Boot Control

Please note: Boot Control is no longer actively developed. The current version was created early 1999; many of the statements in the documentation and on this page reflect the state of computer hardware from that period. Harddisks of multi-gigabyte size, commonly found now, were unusual then (if they even existed). New BIOS standards to deal with such large harddisks have evolved. Modern BIOSes have adapted to these standards. Boot Control hasn't. Unless you know what you're doing, Boot Control is probably only useful to you if you wish to use it on (to current standards) small harddisks.

This is the Boot Control home page. This page will show you what Boot Control is, and allow you to download it. It also provides a link to the documentation in several formats. The current version is V0.41, which is mainly a bugfix release. Changes in this version (from V0.4):

MBR's 5 to 8 could respond to illegal input (specifically, the arrow and function keys etc.) by leaving the MBR without an active partition. This in itself is not a problem (for the MBR software), but some BIOSes refuse to boot a harddisk without an active partition. These keys are now ignored.
A small screen coloring bug in the initial help screen is fixed.
The installation program now uses standard DOS I/O for its input, allowing input redirection for automated (re-)installs.

What is it?

Many operating systems are available for IBM PCs and compatibles. With computer hardware, including harddisk space, getting cheaper every day, many people want to install or try out many different operating systems. Every OS has its strong and its weak sides - why limit yourself? Unfortunately, managing multiple operating systems on one PC can be a bit complicated. As there are many different file systems in use, different OS' are often installed each in their own partition. A partition is a section of a harddisk that is treated as a completely separate unit. For example, if you have two FAT (the file system that DOS uses) partitions, each will be assigned its own drive letter.

Information on where on the harddisk these partitions reside is contained in the partition table in the Master Boot Record. This is the first sector of the harddisk. The partition table can contain (or rather, describe) up to four partitions. The MBR also contains some executable code. When the PC boots, it is loaded in memory, and executed. The code in the standard MS-DOS MBR checks which partition is marked active, and boots that partition (by loading its first sector to memory and executing it - this sector is called the boot sector).

The process of booting another OS therefore means: setting the active flag to the partition containing that OS, and rebooting. MS-DOS, for example, comes with the FDISK utility that allows you to do that. You can not decide at boot time which OS you like to load - you first have to boot whatever OS is currently marked active, use its FDISK utility to set the active flag to the partition you want to boot, and reboot. This isn't exactly convenient. It is also not possible, using the standard MS-DOS MBR software, to boot operating systems located on other drives than the first harddisk.

There are a few remedies for these problems. Some operating systems come with utilities that allow you to choose, at boot time, which partition to boot. To name some:

OS/2 comes with its boot manager. I have no personal experience with it, but apparently it gives you a menu at boot time of the installed operating systems, allowing you to pick whichever you want. One great disadvantage is that it requires a primary partition for itself, using up one of the four available slots in the partition table. I don't know if it can boot partitions on other drives.
Linux has LILO (Linux Loader) available. If you've installed Linux, you may already be using LILO. Unfortunately, to boot anything other than the default OS, you have to press one of the SHIFT, ALT or CTRL keys at boot time. Once you've done that, an undescriptive prompt asks you what to boot, and you have to type in the full name of the OS you want to boot. This is unpleasant, especially if you switch a lot between different operating systems (as I do). LILO can boot partitions anywhere, on any harddisk. (There are also programs that boot Linux from DOS (LoadLin). If you only want to run Linux and DOS, this may be worth considering).

Boot Control was designed to make boot time selection of the operating system to boot as easy as possible. From the documentation: "Boot Control is a set of alternative Master Boot Records, together with an installation program. The installation program replaces the current MBR with one of its own, which displays a small menu at boot time. The menu shows up to four (named) partitions, and lets you choose which one you want to boot. Some of the MBRs also allow you to boot other drives." A default partition or harddisk is highlighted, and will be booted after a configurable timeout. All you have to do to select an OS is type the number of the partition (or the letter of the drive) you want to boot, or ENTER or SPACE to boot the default. Currently, seven different MBRs are available to choose from, with different functionality.

Boot Control is work in progress. Most of the MBRs reflect my personal needs at some point - they may not reflect yours. Still, I've attempted to make them as universal as possible.

RTFM!

Please, before using Boot Control, carefully read the manual! Messing with your MBR is not something to do casually. Especially note that Boot Control is currently incompatible with software that supports large harddisks (> 504 MB) on older BIOSes, like EZ-Drive or Disk Manager. This software is also installed in the MBR, and overwriting it can make all your data inaccessible!

The documentation that comes with the Boot Control executables is mechanically converted from the HTML version. It contains all information the prettier versions have, and requires no special programs to read. It is, however, less suitable for printing. You may want to download one of the alternatives:

The DVI file. You can download the ZIPped version below. If you want to print out the documentation, this file, in combination with a LaTeX installation, will give the best results. It is formatted for A4 paper, but it should fit on letter paper too. (There are free versions of LaTeX available for most operating systems, including DOS).
The HTML formatted version, which consists of one single file. I have created the HTML version without any pictures, so people using text-mode browsers can read all information. In the future, a prettier version may also be available. If you want, you can download this to your system and use it off-line (a ZIPped version can also be downloaded below).

The ZIP files.

Download the executables (30222 bytes). This file contains the Boot Manager executable, the text version of the documentation, and a small utility to assist DOS users without a disk editor in creating multiple primary partitions.
Download the DVI file (31841 bytes). This is the LaTeX-generated documentation. It prints out very nicely if you have LaTeX installed.
Download the HTML file (22828 bytes). If you don't want to download the DVI file, you may want to download this one instead. It consists of one single file, and can be viewed offline with any web browser.

Money?

In gratitude of all the free software around, especially Linux, I've decided to make Boot Control free software. You can use it for whatever purpose you see it fit, and distribute it to anyone you want - under the express condition that you distribute the executables in their original archive file, including the documentation. Note, though, that Boot Control is copyrighted software. You are not allowed to sell this program to anyone else (although a reasonable distribution fee is acceptable). Also note that I can't take responsibility for any loss of data or other disasters caused by or related to the use of Boot Control.

Gertjan Klein.

Mail me if you have comments, questions, suggestions, whatever.