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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,82095253a0df24a1 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-01-19 00:40:02 PST Path: archiver1.google.com!news2.google.com!news.maxwell.syr.edu!news2.telebyte.nl!newsfeed.stueberl.de!newsr1.ipcore.viaginterkom.de!btnet-peer1!btnet-feed5!btnet!carbon.eu.sun.com!new-usenet.uk.sun.com!not-for-mail From: Ole-Hjalmar Kristensen Newsgroups: comp.lang.ada Subject: Re: "everybody in the control room is using Java" Date: 19 Jan 2004 09:21:11 +0100 Organization: Sun Microsystems Message-ID: References: <1074275354.853176@master.nyc.kbcfp.com> <49cbf610.0401170658.55862afb@posting.google.com> NNTP-Posting-Host: khepri06.norway.sun.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: new-usenet.uk.sun.com 1074500471 4006 129.159.112.195 (19 Jan 2004 08:21:11 GMT) X-Complaints-To: usenet@new-usenet.uk.sun.com NNTP-Posting-Date: 19 Jan 2004 08:21:11 GMT User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/21.2 Xref: archiver1.google.com comp.lang.ada:4545 Date: 2004-01-19T08:21:11+00:00 List-Id: >>>>> "DL" == Dmytry Lavrov writes: DL> "Martin Dowie" wrote in message news:... >> "Hyman Rosen" wrote in message >> news:1074275354.853176@master.nyc.kbcfp.com... >> > >> >> Yeah, not the real thing though!.. >> >> http://www.ghs.com/news/230811j.html DL> http://www.cobalt.com/aboutsun/media/features/mars.html DL> http://www.linuxdevices.com/news/NS3674252711.html DL> Interesting thing, that so called "java technology" ."It's powers the DL> rover from earth" :) DL> Major problem in mars missions is probably programs portability and DL> execution with as much as possible limited access to hardware(no DL> access to things like ports,legs,cameras,trusters,fans,etc) ,like java DL> applets on my PC where i don't want it to have any access to my DL> hardware except framebuffer memory ? DL> Question: DL> I just can't believe _at_all_ that realtime java will _always_ meet DL> deadline,expecially that someone has proved that. DL> Should be assumed that worsest possible GC(garbage collection) DL> operations could happen between deadlines.That's mean,i think,normally DL> load of processor should be not more than several precents,because DL> processor should be fast enough to do GC.If there's JIT like DL> compiler,situation are even worse,it's should be assumed that all DL> commands are interpreted,not compiled! Or someone should do very DL> pricely analysis.... and it's possible that there will be something DL> wrong with it itself,so it's should be checked.... Don't know about the compiler, but real time garbage collection is essentially a solved problem, provided you do not allocate such large objects that the time to move a single object breaks your schedule. Look in the book "Garbage Collection" by Lin and Jones, or do a Google serach for Henry G. Baker (who now is a venture capitalist it seems) to read his papers. DL> Program should use not more than,say, 1/100th of time(assuming that GC DL> lag 100 times more pricely than normal allocation,and that lag could DL> happen constantly ),and run at <1/20 speed(interpretation)....damn DL> inefficient ,because it's better to have slower and more reliable DL> processors than ,hehe,p4 . Is there any tools for SPECIFIC java DL> platform that will calculate maximal execution time _accurately_? It's DL> should be very hard to make that tool that it will not assume GC lags DL> always like i'm doing. DL> Also,there's no doubling for software if there's same runtime in both DL> rovers. -- C++: The power, elegance and simplicity of a hand grenade.