Twelve years after Microsoft announced it would stop development of DOS, an open source replacement - FreeDOS - has hit its 1.0 release.

The FreeDOS project was launched in a 1994 manifesto by free software developer Jim Hall, following Microsoft's announcement that it would stop developing DOS with the launch of Windows 95.

The resulting operating system is fully open source, with most components covered by the GNU General Public License, and provides MS-DOS compatibility to the extent of being able to run some versions of Windows.

The project was planned to hit 1.0, the mark of maturity in the open source world, at the end of July. Developers said the operating system supports several features that never made it into the officially supported Microsoft versions, such as internationalisation, power management and ASPI.

Other features in the 1.0 version include long filename support in some applications, the FAT32 file system, HIMEM, EMM386 and CD-ROM. USB isn't directly supported.

Add-on applications include an audio player, a window editor, an HTML viewer and an archive program. FreeDOS can be used to run most DOS programs, including games and older business software, can support embedded DOS systems such as cash registers, the project said.

"FreeDOS 1.0 is a major milestone that has finally been released. By now, we have a stable and viable MS-DOS replacement," wrote developer Blair Campbell on the project's website.

The operating system supports hardware from the 1981 IBM PC through to current Intel-compatible processors and embedded chips. It can be run on dedicated hardware or in an emulator on top of most other operating systems, developers said.

The project has released a CD-ROM image for FreeDOS here, and is planning a more extensive CD-ROM release and a full set of floppy disk-based images.

Programmers may have been able to recreate MS-DOS from scratch, but it would be a more difficult proposition to take the same approach with an open source Windows. More recent versions of Windows, such as NT, Windows 2000 and Windows XP no longer use DOS as a core component and are byzantine in their complexity.

However, the WINE project, and offshoots such as CodeWeavers' CrossOver products, have achieved significant success in running Windows applications directly on other operating systems, such as Linux, without the need for full Windows emulation.