Quote:
that doesn't mean that Linux doesn't change stuff out with little ramification.


Huh? Linux is an operating system kernel. It didn't exist in 1991. By 1992 it was a complete OS. By 1999 many of the major subsystems (network, RAID, various filesystems, etc..) had been replaced with better implementations.

For the past decade (give or take a year), *none* of this has had any significant external regressions. Lots of new stuff, for sure, but the old stuff is still there and still works. I still do my company invoices on a WordPerfect binary from the mid-1990s.

We actually have a very firm rule requiring no userspace impact when kernel internals are rearranged.
Quote:

They might decide to swap out the RAID system tomorrow with a completely new interface

Not true. Sure, "they" might *add* another RAID implementation, but the one that's there now will also have to stay put for a very long time -- we require it.

Okay, so now look beyond the kernel itself to the whole system. Redhat is the longest lived example, and they've tried very hard to remain more-or-less "the same" in clients eyes. Which is why I dislike them, of course: their distro is still living in the late 1990s, while newer ones (like Ubuntu) with no legacy-base have been free to build in mid-2000s code.

Cheers