DR-DOS - - Growing article, with links to many related topics. Wikipedia.
DRDOS, Inc. - - Makes: DR-DOS, compact, Y2K safe, good for embedded or thin-client systems, source code available, development kits, older and localized versions; and DRLX embedded Linux, load and run Linux programs from DR-DOS.
DR-DOS Wiki - - Information of many types on DR-DOS, Enhanced DR-DOS, OpenDOS, NovellDOS.
The DR-DOS/OpenDOS Enhancement Project - - Goal: continue development, enhance abilities of, add support for new standards to, extend life of this DOS under open source license. Descriptions, downloads of latest versions: source code, binaries, patches.
OpenDOS - - Growing article, with links to many related topics. Wikipedia.
OpenDOS Unofficial Page - - Descriptions, questions and answers, downloads, mail lists, programming information. Not up-to-date, but has useful information, some of historical interest.
Unofficial DR-DOS Resources - - Links, install and use tips, FAQ; mail lists, newsgroups, fora; downloads: images, source code; tools.