Good thing they still offer a $10 product then - the Raspberry Pi Zero.

and the RP2040! There is not much to differentiate it with ESP32 at the moment, but it's their first shot at a microcontroller.

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.

There was an actual open source version, which was retracted[0].

Fortunately for the commons, what's done is done.

0. https://archiveos.org/drdos/

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.

I heard there was some resolution re: copyright mess in the last few years, but I currently cannot find anything about it.

To the point I might have dreamed it. Odd.

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.

the 21066 chips were cache and memory bandwidth starved compared to normal EV4 setup, and IIRC many didn't have the larger cache option. Reports seem to indicate that 233MHz models effectively were about Pentium 100MHz speed in integer ops.

I don't know how many EV4 systems shipped with 64bit system bus, but by 1994 AlphaStation 255 models shipped with 128bit system bus and 1MByte L2 cache, and they weren't particularly high end (I found one that was used by Best Buy to run VHS rental shop...)