I think there's also a general suspicion that Sun could have just chosen the GPL if they cared about compatibility. Although, for various reasons, it's probably at least somewhat more complicated than that because of patent protection, etc.
> I think there's also a general suspicion that Sun could have just chosen the GPL if they cared about compatibility.
There were 'technical' reasons why they did go not with GPL, and specifically GPLv2 (GPLv3 was not out yet). IIRC, they did consider waiting for GPLv3, but it was unknown when it would be out, and one thing they desired was a patent grant, which v2 does not have.
Another condition was that they wanted a file-based copyright rather than a work-based copyright (i.e., applies to any individual files of ZFS as opposed to "ZFS" in aggregate).
I had forgotten about some of the reasons they specifically wanted file-based copyright. Sun were clients at the time and I spoke fairly frequently with the open source folks there. But I didn't remember all the details and was certainly not privy to all the internal discussions.
"Sun could have just chosen the GPL if they cared about compatibility."
That's a very loaded statement. I've seen it said quite a lot over the years. But, have you thought about its implications?
The implicit assumption here is the primacy of the GPL over all other open source licences. Why should other companies and organisations treat it as "more special" than any other free/open source licence when it comes down to interoperability?
When it comes down to compatibility, the GPL is one of the last licences you should choose. Because by its very nature it is deliberately and intentionally incompatible with everything other than the most permissive licences. The problem with "viral" licences like the GPL is that "there can only be one" because they are mutually incompatible by nature. Why should the MPL/Apache/CDDL licences make special exemptions to lessen their requirements so that they can be GPL-compatible?
I should have written compatibility with the GPL (or really the Linux kernel which was what was most relevant from the perspective of Solaris). And, of course, Sun could have chosen a fully permissive license but AFAIK nothing like that was seriously considered.
Nit: Apache 2.0 is compatible with GPLv3 (but not v2).
I think there's also a general suspicion that Sun could have just chosen the GPL if they cared about compatibility. Although, for various reasons, it's probably at least somewhat more complicated than that because of patent protection, etc.