1 Topic by eggeggegg

  • eggeggegg
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  • Registered: 2007-07-07
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Topic: Problem with disk geometry?

Hello, this isn't necessarily to do with Gparted but I thought someone might be able to help...
There seems to be something very wrong with my partition table / MBR / whatever.
Just recently I have started to get a lot of file system errors although there are definitely not bad sectors as confirmed by Maxtor diagnostics. Partition magic 8 reports that the drive is BAD and gives this error:

Error #106: Partition didn't begin on head boundary.
  ucBeginSector expected to be 1, not 7.

When I go to the recovery console in XP and do 'fixmbr' it says there is something wrong with the MBR but doesn't fix it.

I tried something called Partition Table Doctor which said there was a problem but the 'fix' seemed to involve deleting one the partitions which wasn't a great help, and it was a demo anyway.

Gparted finds errors on the filesystem but won't fix them.

I have tried to use TestDisk but it doesn't make a lot of sense. Strangely, it says the disc geometry is CHS 24792/255/63 but Maxtor diag says it is 395136/16/63, is this the cause? However I looked at the geometry of another (working) drive and testdisk values also didn't match the maxtor ones.

This is what PartitionInfo says:

===========================================================================================================
Disk Geometry Information for Disk 1:    24792 Cylinders,  255 Heads,  63 Sectors/Track
System              PartSect  # Boot BCyl Head Sect  FS    ECyl Head Sect    StartSect     NumSects
===========================================================================================================
                           0  0  80     0    1    1  07    1023  254   63           63   48,596,562
Info: End C,H,S values were large drive placeholders.
  Actual values are:
        0  0  80      0    1    1  07   3024  254   63        63  48596562
                           0  1  00  1023    0    7  07    1023  254   63   48,596,631  349,686,849
Info: Begin C,H,S values were large drive placeholders.
Info: End C,H,S values were large drive placeholders.
  Actual values are:
        0  1  00   3025    0    7  07  24791  254   63  48596631 349686849
Error #106: Partition didn't begin on head boundary.
  ucBeginSector expected to be 1, not 7.

Any help is very much appreciated!

2 Reply by class413

  • class413
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  • Registered: 2007-05-25
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Re: Problem with disk geometry?

I think this Cylinder/Head/Sector issue is rather obsolete, because these number are not real in the actual computing. There is not the same number of cylinders in any disk track. It remains from the time of the old disks of some 10s or a few 100s of MB. I thing all disks above 500MB big must be shown as LBA (or auto) in the BIOS.

The disk geometry is included in some place in the master boot sector, but modern operating systems (including linux and windows) don't use this info to communicate with the disk. They use other info coming from the disk firmware. Even the partitions don't have to start and end to "Cylinders" boundaries. Did you change anything to your partitions before these system errors begun to appear? How the actual partitions were made?

I heard many times that a space (unallocated) of 8MB must be between windows partitions, but some people affirm that even this is not needed. I think you must search first to the windows side, as your system worked well for long. Often a bad driver or a defective hardware part can cause strange problems. If the partition boundaries are really a problem, you could try to slightly resize the partitions (shrink them just a few MB). This readjusts the partition boundaries.

*** It is highly recommended to backup any important files before doing resize/move operations. ***