IIRC Xbox had been criticized for quite a while at that point for having very few exclusive/first-party games worth buying an Xbox for. I always assumed this move was to try and fix that problem.
I think NLMs are effectively kernel modules. No memory protection, and only cooperative multitasking. So I doubt there were much in the way of limits on what an NLM could do.
I think they were usually developed in C. Metrowerks had a compiler that could build them, and Open Watcom can still do so as well.
Thats the DR-DOS/OpenDOS Enhancement Project. Its a set of patches for the Caldera OpenDOS 7.01 kernel.
The license file inside the original Caldera OpenDOS 7.01 source archive says:
"Caldera grants you a non-exclusive license to use the Software in
source or binary form free of charge if (a) you are a student,
faculty member or staff member of an educational institution
(K-12, junior college, college or library), a staff member of
a religious organization, or an employee of an organization which
meets Caldera's criteria for a charitable non-profit organization;
or (b) your use of the Software is for the purpose of evaluating
whether to purchase an ongoing license to the Software. The evaluation
period for use by or on behalf of a commercial entity is limited
to 90 days; evaluation use by others is not subject to this 90 day
limit but is still limited to a reasonable period."
So that website is incorrect when it says OpenDOS was released under an open-source license. Not surprising though - most websites discussing OpenDOS make this error. Possibly because at the time I believe Caldera did actually talk about open-sourcing DR-DOS, they just failed to to actually follow through.
If he still has the source code, whats needed is for Bryan Sparks to release it under some regular open-source license like Microsoft have done here.
DR-DOS hasn't been open sourced. Caldera did release the source for the kernel and a few other bits, but the license only allowed free use for evaluation purposes. After 90 days (for a company) or "a reasonable period" for non-commercial entities you were required to buy a license.
Bryan Sparks did open-source CP/M a little while back, but AFAIK he hasn't said anything about DR-DOS so far.
OpenDOS isn't open-source, its source-available. The license reads more like trial software:
"Caldera grants you a non-exclusive license to use the Software in source or binary form free of charge if your use of the Software is for the purpose of evaluating whether to purchase an ongoing license to the Software. The evaluation period for use by or on behalf of a commercial entity is limited to 90 days; evaluation use by others is not subject to this 90 day limit but is still limited to a reasonable period"
The Multia used the cut-down LCA4 or LCA45 (Low Cost Alpha) CPU, the 21066 or 21066A. These apparently performed worse than the more expensive EV4 or EV45 parts.
Also, the compilers on Windows NT were from DEC, at least to some extent. In the NT 3.50 SDK there is a manual from DEC explaining what the compiler was - a customised Microsoft C/C++ frontend combined with a port of the GEM backend from Unix or VMS.
IIRC Xbox had been criticized for quite a while at that point for having very few exclusive/first-party games worth buying an Xbox for. I always assumed this move was to try and fix that problem.