DR-DOS

This operating system has quite a history now. It was developed by Digital Research (hence the name), the makers of CP/M. Later it was acquired by Novell, who bundled it with Personal Netware. Then, under Caldera's ownership, it became OpenDOS and was free for personal use. This still applies to 7.01 and 7.02.

7.03, released 1998, was commercial again. A new owner, DeviceLogic, developed a FAT-32 enabled version 8.0, released March 2004. DRDOS became the property of yet another company, simply named DRDOS, who released 8.1 in October 2005. Both 8.0 and 8.1 had to be pulled because they incorporated FreeDOS code while being closed-source, thus violating the GPL. 7.03 is still sold as of 2011.

You can also buy the whole troublesome project for $25,000.

Advantages

• No minimum system requirements.
• Comfortable command line, you can browse through your previous commands and edit them.
• Extensive hypertext online documentation.
• Built-in networking, a lite version of Novell Netware, unfortunately not compatible with the real thing.
• Built-in multitasking, either in the form of simple task switching (useful if you want to switch between an editor and help, or between a game and its manual), or true multitasking on a 386 or above.
• Compatible with nearly every DOS program. The only thing that won't run on it is ScreenThief.

Disadvantages

• Takes up 5 MB of disk space, 10 MB with networking. This is quite a chunk on a really old computer.
• Limited wildcard support. MS-DOS (at least 7) will understand something like *string*.*. DR-DOS will interpret this as *.*.
• The bundled mouse driver is rather limited. It won't work correctly with 80×43 text mode (you can't move the cursor below line 25), and it doesn't seem to work with high-resolution EGA graphics.

Windows 3.1

You can install Windows 3.1 on top of DR-DOS, but it will replace the DOS memory manager with its own. Windows' memory manager is command line compatible with its MS-DOS counterpart, but not with the one used by DR-DOS. You will thus get an error at startup.

This is, however, easily fixed, just go back to using DR-DOS' manager. The Windows installation routine will just comment the line out, not delete it.

Links

• Official DR-DOS Homepage
• Some historical information
• Club Dr-DOS - Unofficial Dr-DOS page
• Unofficial DR-DOS Information Website
• The DR-DOS/OpenDOS Enhancement Project
• OpenDOS Unofficial Homepage from 1997
• FTP Uni Bayreuth (download 7.01 and 7.02 here)