MBR (Master Boot Record, at LBA 0) and track 0 (LBA 0-62)

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MBR (Master Boot Record, at LBA 0) and track 0 (LBA 0-62)

  • I was wondering if someone out there with a functioning Dimension 8400 is kind enough to send me a dump of his/her hard drive track 0 (LBA 0-62)?
     
    I accidentally wiped my MBR (at LBA 0 of a hard drive) with the "Create a new RAID volume" option in BIOS, and was unable to boot from my Dimension 8400.  I used a MBR recovery tool to help me get back to a working MBR.  A nice tool that dumps out a template MBR, suggests for entries to be entered into the partition table in the MBR by searching for partition "signatures" on the entire disk.
     
    I can now boot to Windows XP (at partiton 1).  But, still unable to boot to the Dell Utility Partition (at partion 0) from the BIOS menu.   With the "Disk Editor" function of the recovery tool, I found I might have overwritten LBA 9 and 10 via the "back up MBR to a spare sector" function of the tool.  I found the Servie Tag of my 8400 was stored at LBA 11.  This led me to suspect I might have overwritten LBA 9 and 10, because they immediately precede LBA 11 (where the Service Tag is stored).
     
    Therefore, I am asking for a dump of track 0 (LBA 0 to 62) of a functioning 8400.   Except the Service Tag, I don't think there's any personal information on track 0.   If someone is kind enough to help, I will provide instructions on how to dump track 0 and how to erase the Service Tag in the dump.
    Thanks.
     
  • You might want to copy your post in the Dimension - Hard Drive forum as well.  The BIOS forum has a rather limited audience as compared to the more popular hard drive forum. 
  • tmcnospam-dell,

    I don't have an 8400, but I don't believe there should be anything 8400-specific in track 0.  The following should apply to all models.  (BTW, are you saying you're using RAID or not using RAID?)

    Only LBA 0 should matter, and there shouldn't be anything of consequence in LBA 1-62.  I've occasionally seen garbage in 1-62, but that was not relevant to the boot process.  Sometimes there will be junk in one or more middle sectors left there by other programs--often copy-protection schemes, but that wouldn't come into play until you try to use that particular program.  Ghost, including Dell's PC-Restore variation, will leave junk in LBA 62, but that's non-essential (everything still works if you wipe LBA 62 clean).  And the service tag is burned into the bios, not the hard disk.  (Perhaps some program is including your service tag as part of their copy-protection scheme?)

    IOW, the disk and Windows should still boot fine with LBA 1-62 completely zeroed out.  AFAIK, Dell's boot sequence does not look for anything there.  The DellUtility partition is booted by the bios, not any special boot code hidden on track 0--see www.goodells.net/dellutility for details.  The bios looks for a 'DE'-type partition in the partition table, so I wonder if perhaps you haven't reconstructed your partition table correctly.  Are you sure you found all partitions?  What about the DellUtility and DellRestore partitions--did you erase either, or should both of those still be intact on the disk?

    Dan Goodell

     

  • Dan, (dg1621)

    Thanks a lot for the info. I changed the Partition Type to DE and it did boot to the utility partion. I'm now searching for the Restore Partition which I might have missed during the MBR reconstruction process.

    But I suspect there's a restore partition on my 8400. Before the crash, XP reported a disc size of 149GB. When I reconstructed the Partition Table, I made the XP partition all the way to the end of the drive, i.e. the maximum LBA the drive can support. The size reported by XP is still 149GB. In addition, if we assume XP uses the unit of GB in the "binary sense", i.e. 1GB=2^30 bytes, not 1GB=10^9 bytes, then 149GB (binary) is about 160BG (decimal), which is exactly the advertised size of the hard drive.

    That the MBR was wiped arose from a series of difficulties that I encountered during the process of replacing a failed drive in the RAID 1 configuration. I finally resorted the "Create a new RAID volume" option in BIOS (by hitting ctrl-I). This piece of BIOS code for RAID provided by Intel is simply a lousy one. It wiped my MBR. I just wondered why the heck the creation of a RAID volume would have to erase the most important sector of a hard drive???
  • "But I suspect there's a restore partition on my 8400. Before the crash, XP reported a disc size of 149GB ... if we assume XP uses the unit of GB in the "binary sense", ... then 149GB (binary) is about 160BG (decimal), which is exactly the advertised size of the hard drive."

    I think your assumption is correct, so it sounds like there might not have been a restore partition previously.  You might try a diagnostic tool like findpart (www.partitionsupport.com) to see if it finds anything that looks like a fat32 partition near the end of the disk.

     

  • Dan,

    Thanks for the info. Findpart confirmed that there was no partition at the end of the disk. But Dell didn't ship a OS installation CD or recovery CD with the 8400.