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=-0.4 required=5.0 tests=AC_FROM_MANY_DOTS,BAYES_00 autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,5bcf30769d6d9599 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-08-28 07:08:45 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!newsfeeds.belnet.be!news.belnet.be!psinet-eu-nl!psiuk-p4!uknet!psiuk-n!news.pace.co.uk!nh.pace.co.uk!not-for-mail From: "Marin David Condic" Newsgroups: comp.lang.ada Subject: Re: ADA os talk Date: Tue, 28 Aug 2001 09:48:41 -0400 Organization: Posted on a server owned by Pace Micro Technology plc Message-ID: <9mg7fr$rm1$1@nh.pace.co.uk> References: <9mdmck$rs1$1@nh.pace.co.uk> <9me6q4$aai1@news.cis.okstate.edu> NNTP-Posting-Host: dhcp-200-133.miami.pace.co.uk X-Trace: nh.pace.co.uk 999006523 28353 136.170.200.133 (28 Aug 2001 13:48:43 GMT) X-Complaints-To: newsmaster@news.cam.pace.co.uk NNTP-Posting-Date: 28 Aug 2001 13:48:43 GMT X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Xref: archiver1.google.com comp.lang.ada:12515 Date: 2001-08-28T13:48:43+00:00 List-Id: We used VMS on engine test stands to collect & process temperature/pressure sensor data in real time. I wasn't in on developing the software, but the requirements were that you could detect the interrupt and have a predictable latency to when you got to the ISR, even if other apps were running. (You had to record the data points at even time intervals - as you say, not necessarily "fast" but predictable.) We were able to run GUI apps at the same time an engine test was going on - albeit with the probability that mouse/window response was going to degrade, but it didn't stop the realtime app from getting serviced when it needed to. IIRC, VMS itself didn't guarantee realtime behavior, but if you took some smart guys and let them study it long enough, they could figure out how to get VMS to do what you wanted it to do. We accomplished the same sort of thing with MS-DOS because basically, you could get your real time app to move MS-DOS aside and just take over. What would be nice is to have a workstation OS that didn't require you to become an expert or circumvent the OS to do realtime - just declare a process to be "realtime" and know that it can get certain services with certain predictable latencies and be sure that it has priority over anything else. (Dangerous, but necessary for realtime programming.) MDC -- Marin David Condic Senior Software Engineer Pace Micro Technology Americas www.pacemicro.com Enabling the digital revolution e-Mail: marin.condic@pacemicro.com Web: http://www.mcondic.com/ "Larry Kilgallen" wrote in message news:MIj1nYP7aabe@eisner.encompasserve.org... > > I would say VMS is a good example, if you agree that: > > Just because there are a lot of applications that are > missing from the GUI interface, that does not mean > there is a technical (as distinguished from marketing) > limit preventing their presence. > > You cannot really get the GUI performance you have come > to expect while realtime processes are running. > > You do have to set process priorities appropriately, and of > course the definiton of realtime is that events are handled > within some predictable timeframe. Certainly someone can > define their timeframe requirements tighter than VMS can > handle, but they could also define those requirements > tighter than can be handled by the hardware -- any hardware.