IBM's Strategic OS

Developing Operating Systems cost money!

OS/400 at its peak had about 5,000 developers working on it in Rochester, Minnesota.  Today there are about 100 left.  There were thousands of developers working on zOS and AIX.  All of these operating system have reached their peak and have maxed out in terms of both new sales and support revenues for IBM. 

On an industry scale Microsoft Windows is the dominate operating system with over 90% of the servers in the world running Windows.  Linux is second followed by all of the UNIX versions then all others including zOS and IBM i bring up the rear.  You cannot find IBM i or zOS in any public studies of OS usage any longer.  Nintendo and Sony rate higher than these OS's.

IBM is focused on LINUX.  Linux is rapidly replacing proprietary Unix operating systems like IBM's own AIX, Sun's Solaris, HP's HP-UX,  AT&T's BCD Unix, etc.  Linux is free, it is open source, and it runs on every single platform that IBM builds.  Application programs are totally portable, unlike Unix.

IBM xSeries (their Intel servers which also support Windows), Power Servers (which also supports AIX and IBM i), and the zSeries (which also supports zOS) all support Linux. 

IBM can make more money providing services and support for Linux than maintaining the expense of developing operating systems.  IBM will focus on virtualization technologies that allow them to maximize the utilization of a single machine and sell enormous SAN's (Storage Area Networks) with Terabytes of data storage spread across multiple locations. 

Note that IBM's WebSphere brand is also going by the wayside.  It is also being displaced by open source software.

IBM has found that providing services for existing open source software is much more profitable than developing and competing with open source.