Reply to post:

It certainly does look vague.

I'm wondering though, is there any really big deal? I'm not entirely sure how one would define where an OS ends and applications start, and whether a lack of development in the OS is a major deal.

The Linux kernel gets updated a lot, and that's pretty cool if you're wanting the latest and greatest kernel features for x64 chips and the eradication of vulnerabilities, etc. However, they're very careful to not break user-land (I can imagine that doing so is good fun - Linus baiting as a recreational activity). But Solaris's kernel, on SPARC, just how much updating is actually required to keep it viable and useful? I can't see Oracle not supporting it on newer SPARC silicon, or failing to fix identified vulnerabilities.

I can see it becoming a problem though if some major user-land package becomes desirable, and the authors of it have gone and made something hideous like systemd a dependency. Solaris doesn't have systemd. Oracle would have to do quite a lot of porting then to accommodate such a package. There's a big trend these days for containers, things like that, but Solaris already does pretty well in that direction, and Sun were amongst the pioneers of quite a lot of that stuff anyway.

But without that kind of issue, most user land stuff should run just fine on Linux or Solaris with no real compilation problems. Solaris can even run Linux binaries without recompilation if required.

Is there perhaps some parallel between Solaris and Windows 7? Windows 7 was, arguably, perfect and pretty much complete, perhaps could have benefited from some under the hood tweaks, etc. Instead MS took it upon themselves to dispose of the entire existing software base (well, demote it to a 2nd class status with a not-shown-by-default desktop) when they did Windows 8. Then 8.1 drew back from that a little bit, 10 more so. The proper, boring, and almost no effort thing for them to have done was simply to tweak 7's innards (for example, 8, 8.1 and 10 have some good improvements to certain aspects of the kernel) but otherwise left well alone.

So perhaps Solaris is in that same place - there's literally not much to be done to keep it rolling along just nicely.