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,da26f7e99d6cfcf3 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-04-10 20:32:08 PST Path: supernews.google.com!sn-xit-03!supernews.com!nntp.cs.ubc.ca!newsfeed.stanford.edu!feed.textport.net!newsranger.com!www.newsranger.com!not-for-mail Newsgroups: comp.lang.ada From: Ted Dennison Sender: usenet@www.newsranger.com References: <9Pxz6.992$ix4.198187@news1.rdc1.sfba.home.com> <4ZmA6.1693$Ak1.181271@newsread2.prod.itd.earthlink.net> Subject: Re: software failure question Message-ID: Date: Tue, 10 Apr 2001 15:39:35 GMT NNTP-Posting-Host: 209.208.22.130 X-Complaints-To: abuse@newsranger.com X-Trace: www.newsranger.com 986917175 209.208.22.130 (Tue, 10 Apr 2001 11:39:35 EDT) NNTP-Posting-Date: Tue, 10 Apr 2001 11:39:35 EDT Organization: http://www.newsranger.com Xref: supernews.google.com comp.lang.ada:6731 Date: 2001-04-10T15:39:35+00:00 List-Id: >In article <4ZmA6.1693$Ak1.181271@newsread2.prod.itd.earthlink.net>, Phaedrus >says... >> >>I'm reminded of another famous software failure, that may or >>may not be an urban legend: >>According to the story, when programming a helicopter simulation >>for the Australian military, someone noticed that they didn't have >>any kangaroos. Rather than write a whole bunch of new code to >>simulate them, they just derived a new subclass from the class that >>they used to simulate the ground troops. I forgot about this part. The OO mumbo-jumbo that got thrown in here was just made up. They were interfacing their virtual sim to another simulation capable of generating and controlling other entities (perhaps MODSAF). When this is done, each entity MODSAF is controlling needs to be mapped on the virtual sim to an entity that the virtual sim's image generator knows how to render. Its fairly common in such a setup to map one entity to another similar one that MODSAF (or whatever they are using) doesn't have. I've been on two different projects that did this. There's nothing particularly OO about it. But the story has slowly mutated itself into some kind of unspecified object lesson on the dangers of OO programming. Go figure. To put my previous post in perspective, they weren't expecting SAMs to come out of MODSAF, so they didn't set up a mapping for them. That meant they got the default mapping, which happened to be multicolored beach balls. :-) BTW: I've personally seen a (simulated) marine helocopter fly in close formation with a heap of rubble for over thirty minutes due to a similar issue. We had them keep flying that long so we could monitor the network traffic and try to figure out where the bug was. The pilots entertained themselves during this time by pretending that the squarish rubble heap was a Borg ship. :-) --- T.E.D. homepage - http://www.telepath.com/dennison/Ted/TED.html home email - mailto:dennison@telepath.com