computer security

a) The Operating system is crucial for getting some level of security in a computer system. One basic technique used to get it is by separation. The most common form of separation used is logical separation. Describe how that type of separation works. b) Memory protection is one of the methods applied in operating systems. Shortly describe a few methods used to implement memory protection. c) One of the tasks for the operating system is authentication. Name four different ways to authenticate a person in an operating system. (4+4+4 p)