[davidgnz]

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.

[snvzz]

There was an actual open source version, which was retracted[0].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

[davidgnz]

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.