From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: * X-Spam-Status: No, score=1.1 required=5.0 tests=BAYES_20,INVALID_DATE, MSGID_SHORT autolearn=no autolearn_force=no version=3.4.4 Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!decwrl!decvax!mcnc!gatech!hao!husc6!bbn!uwmcsd1!tut.cis.ohio-state.edu!ut-sally!utah-cs!utah-gr!uplherc!sp7040!obie!wsccs!wes From: wes@wsccs.UUCP (Barnacle Wes) Newsgroups: comp.lang.ada Subject: Re: Tasking and delays, again Message-ID: <204@wsccs.UUCP> Date: 26 Feb 88 21:40:48 GMT References: <8802160441.AA16876@ajpo.sei.cmu.edu> Summary: Tasking questions (no answers here!) List-Id: In article <8802160441.AA16876@ajpo.sei.cmu.edu>, MFELDMAN@GWUVM.BITNET (Mike Feldman) writes: > 1. A and B have the same priority > > 2. A has higher priority than B > > 3. B has higher priority than A > > If I read the recent discussion of AI-something correctly, a legal > system in which 2 or 3 is even possible must, somehow, interrupt. Am > I correct in this reading? Does it make any difference if case 1 > obtains? > I can't answer your questions, unfortunately, but I do know of some code for an Air Force command and control system that would break (horribly) if the Ada compiler did not support pre-emption. By pre-emption I mean: process A has a higher priority than process B process B is currently running process A becomes ready to run due to some event most of the executives I have worked on in command and control systems need to be guaranteed that A will run within a specified amount of time, or they would not work at all. C2 messages would be scrambled or lost. Does the Ada language allow tasking systems that do not support time-slicing of some sort on single-processor systems? -- /\ - " Against Stupidity, - {backbones}! /\/\ . /\ - The Gods Themselves - utah-cs!utah-gr! / \/ \/\/ \ - Contend in Vain." - uplherc!sp7040! / U i n T e c h \ - Schiller - obie!wes