Operating systems should be immutable. No amount of installed programs or add-ons should change any of the operating system files. The only exception of course is when the operating system updates itself.

A quick look in my Vista install C:\Windows, I see files that don’t belong: KHALMNPR.Exe (Logitech), War3Unin.* (Warcraft 3 Uninstaller). Why does Windows let (or require) third-party programs add files to the Windows directory? It gets even worst in System32.

Linux is far better in this regard, but it is still possible to replace say ls with another version. I know you’ll need root access, and it is unlikely for this to occur, but I believe it should not be allowed.

The current state of affairs is to allow for customization, configuration, and extension. But these should not modify the operating system, it should be well defined on how to interact with the operating system.

Security and reliability require sacrifices. This proposed immutable system would reduce flexibility, but it would make things simpler and better defined.