The whole Forbid() Permit() problem only affects old software on the old AmigaOS.
New software written for a new OS, such as a New AROS or new MorphOS can use semaphores to access the various protected OS structures.
So new software on a new OS can make full use of multiple processors.
Someone just has to code up a SMP-friendly new AROS, right?
Then I can start coding up gamez that make use of multiple cores, right?
