Data processing system using incompatible central processing unit/operating system combinations

A data processing system is disclosed in which the central processing units incorporated therein operate under control of a plurality of (generally incompatible) operating systems. The central processing units have a peer relationship in which each central processing unit has access to all of the system resources, such as main memory locations and input/output channels. Files of currently allocated resources are maintained by each central processing unit. The currently allocated resources can be altered as the requirements of the central processing units change. Apparatus and method are disclosed wherein, once a peer processing relationship is established among the central processing unit/operating system combinations, a user can execute software programs operating under any of the data processing system central processing unit/operating system combinations thereby taking advantage special execution capabilities of selected central processing unit/operating system combinations.