
Linux only has a small percentage of the computing market, however Microsoft already considers it a major competition as the open source OS steals the hearts of many users. Following the hard numbers though, Microsoft also increases its market share on both server and desktop space with time. The only logical explanation is that Linux steals quite a market share from the traditional UNIX providers (SCO, Sun, SGI, HP, IBM). But only Sun seems to truly be in a real Linux trouble, as it is the one with a resistance to Linux integration to its full product range.
Work in a company with an MS IT shop (I am a research chemist not an IT professional). A year ago I told our CEO as part of my Linux evangelism that you could run Oracle on Linux - He said "I didn't know that". Today our first onsite Oracle deployment is running on RHAS. If our IT people had been allowed to carry on in their MS monoculture way they would have have deployed it on Windows. It wasn't my Linux evangelism that was responsible for the decision it was pressure from both Oracle and our North American IT dept. which is running Oracle on AIX - They told them if you want support you have got to run on some kind of Unix. So for economy they wanted an x86 system, hence Linux.
So in away this decision took away from both MS and proprietary UNIX - Linux being the third option that was chosen.
I like many Linux users have a soft spot for Sun, the first Unix system I ever used was a Sun 3 workstation using SunOS as a grad student. I am also grateful for their contribution to open source: NFS, OpenOffice.org and the Gnome usability work. I wish them the best of luck but they are going to have to work out a consistent Linux strategy to prosper. Their emphasis on network computing gives them more of a chance than most people think.
My feeling that in the server market Linux is taking market share from both MS and proprietary UNIX. It us stopping they entry of MS into current UNIX shops on the back of Intel hardware and also beginnig to to chip away at MS servers in MS shops both at the bottom edge server end and at the mission critical top end (like my company).
If we are to to have real universal computer interoperability their are two alternatives - free open standards were many operating systems can interact (Linux, the BSD's including Darwin, propietary UNIX and even BeOS) or a proprietary OS monoculture where a single monopoly i.e. MS decides on its on secret protocols which they then try to make their own proprietary IP. I know what I prefer
which is why I detest MS not because I think their software sucks but because it has now become a threat.
There is one tue operating system Unix, and Linux is its current manifestation - Amen (just a joke - maybe)