Fig. 6. A simple capability system. Program A is in control of the processor. Note that there is no way for the processor to address Smith's catalog or data base Y. On the other hand, data base X could be accessed by loading capabUity C~ into a protection descriptor register. CapabUity C' is loadable because it is stored in a segment that can be reached from a capabUity already loaded in protection descriptor register 2. Note also that the former function of the privUeged state bit has been accomplished by protecting the capabilities. The privileged state bit also has other uses and wUI be reintroduced later.