From: firstname.lastname@example.org (David B Stewart) Subject: Re: Object-Oriented Systems and Realtime Organization: The Robotics Institute, Carnegie Mellon University Date: Mon, 11 Oct 1993 16:51:19 GMT
In article <1993Oct11.email@example.com>, Chris Zimmermann <firstname.lastname@example.org> wrote: >Hi community: > >What is the state of the art concerning real time in >object-oriented systems (if any)? By this, I mean the >marriage of more or less traditional real time systems >(including systems concerned with "soft" real time aspects >like multimedia) with the OO paradigm. >[...]
We've done significant work in that area. Check out the following tech report:
D. B. Stewart, R. A. Volpe, and P. K. Khosla, "Design of Dynamically Reconfigurable Real-Time Software using Port-Based Objects," Carnegie Mellon University Tech Report #CMU-RI-TR-93-11, July 1993.
Abstract: The current development of applications for sensor-based robotic and automation (R&A) systems is typically a `one-of-a-kind' process, where most software is developed from scratch, even though much of the code is similar to code written for other applications. The cost of these systems can be drastically reduced and the capability of these systems improved by providing a suitable software framework for all R&A sys tems. We describe a novel software framework, based on the notion of dynamically reconfigurable software for sensor-based control systems. Tools to support the implementation of this framework have been built into the Chimera 3.0 Real-Time Operating System. The framework provides for the systematic development and predictable execution of flexible R&A applications while maintaining the ability to reuse code from previous applications. It combines object-oriented design of software with port-automaton design of digital control systems. A control module is an instance of a class of port-based objects. A task set is formed by integrating objects from a module library to form a specific configuration. An implementation using global state variables for the automatic integration of port-based objects is presented. A control subsystem is a collection of jobs which are executed one at a time, and can be programmed by a user. Multiple control subsystems can execute in parallel, and operate either independently or cooperatively. One of the fundamental concepts of reconfigurable software design is that modules are developed independent of the target hardware. Our framework defines classes of reconfigurable device driver objects for proving hardware independence to I/O devices, sensors, actuators, and special purpose processors. Hardware independent real-time communication mechanisms for inter-subsystem communication are also described. Along with providing a foundation for design of dynamically reconfigurable real-time software, we are also developing many modules for the control module, device driver, and subroutine libraries. As the libraries continue to grow, they will form the basis of code that can eventually be used by future R&A applications. There will no longer be a need for developing software from scratch for new applications, since many required modules will already be available in one of the libraries.
This report is available via anonymous FTP as follows:
% ftp IUS4.IUS.CS.CMU.EDU (22.214.171.124) Name: anonymous Password: yourname@yourmachine ftp> binary ftp> cd /usr/chimera/public ftp> get CMU_RI_TR_93_11.ps.Z ftp> quit % uncompress CMU_RI_TR_93_11.ps.Z % lpr CMU_RI_TR_93_11.ps (must be a postscript printer)
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