A brief and incomplete recent history of DR-DOS:
Novell bought DR-DOS from Digital Research a few years back. They enhanced it with multi-tasking and multi-threading, included the GEM desktop GUI, added better memory mangement (try 600+KB with all drivers and network software loaded), and bundled in the Personal NetWare product to give it peer-to-peer networking abilities.
They were unable to market it successfully, because of Microsoft's (since outlawed) practice of requiring computer makers to pay MS a license fee for MS-DOS for every machine sold, whether it had MS-DOS on it or some other operating system.
This inability to market Novell DOS also killed their project with Apple whereby they were going to produce a 32-bit version of DR-DOS with the Apple GUI interface that was able to run Windows applications.
Novell has since sold the DOS product to a company called Caldera (www.caldera.com or www.caldera.co.uk), which is further enhancing the product and marketing it as OpenDOS, an OS for embedded controllers, thin Internet clients (they've also developed a browser that run on OpenDOS), and similar uses.
Caldera is also suing Microsoft for antitrust, unfair practices, and monopolizing.
Caldera has promised to make the source code for OpenDOS available to anyone, and OpenDOS may be used (modified or otherwise) without a license for any non-commercial use (i.e. your home computer). It is NOT freeware, public domain, shareware, or GPL. It is copyrighted by Caldera.
You can download OpenDOS from the Caldera web site.
Jerry |