The migration pattern at most companies has been from Novell/Unix/VMS to WIndows, and now very solidly back towards Unix. The shift back to Unix happened in the mid-90s and had serious momentum by the very late-90s (maybe 1999-2000 timeframe). Unix, and particularly Linux, is
pervasive in the data centers of the largest corporations these days and is generally trusted on the backend more than Windows by a longshot. As long as Linux continues to deliver the goods value-wise and scalability-wise compared to Windows, they will be virtually impossible for MS to unseat on the backend. Linux has too much mindshare and too few flaws to be seriously vulnerable to being pushed out by MS.
This is largely the fault of Microsoft. If NT 4.0 wasn't such a dog as a server they should have had that market sewn up. As it was, it took them forever to get a decent new server OS version together and Linux was an upstart that just happened to be in the right place at the right time.
Microsoft may have serviceable server product now (though a FreeBSD box will still clean its clock), but everyone has already made a huge investment going back to Unix, and unlike MS, they aren't blowing their current advantage. MS gave Linux a window of opportunity, and now Linux scales better and with higher availability than Windows can in addition to owning a fat chunk of the OS share in data centers. I'm sure Microsoft has been kicking themselves ever since. And of course, IBM has seized this opportunity to hammer MS over some old bad blood, which is no small part of the overall equation that has given us the current market condition. It is a healthy market overall.
The dark horse is MacOS X, which with its FreeBSD pedigree and soon to be available 64-bit IBM core could be a real contender on the server side. It depends on what Apple does with it execution-wise, but they are making all the right noises and the platform components (FreeBSD on 64-bit IBM core) are top-shelf.
You sure? Check the latest:
http://www.esj.com/enterprise/article.asp?EditorialsID=576 Server market contracts; Unix server revenues plunge—again
Not surprisingly, IDC found that Dell Computer Corp. posted the strongest showing during Q1, growing its revenues by 15 percent over its Q1 2002 total.
According to IDC, Microsoft Corp.’s Windows and the open source Linux operating environment were the chief beneficiaries of the sharp uptick in low-end server sales. Sales of Microsoft’s Windows-based server operating system increased by 10 percent in Q1 2003, tallying $3.2 billion. Linux-related revenues exploded by 35 percent, topping off at $583 million.