Sponsoring website: Emergency Boot CD

All the Details of many
versions of both
and OS Boot Records

These pages will probably always be in a state of flux (change) as we keep gathering new data for Boot Records, filling in Assembly code comments and adding important topics related to booting up your box (computer)!

Personalized Data Recovery help via E-Mail (for a reasonable fee).

Index to MBR and OS Boot Records (with COLOR highlighting):

Start Here: Disk Drive Terminology

As either a review or an introduction (for those who need definitions and explanations of the terms used), we suggest that everyone read or at least glance over: Disk Drive Terminology [covers both Hard and Floppy Disk drives]. These terminology pages include useful details (even experienced techs should read them!) such as: How do you calculate the exact capacity of a floppy disk or hard drive?, Why do some utilities show less drive capacity than what's printed on the HDD?, What do MiB and GiB mean? and Do you know that partitioning a drive on a computer with a BIOS made earlier than 1999 will most likely waste drive space on an archaic structure known as a Test or Diagnostic Cylinder?

Understanding Partitions and Partition Tables
-- Completely New REVISION; now 3 pages long... still unfinished, but very useful!

How many Sectors are on a Hard Drive? -- Contains useful tables for picturing the contents of your hard drive.

Some Miscellaneous Topics:

An Introduction to Data Recovery.

How To Permanently Erase ALL the DATA On A Hard Disk -- without physically destroying your drive!

How to change your BOOT.INI Menus under Win2000/XP

HDD and OS Disk Limits: 32GB, 64GB, 137GB etc.!!!

6 to 64-bit Hex Numbers (and Basic Partition Table Limits)

Partition Magic writes "28 96 C4 17" to an HDD's 1st Track

55AAh is the Wrong Way to describe the Boot Signature on a PC
Explains why many have misunderstood how to refer to the byte sequence 55h followed by AAh on a PC: It's due to the little-endian architecture of PCs and incorrect usage in the documentation.

Free Software:

References. Links. Free Tools, Utilities and Boot Managers:
 MBR, Partition Table and Boot Record Tools and Links .

MBRs (Master Boot Records)

All about FDISK.EXE -- Covers all versions of Microsoft® FDISK.
(and many other OSs) have "fdisk" programs that are safer for your data than Microsoft's FDISK; read the next selection about how MS-FDISK can destroy some of your data!
NOTE: Under Windows™ 2000/XP, FDISK has been replaced by a variety of methods for partitioning (setting up the MBR on) your drives:
1) The install CD when setting up a new system,
2) The Disk Management "MMC Snap-In" program,
3) The Recovery Console's command: diskpart (found on install CDs),
4) The diskpart command under the Command Prompt of Windows™ XP; even more difficult to use than the Recovery Console version of diskpart! So, Disk Management is the best choice for most users! ]   You could, of course, still use an old Win98 Boot Diskette's FDISK program to create a FAT32 partition.

The Windows™ 7 and 8 GPT (GUID Partition Table) 'Protective' MBR and EFI Partition -- The MBR created by a running Windows™ 7 or 8 OS (Disk Management) when choosing to 'Initialize' (partition) a drive as GPT. The Partition Type identifier "EE".

The Windows™ 7 MBR -- The MBR created by a running Windows™ 7 OS (Disk Management) or its install DVD when installed on either a completely blank hard drive, or a disk with existing Windows OSs; includes a few details about the Windows 7 OS.

The Windows™ Vista MBR -- The MBR created by a running Windows™ Vista OS (Disk Management) or its install DVD when installed on either a completely blank hard drive, or a disk with existing Windows OSs; includes a few details about the Vista OS.

The Windows™ 2000/XP MBR -- The MBR created by a running Windows 2000 or XP OS (specifically Disk Management) when used to install a completely blank hard drive on your system; includes details about the Win 2k/XP Disk Signature bytes!

The Windows MBR for FAT32 -- The MBR created by FDISK from Windows 95B (or OSR2), Windows 98/98SE and even Windows ME.

The Standard MBR --- This is the Master Boot Record that's placed on the first sector of any hard disk partitioned by FDISK.EXE (or FDISK.COM) from all versions of MS-DOS back to MS-DOS 3.30 (including DOS 6.22 and MS-Windows 95 "A" also known as MS-DOS 7.0).

This is also the same as the Standard IPL (or MBR) code used by the Ranish Partition Manager, TestDisk (before version 5.7) and some boot managers when there's a problem that requires the MBR code to be written again.

Notes on DOS 3.30 and an early (1988) OEM version -- The Master Boot Record created by the NEC® (Revision 3) version of MS-DOS 3.30's FDISK was slightly different than that of all the other MS-DOS 3.30 MBRs (in order to allow it to have 8 Partition entries in its Partition Table). Some important points about DOS MBRs in general are also included here.

The Ranish MBR/Compact Boot Manager -- Single sector MBR replacement included with the Ranish Partition Manager. Preliminary Listing only.


The IBM® Personal Computer™ DOS 2.00 MBR and How Similar it is to the Standard MBR (of DOS 3.30)  --- The Master Boot Record created by IBM®'s DOS 2.00; showing each byte of code that's different from the Standard MBR.



OS Boot Records

All about SYS.COM - Shows details of all versions of Microsoft® SYS.COM which can be used to create both Hard Disk and Floppy Disk OS Boot Records.
Under the Windows™ 2000/XP OSs, Hard Disk Boot Records are created by:
1) The install process,
2) The OSs' Disk Management
"MMC Snap-In" program (which partitions and formats), or
3) The CMD Prompt command: format.
]  Again, out of the these three, the Disk Management window is the easiest way for most users to accomplish this for a new drive they attach to an existing system.

1) The Basics: Floppy Disk Boot Records

MSWIN4.1 (Windows 98) Floppy Disk Boot Record
For Booting the underlying MS-DOS 7.1 of the Windows 98 Operating Systems from a Floppy Diskette. Preliminary Listing.

MS-DOS 5.0 Floppy Disk Boot Record -- For Booting the MS-DOS 5.0 to 6.22 Operating Systems from a floppy diskette.
Preliminary Listing.


The IBM® Personal Computer™ DOS 1.10 Boot Record
IBM's Personal Computer™ DOS 1.10.
These pages include facts about IBM's first International DOS version.

The IBM® Personal Computer™ DOS 1.00 Boot Record
IBM's Personal Computer™ DOS 1.00.
These pages include many other fascinating facts about the original PC's software.

2) Hard Disk OS Boot Records

The Windows 7 (NTFS) Boot Record Sector - The Win 7 (NT5.x?) Boot Record sector; except for the new code bytes (11 of them), it's rather similar to the Windows Vista VBR. It slightly refines testing for TPM 1.2, and continues to use the Vista BOOTMGR; again, it's structure is similar to the earlier NTFS Boot Records.

The Vista (NTFS) Boot Record Sector - The Windows Vista (NT5.x?) Boot Record sector; except for the new code (which also tests for TPM 1.2) and its tests for BOOTMGR, it's quite similar in structure to earlier NTFS Boot Records.

The NTFS Boot Record: Boot Sector - The Windows 2000 (NT5.0) and XP (NT5.1) Boot Record; including the NTFS BPB (BIOS Parameter Block). Link to "The Disk Editor View page" to view the Record as it would be seen in a disk editor.

The NTFS Boot Record: Bootstrap Code - The Windows 2000 (NT5.0) and XP (NT5.1) "Bootstrap" Sectors. . . which we refer to as the NTLDR Section of the NTFS Boot Record Preliminary Listing !

The FAT32 Boot Record under Windows™ 2000 or XP - The VBR created by Windows™ 2000/XP/2003 for a FAT32 partition, or what your old Windows 9x/Me VBRs (see MSWIN4.1 VBR) in the first partition of the first drive will be changed into when installing Win 2000/XP on that system.

MSWIN4.1 Boot Record - For the Windows 95B, 98 and 98SE and ME OS (or FAT32) Boot Records; including the BPB (BIOS Parameter Block).

Boot Managers (MBRs)

LILO (Linux Loader) Boot Manager's MBR --  This used to be the only Boot Manager for the Linux OS, and it is still the best choice for many Linux projects such as a Linux Boot Disk Rescue System.

GRUB - The GRand Unified Boot Manager! --  This one is now the default Boot Manager for some distros such as Red Hat. You may even consider using this Boot Manager for Microsoft OSs (after installing a small Linux /boot partition for the GRUB executable and support files); this is how The Starman runs his own multi-boot systems.

The Windows™ 2000/XP/2003 BOOT.INI Menu system
This is related to various system files, such as NTLDR, which may even appear in a Windows 98/ME partition if you install Win XP/2000/2003 onto the same computer!


Confused? Send me an e-mail if you have a specific question about the MBR or other Boot Records...


Updated: June 7, 2007; February 25, 2009; August 16, 2009; March 11, 2011; March 30, 2012.
Last Update: January 7, 2013.

You can write to us here: contact form
(opens in a new window).

The Starman's FREE TOOLS Page

The Starman's Realm Index Page