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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,fedc2d05e82c9174 X-Google-Attributes: gid103376,public From: Marin David Condic Subject: Re: Ada 83 - Sometimes still chosen Date: 1999/03/25 Message-ID: <36FA5169.622A5196@pwfl.com>#1/1 X-Deja-AN: 458965891 Content-Transfer-Encoding: 7bit Sender: condicma@bogon.pwfl.com References: <87aex3pue4.fsf@mihalis.ix.netcom.com> <36F913E0.75F51763@lmco.com> <7dbcj3$e0l@dfw-ixnews7.ix.netcom.com> <7dbvd6$56q$1@nnrp1.dejanews.com> <7dc7tu$2uk@dfw-ixnews7.ix.netcom.com> Content-Type: text/plain; charset=us-ascii Organization: Pratt & Whitney Mime-Version: 1.0 Reply-To: diespammer@pwfl.com Newsgroups: comp.lang.ada Date: 1999-03-25T00:00:00+00:00 List-Id: Richard D Riehle wrote: > > In article <7dbvd6$56q$1@nnrp1.dejanews.com>, > robert_dewar@my-dejanews.com wrote: > > in response to my observation about the continuation of Ada 83, > > >And almost certainly it will still be Ada 95 code, seeing > >as Ada 95 is almost exactly upwards compatible with Ada 83 > > On some projects some programming managers feel it is appropriate > to freeze even the version of the compiler used to develop some > long-lived software product. That is, once the satellite is > deployed, all updates will be made using exactly the same language > and version of the compiler used for the original development. > I'd say this is true of most mission critical applications which require any significant amount of verification. And the freezing point will come far sooner than system deployment. The usual question goes like this: "If you change the compiler version, host platform, etc. and feed it the source code you gave me last week, can you guarantee that I'll get exactly the same bits out this time as I did then?" The answer is obviously "No." (It gets worse that that when you consider that it is possible to have the same compiler version, OS version, etc. and run on two different days with different loads on the system and because of dynamic memory situations, the optimizer might give you different object code. This actually happened to us once.) Once you go to the effort of expensive verification testing, you need to be able to reproduce the image precisely without disturbing anything you did not intend to modify. -- Marin David Condic Real Time & Embedded Systems, Propulsion Systems Analysis United Technologies, Pratt & Whitney, Large Military Engines M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600 ***To reply, remove "bogon" from the domain name.***