The DR-DOS/OpenDOS Enhancement Project

(Please note that the links in this document no longer work)

Many PC users in the world use DR-DOS because of its advanced features. In mid 2002, however, the development of DR-DOS seemed to have stopped and the last version had been released more than three years ago. Since there is no other PC operating system that combines so many useful features with full PC compatibility, I decided to write my own set of patches for DR-DOS to fix some bugs and add support for new standards. Since the source code of later versions of DR-DOS was not freely available, I decided to use the source code of DR-DOS 7.01, better known as OpenDOS, as the base for my work. Originally, I had only planned to make minor modifications to DR-DOS 7.01, like adding support for large disks, fix some bugs, etc., but with each successive version, the scope of the project increased, thereby extending the original concept of DOS.

You will find the latest patches at http://www.drdosprojects.de, the project's official web site. Since it has got its own domain, this should not change anymore.

To use the supplied patches, you need the following:

• a copy of the original Caldera OpenDOS 7.01 source code archive (DOSSRC.ZIP)
• a tool capable of unpacking ZIP archives
• a utility to apply the patches to the source
• the development tools MASM 6.0b and Watcom C/C++ 10.0a (other versions may work as well, but this has not been tested)

Note that the source code patches are not cumulative, meaning that you have to apply the earlier patches to the source code as well, with the exception of Work-In-Progress (WIP) and Release Candidate (RC) versions; these refer to the previous main release version.

For those who do not want to compile the source code themselves or lack the necessary development software, there are also pre-compiled binaries available.

OpenDOS had originally been released by Caldera under a commercial license, and it is still bound to this license. If you plan to use OpenDOS for commercial purposes, you need a commercial license for it from either Caldera or the company that now owns DR-DOS/OpenDOS, DeviceLogics (or like they seem to call themselves now, DRDOS, Inc.). The original Caldera license agreement is in the file license.txt, and it also applies for any modified versions that you can download here, as far as they are based on OpenDOS, except that you should not contact their tech support on matters specific to the modified versions. You should read license.txt before you start using any of them.

If you use these patches or the precompiled binary versions on my web site, you do it at your own risk. I am not responsible for any damage that might occur to your hardware or data from using them. Due to the experimental nature of these patches and lack of time on my side, I cannot provide extensive technical support for them. However, if you find a bug that I have not been aware of, or if you want to tell me something that you think I should know, you should post a message in

• the Enhanced DR-DOS forum at http://www.drdosprojects.de/forum/drp_forum/ which I usually check at least once in a few days. This forum is also an excellent place to ask any other DR-DOS related questions or discuss any DR-DOS topics with other members of the DR-DOS community.