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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,894846be18e92713 X-Google-Attributes: gid103376,public From: "Marin David Condic, 407.796.8997, M/S 731-93" Subject: Re: GNAT R/T Annex and Win95 Date: 1996/04/19 Message-ID: <96041916380674@psavax.pwfl.com>#1/1 X-Deja-AN: 150416899 sender: Ada programming language comments: Gated by NETNEWS@AUVM.AMERICAN.EDU x-vms-to: SMTP%"INFO-ADA@VM1.NODAK.EDU" newsgroups: comp.lang.ada x-vms-cc: CONDIC Date: 1996-04-19T00:00:00+00:00 List-Id: Robert Dewar writes: > >Ada 95 does not require run-till-blocked semantics unless the RT annex >is supported fully. Not all OS's can support the real time annex, and >clearly GNAT on such a system does not support the annex (this is >assuming tasks are mapped to threads). On NT, you can map to the >real time threads, and all is well, but I don't know if this applies >to Win95. Anyway, Greg, you are making undocumented assjmptions here! > Here's an interesting question which we've been thinking about around here a lot: Do you consider Windows NT capable of being a "realtime" operating system? (It doesn't seem to be advertised as such.... yet.) We'd like to build some of our data systems and ground support systems around Ada and NT, but we're not sure we can get the needed behavior out of it for a realtime system. (GNAT might even be usable here since most of this is "in house" development and not a contract deliverable. More leeway with what you do in this case.) We need to know things like "If I execute a delay statement, will I wake up and have a deterministic span of time between the clock going off and my code resuming?" Similar questions for interrupt processing and such. Or "will the OS dynamically rescale my task priorities and screw everything up?" Or priority inversions that can occur if a low priority thread uses an uninterruptable OS routine. Lots of things are uncertain about NT WRT its use as a realtime OS. (Of course, you can always buy a processor that executes a quintillion instructions per second and hope the latencies never get big enough to matter! ;-) Opinions? I'd really like to have some best guesses to pass on to the folks here who do these sort of systems. Pax, Marin Marin David Condic, Senior Computer Engineer ATT: 407.796.8997 M/S 731-93 Technet: 796.8997 Pratt & Whitney, GESP Fax: 407.796.4669 P.O. Box 109600 Internet: CONDICMA@PWFL.COM West Palm Beach, FL 33410-9600 Internet: MDCONDIC@AOL.COM =============================================================================== "You spend a billion here and a billion there. Sooner or later it adds up to real money." -- Everett Dirksen ===============================================================================