boot.asm

The boot.asm program was designed and written to be an easier method of using and installing the popular loader.asmcode. It is a simple program which gets linked with the loader object module to become a DOS executable file that installs the loader on either the A: or B: floppy disk drive.

Purpose

The purpose of this program is to allow a programmer to quickly create a bootable floppy disk which boots to his or her own code.

When you have built and installed the code, you will have created an executable file boot.exe (from boot.asm) which installs the boot loader on a floppy disk. Using this, you will create a floppy disk which contains a bootloader (loader.asm) and an operating system stub (beroset.asm) which you may then replace with your own code.

Building the Code

Tools

This code is designed for use with Borland's TASM only. When I built this code, I used

Borland MAKE version 5.2
Borland TASM version 4.0
Borland TLINK version 6.10
Microsoft Windows2000

The use of MAKE is optional, but using a Makefile makes things much simpler. If you use make, first make sure that make is either in your path or that you explicitly specify the path to it. Then make sure that where your tools are installed matches the makefile. I have TASM and TLINK installed in \bc\bin\ but if you use a different directory, you'll need to modify the Makefile accordingly. Finally, I wrote the files to the A: drive. You could also write it to the B: floppy by changing the makefile, but note that writing to the C: drive (or any hard drive) is not supported for two reasons: first, it could cause your computer to become unbootable if you ran it without knowing what you're doing, and second, to assure that you know what you're doing, you'll have to modify the code to do it. I strongly recommend that you get things working on a floppy disk first.

The Build Process

If you're using the Makefile, the build process is extremely simple. Just type "make install" and everything will automatically build and install, as long as you have boot.asm, loader.asm and beroset.asm all in the same subdirectory.

If you're not using make, you can simply run loaderkit.bat which will automatically build everything for you. Before you run the batch file, you should be sure you read it and understand what it's doing. It will overwrite the boot sector on your floppy disk without prompting, so please be sure that's what you want!

Technical Description

The boot.asm code is very simple, so I won't describe it here, but the interesting parts of the loader and operating system stub are described on this page.

Ed Beroset
Last modified: Fri Mar 9 17:25:13 2007