How to Create a Bootable
FreeDOS Floppy Disk

FreeDOS is a complete, free and fully compatible MS-DOS clone for Intel-compatible (i.e., x86) processors.

A clone is an operating system or application program that has functions and behavior similar to another program but which does not contain source code from that program. Source code is the original form in which a program is written by a human in a programming language; it is protected by copyright law, whereas the functionality of programs generally is not legally protected.

MS-DOS (Microsoft Disk Operating System), introduced by Microsoft in 1981, is a single-user, single-tasking computer operating system that has a command-line (i.e., text-only) interface. In spite of its very small size and relative simplicity, it is one of the most successful operating systems that has been developed to date, and it is still in widespread use, particularly by businesses.

The last stand-alone version of MS-DOS was version 6, which, unfortunately, is not Y2K (year 2000) compliant. Microsoft Windows 95 and some subsequent systems came bundled with MS-DOS version 7. However, that version is highly integrated with the GUI (graphical user interface) portion of the operating system, and thus it will not function effectively without access to the hard disk drive (HDD).

FreeDOS offers several important advantages over MS-DOS. It is Y2K-compliant and can be installed on a hard disk partition or on a single floppy disk. It can operate on a wide variety of x86 platforms, including new computers, old computers, DOS emulators and embedded systems.

Moreover, because it is free software (i.e., available to anyone at no cost for use for any desired purpose), it avoids the problems of royalty payments and licensing complexities that encumber proprietary software (i.e., commercial software) such as MS-DOS.

There are several uses for a bootable FreeDOS floppy. They include as a highly portable system for studying DOS, as a tool for repairing computers that use MS-DOS or some other Microsoft operating system and as a means for launching Windows XP without product activation.

The first step to installing FreeDOS on a floppy disk is to download the 755KB file from any of several sites on the Internet1. This version is based on FreeDOS Beta 9 (Release Candidate #5). Although there may still be gaps in the testing of it, it appears to work well.

After the compressed file has been downloaded, it must be unzipped (i.e., decompressed). This can be accomplished on Unix-like operating systems as well as on DOS systems with a command such as unzip, for example


It can also be accomplished on a Unix-like system using the gunzip command. Additionally, the file can be unzipped using a GUI-based compression/decompression program, such as WinZip on Microsoft Windows.

The decompressed package contains three files: the fdodin07.144 FreeDOS executable (i.e., runnable program), the optional diskcopy.exe program for copying the executable to a floppy disk and the readme.1st documentation.

A standard 1.44MB (megabyte) floppy disk is required. The floppy needs to be mounted (i.e., logically attached to the main filesystem) before the data can be copied to it using a Unix-like operating system. Mounting of floppy disks is, by default, generally not automatic (in contrast to Microsoft operating systems), but it can be easily accomplished by becoming root (i.e., the administrative user) with a command such as su (i.e., substitute user) and then using the mount command similar to the following:

mount /dev/fd0 /mnt/floppy

The FreeDOS data can be copied to the floppy using either a Unix-like operating system or MS-DOS. In the case of the former, the data can be copied using either the cat command or the dd command. For example, assuming that fdodin07.144 is in the current directory (i.e., the directory in which the user is currently working), cat would be used as follows:

cat fdodin07.144 > /dev/fd0

Likewise, dd would be used as follows:

dd if=fdodin07.144 of=/dev/fd0

The floppy could be created on a MS-DOS or FreeDOS system by using the diskcopy.exe program that is included in the downloaded file. For example, assuming that the downloaded file had been unzipped into a directory named ODIN on the C: drive, the following command could be used:

C:\ODIN>diskcopy fdodin07.144 A:

61 files and two directories (each with additional files) for a grand total of 157 files and 1,396KB are copied to the floppy. The largest file, at 65KB, is, the command interpreter or shell, which displays the DOS prompt and executes (i.e., runs) the commands typed in. This is followed by the text editor edit.exe at 61KB.

After copying, the new single-floppy version of FreeDOS is ready to use on almost any computer that has a floppy disk drive. The major exception is Macintosh computers, because they do not use Intel-compatible processors.

For some computers it might be necessary to change the boot sequence (i.e., the order in which the computer looks for a start-up disk) in the BIOS (basic operating system) so that the computer is configured with the floppy drive as the first boot device (or at least before the hard disk drive). The BIOS configuration screen is accessed by pressing some specified key when the computer is starting. The specific key depends on the computer, but it is often the DELETE key or the F2 key.

1Among the sites from which ODIN can obtained are PlanetMirror and The University of Porto.

Created July 19, 2005.
Copyright © 2005 The Linux Information Project. All Rights Reserved.