[NTLUG:Discuss] Full system backup-restore for Desktop PC

[Ralph Green, Jr.]

Howdy,
  This issue has nothing to do with the BIOS. It is a matter of how the
disk drive is organized.  I don't have those 40 gig drives here, so I'll
have to make up some numbers to illustrate.
  Drive a;  123 sectors per track
            4 heads
            1000 tracks

  Drive b:  55 sectors per track.
            18 heads
            500 tracks

  Both drives will have about the same capacity, but they are organized
differently.  And while these are made up numbers, they are very
representative of actual differences in drives.  No cheap IDE drive will
have 18 read heads, but the translation that goes on in the drive makes
them look like they do.  And this kind of difference makes a simple dd
backup and restore fail between these two drives.
  If the restored disk were laid out similarly, but just a little too
small or two big, then you are often fine.  I agree with your last line.
Test the backup and be sure.
  My experience with this problem is about a year old now.  Maybe
something has happened to make it better.  Let me know if you think that
is true.
Good day,
Ralph


On Tue, 2005-06-28 at 00:26 -0500, brian at pongonova.net wrote:
> Ralph--
> 
> Not always true...the Linux kernel doesn't really care about disk
> geometries as reported by the BIOS.  Since you're backing up the
> entire device, the partitions are backed up (and restored) as well.
> We've copied images to/from different disks with no problems. 
> 
> Still, you bring up a good point:  Always test your backups *before*
> you need them!