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Fixboot

The Fixboot is a Recovery Console command that writes a partition boot sector to a system partition that you can specify.

Boot Sectors

Boot sector is a sector on a hard drive or data storage device that contains code for booting a program stored on some other part of the storage media.  The computer BIOS can be set to select any of several boot devices and then copies the first sector from the boot device to address location 0×7C00.

Different kinds of boot sectors can be encountered on computer hard disks and other storage devices.  A master boot record (MBR) is the first sector of a data storage device that has been partitioned. The MBR sector contains code to locate the active partition and start its Volume Boot Record.

Volume Boot Record (VBR)

A volume boot record is the first sector of a data storage device that has not been partitioned.  It contains code to load and start an operating system installed on that device or within that partition.

Valid boot sectors have a two-byte hex word 0xAA55, called the boot sector signature and must exist at the end of the sector.  If the signature is not present either the BIOS or MBR code will report an error message and halt any OS startup process.

The computer BIOS does not distinguish between VBR and MBR. The firmware will only load and runs the first sector of the storage device. floppy devices or USB flash drives will use a VBR to boot. Hard drives use an MBR. The MBR has the partitioning information and will start the VBR which will load the operating system.

Boot Sector Viruses

Since the code in the boot sector is first executed automatically the boot sectors have been targets for computer viruses. As a warning computer BIOS now have included a feature to prevent writing over the boot sectors without user permission.

FIXMBR

FIXMBR is a Recovery Console command that writes a new MBR to the first sector of a hard drive.  This command can be used to correct a corrupted or infected MBR.  The fixboot command write the partition boot sector.

The FIXMBR website has some additional articles you might find useful.

November 18th, 2009 | Tags: , , , , , , , , , | Category: Fixboot | Leave a comment

Fdisk

The Fdisk is a DOS command available when you boot your computer to DOS and type in fdisk at the command prompt.  Using fdisk you can partition a hard drive and set active the boot partition.  You are limited to only one primary partition using the DOS fdisk command and four partitions.  This is because DOS will destroy itself  if it sees more than one primary partition.  Microsoft therefore limited fdisk to creating only one primary partition.  However you can create an extended partition and within the extended partition create multiple logical drives.  I have created some more resources for running the fdisk command and creating partitions.  You can view some additional Fdisk resources at the following sites:  Fdisk YouTube video and Fdisk article document.

Another good utility for partitioning a hard drive is GParted a free Open Source utility that runs on Linux.  I like to run GParted from a Live CD Linux distribution using Insert.  This allows me to have complete control over the computer by running my operating system from just the CDROM and allowing me access to the hard drive.  You could also use Insert to recover files on a non functioning hard drive.  Insert then becomes a valuable recovery tool and maintenance tool.  For more information concerning GParted I have a GParted HuPage that you can view.

FIXMBR

The FIXMBR website has some additional articles you might find useful.

October 11th, 2009 | Tags: , , , , , , , , | Category: Fdisk | One comment