A plurality of local network groups of computers (102) are coupled together by a network (104). Independent processing systems that execute a single operating system are coupled together by a network (220) to form the local network groups. The independent processing systems may have more than one CPU (202). One or more of the independent processing systems may share power, cooling and a housing, thereby forming a common fault processor group (200). An application is written to execute across multiple independent processing systems and common fault processor groups. That is, the application runs in many instances that each run on independent processing systems. The multiple instances of the application provide some measure of high availability by using N+K sparing or the like. The application is for example, call processing or radio control. A processor notification list (304) keeps track of the independent processing systems that cooperatively provide an application. The independent processing systems monitor state information for independent processing systems on its processor notification lists. Also, the independent processing systems exchange messages periodically with independent processing systems on its processor notification list. The failure to receive a message is noted as a failure that requires recovery.Multiple high availability software systems are permitted to coexist under a single operating system by virtue of a new software layer that coordinates initialization and requires registration of all high availability software.