Do the fish really need remote control? A proposal for self-active objects in Oberon

Abstract

Based on the language Oberon we propose a unified framework for concurrent, object-oriented programming. Inspired by simulation, the idea is to regard objects as processes in contrast with the more common approach treating processes as objects. More concretely, our framework extends the original Oberon language by four new concepts: (a) Object-centered access protection, (b) object-local activity control, (c) system-guarded assertions and (d) preemptive priority scheduling. (a) and (b) are expressed syntactically by upgraded record types, (c) by a passivation/activation mechanism and (d) by a priority option. None of the conventional facilities like semaphores, locks, critical regions, signals, channels, rendez-vous, forks etc. are primitive constructs in our framework. Currently, an implementation of a compiler, a corresponding runtime kernel and a non-blocking local server exists for native Intel architectures.

A messaging architecture for distributed objects in Oberon

“…While the original Oberon system was specifically designed for single-workstation operation, future system revisions may include some proposals of section 2.3 in order to provide improved built-in support for distributed objects. In this respect, the proposed Active Objects [6] (Oberon language extension) seem a highly interesting concept as they provide amongst others preemptive priority scheduling (addressing our most important issue) and object-local activity control (eliminating the need for coroutines or a workaround).…”

A high-performance operating system for structured concurrent programs

“…Concurrency. Modern and advanced programming languages [3,12,10,7,17,11,6] usually offer concurrency as a primary programming concept, which is directly associated with objects or components. Instead of primarily programming with procedures, such languages Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page.…”

Structuring a Compiler with Active Objects

“…This section recapitulates the Active Oberon language [7], an extension of the Oberon language [16,18]; it is a homogeneous integrated concurrent programming language that embeds concurrency support in Oberon, by making just minimal additions to the language and creating a unified framework for concurrent, object-oriented programming. This is done by introducing concurrent activities, protected access and guarded assertions in the language.…”