With software, the idea is to create some sort of code that is jammed into Linux and whose sole purpose is to let some proprietary code run under Linux without actually "touching" Linux in any way that would subject the proprietary code to the GPL. This would include mechanisms that alter the internals of Linux without having to publish the code and changes as open-source or allow them to be used by others, as is required by the GPL.

Everyone in the business has been trying to cheat the Linux GPL for years, and this shim idea seems to have the earmarks of something that might work. Microsoft knows this, Oracle knows this, everyone knows this.

With a shim, Microsoft could possibly do the following: Take a Linux distro, say SUSE; then create a shim that talks to the SUSE kernel. Publish the source code of the shim and what it does. Then take a proprietary Microsoft optimizer that lets various apps run on Linux perfectly with modifications to the Linux core—but that actually runs on the shim, not Linux. The modifications to Linux would be done by the shim at the behest of the Microsoft apps in such a way that the mechanism would not have to be revealed as open-source. I know it sounds a little complicated to create middleware for the sole purpose of code-scrambling on the fly. But suffice it to say that the plan is something like what I've described.