Transfer Semantics in an Operating System Consultant: The Formalization of Actions Involving Object Transfer

Abstract

It is a characteristic of computer operating systems that they contain actions or commands which transfer objects such as files and directories from one state to another. In formalizing the domain of operating systems we should build representations of actions which circumscribe the transfer of objects in the system. Transfer Semantics is a knowledge scheme that embodies such representations. Knowledge structures called object frames are used to represent numerous objects. Action frames describe the effects of actions in terms of preconditions, postconditions, actions and actors. Preconditions denote possible or preferred sets of objects that an action will affect. Postconditions relate the state of object sets after an action has occurred . Actions include the particular actions that cause transfer. An actor is the person (or user) who performs some action. The power of Transfer Semantics lies in the inference rules that manipulate action frames. It is applied to the UNIX* and TOPS-20* operating systems in a program called OS Consultant. OS Consultant will be used by new users to learn operating system concepts.