Microsoft's worry over Linux is partly why they're pushing their TCPA legislation. Microsoft doesn't want only to sell the OS on every server in the Internet, they want to write the OS on every server in the Internet. They want every server to support their proprietary, undisclosed protocols.
Note that IBM also supports TCPA initiative.
http://www.ibm.com/news/2001/01/29.phtml(one of the founding members).
IF Apple doesn’t support TCPA and IBM does support TCPA; then this indicates to us that the TCPA system needs both hardware and operating system be aware of TCPA.
This HW and OS chain must be unbroken for the TCPA system to work. In the Apple's scenario; It would be non-TCPA OS (e.g. MacOS X) on top of TCPA hardware (e.g. yet another IBM PPC). This principle can be applied to X86 world.
Thus, Linux will be OK under AMD64 (a.k.a X86-64), and PPC processors.
The real issue here is the “content” i.e. future “content(s)” may not work on non-TCPA eco-systems.
**Content may range from applications, music, movies, pictures, documents and ‘etc’. But any human devised security can be circumvented.
