María Ángeles Díaz Fondón

An Object-Oriented Abstract Machine as the Substrate for an Object-Oriented Operating System

Using an object-oriented abstract machine brings a number of benefits for the construction of an object-oriented operating system. In this paper we describe the structure of an abstract machine designed for this task. This machine provides the basic object model and support for the rest of the system. Among other options, we propose a reflective architecture as a collaboration mechanism between the machine and the OS. Finally, we show how using this architecture based on the abstract machine improves and facilitates the construction of operating system features like orthogonal persistence, object distribution, concurrency and capability-based security, giving a flexible integral OO computing environment.

Merging Capabilities with the Object Model of an Object-Oriented Abstract Machine

The evolution towards heterogeneous distributed interoperable objects multiplies the need to have robust fine-grained object protection mechanisms in order to allow only authorized method invocations. Oviedo3 [1] is an example of these kind of Object-Oriented Integral Systems (IOOS) based solely on the OO paradigm. A reflective OO Abstract Machine (OOAM) is coupled with an OO operating system composed of a set of user objects providing OS functionality.

Capability-based protection for integral object-oriented systems

Protection is an essential issue for the heterogeneous distributed interoperable environments, which Java and CORBA are a glimpse of. A uniform protection mechanism such as capabilities integrated with the object model of the system is a good and flexible solution for these environments. Oviedo3 is an example of an integral object oriented system (IOOS) based solely on the OO paradigm, developed over an OO abstract machine (OOAM) and OO operating system (OOOS). When integrated with the object model of the abstract machine, capabilities gain new advantages such as automatic protection. Capabilities also allow more flexible security policies. Existing platforms such as Java, without a uniform protection mechanism, could be made more suitable for these new environments by applying these benefits.