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: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: 1014db,3d3f20d31be1c33a X-Google-Attributes: gid1014db,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 109fba,2c6139ce13be9980 X-Google-Attributes: gid109fba,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public From: Joachim Durchholz Subject: Re: Safety-critical development in Ada and Eiffel Date: 1997/07/16 Message-ID: <33CBF5DE.D5FB1B6C@munich.netsurf.de>#1/1 X-Deja-AN: 257448418 References: <33C56F97.1223@gsfc.nasa.gov> <5qc53v$kb6@alumni.rpi.edu> X-Priority: 3 (Normal) Organization: ccn - computer consultant network GmbH Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel,comp.lang.c,comp.lang.c++ Date: 1997-07-16T00:00:00+00:00 List-Id: Steve Furlong wrote: > get or free memory. If your process _must_ check ports every 10 ms, > you can't be waiting half a second for memory compaction. Arrgh! Will that idea nevere go away!! The best available GC algorithms don't go away for compacting; they run in parallel with the normal program (as a coroutine if you don't want a preemptive scheduler). > Modern GC presumably can get around that problem, That reads "definitely", not "presumably". The algorithms are there. Besides, hand-crafted GC may look nice on paper, but it's usually less efficient than automatec GC. Manual deallocation means programmers will pass around more copies of objects, defeating the very reason why automated GC isn't used. (The reason is that, if the programmer would just pass the reference, the owner of the object has to worry wether that reference he gave aways is still in use somewhere. If the object is copied, the owner can deallocate the original and doesn't have to worry about the copy - but the copying process itself may be more machine cycles than what would have been necessary to reclaim the single object with automated GC.) > but the purveyors > presumably can't prove its efficacy and response time to the > satisfaction of the FAA and other safety hard-noses. Well, I'm feeling cynical today, so I'd say that the safety gurus just don't know or care about the algorithms, because it's something new and they'd have to *think*. (There is a surprising number of non-engineers in any bureaucratic body.) Regards, Joachim -- Please don't send unsolicited ads.