I think that's just part of it...

Check out: http://support.microsoft.com/default.aspx?scid=kb;EN-US;q69013

MORE INFORMATION

What is the MBR? 
At the end of the ROM BIOS bootstrap routine, the BIOS reads and executes
the first physical sector of the first floppy or hard disk on the system.
This first sector of the hard disk is called the master boot record (or
sometimes the partition table or master boot block). There is a small
program at the beginning of this sector of the hard disk. The partition
information, or partition table, is stored at the end of this sector. This
program uses the partition information to determine which partition is
bootable (usually the first primary DOS partition) and attempts to boot from
it. 

This program is written to the disk by the fdisk /mbr command and is usually
called the master boot record. During typical operation, Fdisk writes this
program to the disk only if there is no master boot record. 

NOTE : The fdisk /mbr command only re-writes the MBR on the system drive
(DISK-0) using BIOS calls. You cannot specify any other drive for the fdisk
/mbr command to operate on other than DISK-0. 
Why is the MBR Changed During Setup? 
During the installation of Microsoft MS-DOS Upgrade, Setup replaces the
master boot record on the hard disk with code to display a message similar
to: 
The MS-DOS 5.0 Setup was not completed. 
Insert the UNINSTALL #1 diskette in drive A. 
Press the ENTER key to continue. 
This message should be erased and the master boot code rewritten before
Setup is completed. If a problem occurs during Setup and you return to the
previous version of MS-DOS, Uninstal should also remove this message.
However, if Setup or Uninstal does not remove this message, or if the master
boot record becomes corrupted, a new master boot record can be written to
the disk using the following command: 
fdisk /mbr 
WARNINGS 
Do not use this command if any of the following conditions exists: 
The disk was partitioned using the Storage Dimensions SpeedStor utility with
its /bootall option. 


More than four partitions exist. 


Certain dual-boot programs are in use. 


The Storage Dimensions SpeedStor utility with the /bootall option redefines
the drive's physical parameters (cylinder, head, and sector). The /bootall
switch stores information about how the drive has been changed in an area of
the master boot record that MS-DOS does not use. The fdisk /mbr command
erases that information, making the disk unusable. 

Some older original equipment manufacturer (OEM) versions of MS-DOS and some
third-party partitioning utilities can create more than four partitions.
Additional partition information is commonly stored information on
partitions in an area that the fdisk /mbr command overwrites. 

Some dual-boot programs have a special MBR that asks you at startup which
operating system you want to use. The fdisk /mbr command erases this
program. Dual-boot systems that boot whichever partition is marked Active
are not affected by the fdisk /mbr command. 

For more information about partitioning, query on the following word in the
Microsoft Knowledge Base: 
partitioning 
The third-party products discussed in this article are manufactured by
vendors independent of Microsoft; we make no warranty, implied or otherwise,
regarding these products' performance or reliability. 




REFERENCES
More information on partitioning, disk organization, and the boot sequence
can also be found in Chapters 3 and 8 of the DOS Programmer's Reference by
Terry Dettmann, published by the QUE Corporation; Chapters 2 and 10 of
Advanced MS-DOS Programming by Ray Duncan, and article 3 of The MS-DOS
Encyclopedia , both published by Microsoft Press. 


-----Original Message-----
From: Edward Dekkers [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 08, 2002 7:09 PM
To: [EMAIL PROTECTED]
Subject: Re: System is hanging with 'LI' only showing


> Isn't it the MBR that contains the partition info?

I doubt it. when you re-write the MBR, you don't lose your partitions?





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