RM is an experimental prototype that supports the use of distributed services by personal computers in a LAN. Using a service request model, RM allows any PC on the LAN to offer and use services, which can be user-written or off-the-shelf applications. A user can start several activities that proceed concurrently and that use services offered by different machines. Program interfaces are provided for the development of distributed applications. Remote execution is supported within the service-request framework. The paper considers issues in resource sharing and discusses the choices that were made for RM. It provides an overview of RM concepts, design, and implementation, and reviews experience using the system.

A set of architectural extensions to a machine of the type of IBM System/370 is proposed. The proposal involves hardware/software interaction to constrain the execution-time behavior of application and higher authority programs. The extensions consist of new states of privilege, enforcement of disciplined transition between states, hardware distinction of information types, and a mechanism to control data transfers between main and external storage. Application of the extensions to a shared database system, where users interact through a high-level language, shows that protection of the operating system and the database can be enhanced significantly with respect to errors or deliberate attacks from users

An authorization model is presented, applicable to a shared data base with well defined data structures. Access to this data base is made through a high level language, which is extended to permit data manipulation and to provide data views for different applications. The authorization model includes: 1) the explicit introduction of the concept of application into the definition of user rights; and 2) the use of predicates that can depend on any data in the system to control access at the data field level. Enforcement of authorization is distributed along time (mostly at compile time), and uses the view mechanism to make evident the application program data requests, which are checked by a centralized procedure that consults the access matrix. The system is shown to provide comprehensive authorization, including implementation of levels and compartments, special access restrictions, content-dependent, context-dependent and functional access.

A data structuring scheme for authorization purposes is presented, that: