Free DOS-compatible Operating Systems
MS-DOS, PC-DOS, DR-DOS Clones and Equivalents
Free DOS-compatible Operating Systems (MSDOS/PCDOS Clones)
In its heyday, MS-DOS, PC-DOS and its commercial clones, DR-DOS, was used on a large number of computers, with innumerable pieces of software developed for it. While it is now a dim memory today, it can still be used for a number of purposes including its use as an embedded system (for example, inside cash registers), to run old programs and games, or to study its code. It is also useful for those who have lived through that era and want to run it for nostalgic reasons.
The DOS-compatible operating systems listed on this page usually provide a bootable media which you can use to boot and install the DOS variant. Some of them come with a full complement of tools and utilities, perhaps even more than those supplied with the commercial MSDOS of old.
Free DOS-compatible Operating Systems (MS-DOS/PC-DOS Clones)
- MSDOS 1.1 and 2.0
The source code for the old Microsoft DOS version 1.1 and 2.0 is available for non-commercial research, experimentation and educational purposes. In general though, unless you are really using it for those purposes, the software is probably too old to be useful on a modern computer, assuming it can even work on current processors, chipsets, buses and interfaces. You'll probably need an emulator to have a hope of getting it to run.
FreeDOS is the well-known DOS compatible OS that is released under an open source licence. The operating system allows you to run old programs, be it games, business applications or other DOS software, under an environment that emulated the old Microsoft DOS system. It comes with a whole plethora of utilities, including clones of those you can find distributed with MS-DOS and PC-DOS, even things like a replacement for the HIMEM.SYS, EMM386.SYS (memory managers to provide access to memory above the old 640 KB barrier) and MSCDEX.EXE (driver for allowing DOS access to CDROM drives), a mouse driver, etc. However, it goes beyond simply being a DOS clone - it has long filename support in the command.com replacement as well as other tools, FAT32 support, modern archivers like 7zip, zip, unzip, etc. This is a very popular substitute for the old MSDOS among people who still have need for it. It can also be used in embedded systems.
- FreeDOS-32 (FD32)
FreeDOS-32 is a 32-bit reimplementation of MS-DOS that runs in 32-bit protected mode. It is intended to run protected mode DOS programs and has its own 32-bit device drivers. There is also some support for Windows console programs. Unfortunately, development for this operating system appears to have halted, even before it has reached release status. That is, although you can download the system, it is still not in a state that can be used in a production environment (or any environment, for that matter).
- IBM PC-DOS 2000 (Chinese Version)
The Chinese version of IBM PC-DOS 2000 is available free from IBM's FTP site. Unlike some of the other free DOS clones listed on this page, PC-DOS 2000 is fairly out-of-date with no updates since the date it was released. Update: It looks like the software is no longer available (or at least I couldn't access it the last time I tried to check). For the record, it used to be found at
- DR-DOS / OpenDOS Enhancement Project
This site provides source code and precompiled binaries (executables) of the original OpenDOS / DR-DOS 7.01, a commercial clone of MS-DOS that was fairly popular in its day before it was released for free at the end of the DOS-era. There are also newer versions that include updates and enhancements to the original code. These enhanced versions add things like support for long file name (LFN), the newer FAT filesystems, and so on. Update: It looks like the site is no longer available. For the record, it used to be found at
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