Enthusiasts" <ale at ale.org>
> > > Sent: Saturday, November 25, 2006 7:40 PM
> > > Subject: Re: [ale] help with LDE [linux disk editor]
> > >
> > >
> > > > Courtney,
> > > >
> > > > I've never used LDE, but I suspect it works at the partition level not
> > > > the disk level.
> > > >
> > > > If that is the case you need to try "lde /dev/hda1" to edit the first
> > > > primary partition on the disk.
> > > >
> > > > "fdisk -l /dev/hda" will tell you what partitions you have to choose
> from.
> > > >
> > > > If for some reason your partition table is destroyed, you may want to
> > > > look into gpart as a tool to recreate the partition table.
> > > >
> > > > Hope that helps
> > > > Greg
> > > >
> > > > On 11/25/06, Courtney Thomas <courtneycthomas at bellsouth.net> wrote:
> > > > > I'm tryin' to learn to use LDE and am experimenting with an old
> outta
> > > whack
> > > > > disk.
> > > > >
> > > > > When I...
> > > > >    lde /dev/hda
> > > > > the first screen comes up with an error screen, reporting....
> > > > >
> > > > >    root inode is not a dir
> > > > >    first block  (0) != normal first blk (1)
> > > > >    found ext2fs on device
> > > > >
> > > > >        inodes 252416
> > > > >        blocks 504000
> > > > >        firstdatazone 0 (N=1)
> > > > >        zonesize 4096
> > > > >        max size 1074791436
> > > > >
> > > > > 1-since root inode is not a dir, how do I convert it to a dir ?
> > > > >
> > > > > 2-what is the significance of the normal first block being 1 and
> this
> > > one's
> > > > > 0
> > > > >
> > > > > 3-what do you make of the numbers in the second block of data [5
> lines]
> > > ?
> > > > >
> > > > > 4-by root inode, does LDE mean the superblock or block 1, I've
> assumed
> > > the
> > > > > superblock ?
> > > > >
> > > > > I hope that if I can resuscitate this disk, then when I run into
> > > real/active
> > > > > disk calamities,
> > > > > that I might be able to recover. Any suggestions for further
> information
> > >  on
> > > > > use of this tool ?
> > > > >
> > > > > Thank you,
> > > > > Courtney
> > > > >
> > > > > _______________________________________________
> > > > > Ale mailing list
> > > > > Ale at ale.org
> > > > > http://www.ale.org/mailman/listinfo/ale
> > > > >
> > > >
> > > >
> > > > --
> > > > Greg Freemyer
> > > > The Norcross Group
> > > > Forensics for the 21st Century
> > > > _______________________________________________
> > > > Ale mailing list
> > > > Ale at ale.org
> > > > http://www.ale.org/mailman/listinfo/ale
> > >
> > > _______________________________________________
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> > > http://www.ale.org/mailman/listinfo/ale
> > >
> >
> >
> > --
> > Greg Freemyer
> > The Norcross Group
> > Forensics for the 21st Century
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org
> > http://www.ale.org/mailman/listinfo/ale
>
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-- 
Greg Freemyer
The Norcross Group
Forensics for the 21st Century

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