Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!apple!snorkelwacker!bloom-beacon!eru!hagbard!sunic!mcsun!tuvie!vmars!alex From: alex@vmars.tuwien.ac.at (Alexander Vrchoticky) Newsgroups: comp.realtime Subject: Re: Software primitives for real-time programming languages Message-ID: <1890@tuvie> Date: 27 Sep 90 10:50:34 GMT References: <12682@cs.utexas.edu> <1844@tuvie> <224@srchtec.UUCP>, Sender: news@tuvie Lines: 34 David.Maynard@CS.CMU.EDU writes: >Alpha is an operating system (and the center of an ongoing research and >development effort) that addresses many of these issues. Alpha is >designed to support distributed real-time systems that may have a >variety of stringent timeliness requirements. The application designer >specifies these time constraints to the operating system using >"time-value functions." Time-value functions express the value of >completing an activity as a function of time. (Hard deadlines are >described as a simple special case where the time-value function is a >step-function.) As part of our research, we have developed (and >continue to develop) a class of resource management algorithms that >utilize time-value functions in the decision making process. This is a great idea for requirements description. But how are the requirements then transformed into a working system? Basically you have a set of time-value functions. I assume that the execution of the system should maximize the `overall value', however it may be defined. What is the next step in the design process? Are the value functions used for run-time scheduling? How do the scheduling algorithms work? >I welcome a discussion of real-time specification methods (such as >time-value functions) that allow you to express the real timeliness >requirements of applications. There is definitely a need for more work >in this area. However, I'm not interested in a discussion that assumes >everything is a nail and tries to decide how long the nail is. Not everything is a nail. Some things are. Those things are called `nails'. -- Alexander Vrchoticky Technical University Vienna, Dept. for Real-Time Systems Voice: +43/222/58801-8168 Fax: +43/222/569149 e-mail: alex@vmars.tuwien.ac.at or vmars!alex@relay.eu.net (Don't use 'r'!)