One of the problems confronting corporations, research laboratories, and universities is that of providing and allocating effective computer services. The problem of allocating the resources is complicated by the variety of alternate sources available to serve the multiplicity of user needs and by the variety of methods of charging the users for the service (35:541). Many organizations treat computer resources as a utility, and the user is charged for usage of the facilities. The task of charging the user for his "fair" share for usage of the computer facilities has been complicated since the advent of sophisticated operating systems or executives which may allow for concurrent use of the CPU by several users (1:13).
