If you look at, say, the Macintosh OS/X system, you're looking at a BSD-Unix-plus-Mach based system that (now) runs on PowerPC or
Intel platforms. (And if you doubt that "real world production work" is done on those machines... just sit down and watch a movie, or listen to a CD, or watch television.)
From a perfectly pragmatic point of view, based on the nearly twenty ...
... years that I have now been in this business myself, the only
constant is change.
(Although it is supremely ironic that the rising-star is an offshoot of an OS that started in the early 70's on a PDP-8!) No matter how long a particular company has been dominant, it just don't mean a thing when something better comes along -- even if it overtakes only some and not all of the dominant player's market segments. You will
encounter Linux, more and more, and you had better make yourself competitive, or at least cognizant, in that new world now
Oddly enough, Linux makes it possible for you to do this "the way we did it," which is to sit down in front of a computer, start reading manuals (man
-pages) that are presented to you in a Courier type-face, and fiddle with it
for a very long time .. solving one problem after another. There is no raised-floor, and the machines are considerably more powerful, but the learning process is the same.
that I am not lapsing into "these kids today..." but, in a very real sense, if all
that you know or have been exposed to is Microsoft Windows, and this only as an application
programmer, then ... well ... you've been coddled.
Microsoft has done its job for you, over the years, much better than you ever knew. And now, it's time you knew.
Linux is, in a certain sense, "computing with the kid-gloves off." It's not hard to learn, really, but it demands that you learn a lot,
and this is precisely what you need