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-Thread: 103376,cfc5097715e8ed04 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news3.google.com!news1.google.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Peter Amey Newsgroups: comp.lang.ada Subject: Re: n versioning is there any other better approach Date: Mon, 24 Apr 2006 00:31:02 +0100 Message-ID: <4b2h1rFvb6o3U1@individual.net> References: <1145599506.289672.274530@u72g2000cwu.googlegroups.com> <7cWIiIwG$u01@eisner.encompasserve.org> <25f2g.111486$oL.37868@attbi_s71> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: individual.net wNSutLJMBkAIT48Nrpm9rAYlwWsnIlYr32gj9GnsyWH2MEnpM= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax) X-Accept-Language: en-us, en In-Reply-To: Xref: g2news2.google.com comp.lang.ada:3904 Date: 2006-04-24T00:31:02+01:00 List-Id: Jeffrey R. Carter wrote: > Larry Kilgallen wrote: > >> >> Do you recall whether there was any commonality in the versions, other >> than the specification ? Like language, background of implementers, >> deadline, etc. ? > > > Sorry, no, just that the versions were developed independently. > Are you perhaps thinking of the Knight-Leveson experiment? The paper is on line somewhere. ISTR that they got teams of students independently to implement the same specification. The interesting result is that the programs all tended to fail the same, hard, test cases - e.g. area of a figure in the case where all the vertices were 0,0 or intersection of lines that are parallel. The conclusion was that N version gives some protection from random errors but that real errors aren't very random! Peter