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=0.6 required=5.0 tests=BAYES_05,INVALID_DATE autolearn=no autolearn_force=no version=3.4.4 Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.ARPA Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!harvard.harvard.edu!uucp%ihnp4.UUCP From: uucp%ihnp4.UUCP@HARVARD.HARVARD.EDU (UUCP Admin) Newsgroups: net.lang.ada Subject: Warning From uucp Message-ID: <8510171659.AA16125@py.garage.packard.DK> Date: Thu, 17-Oct-85 12:54:50 EDT Article-I.D.: py.8510171659.AA16125 Posted: Thu Oct 17 12:54:50 1985 Date-Received: Sat, 19-Oct-85 04:40:28 EDT Sender: daemon@ucbvax.ARPA Organization: The ARPA Internet List-Id: We have been unable to contact machine 'delftcc' since you queued your job. delftcc!mail sam (Date 10/14) The job will be deleted in several days if the problem is not corrected. If you care to kill the job, execute the following command: uustat -kdelftccN14fa Sincerely, ihnp4!uucp ############################################# ##### Data File: ############################ >From seismo!harvard!USC-ECLB.ARPA:INFO-ADA Mon Oct 14 16:57:50 1985 remote from ihnp4 Received: by ihnp4.ATT.UUCP id AA03469; 14 Oct 85 16:57:50 CDT (Mon) Received: from harvard.ARPA (HARVARD.HARVARD.EDU) by seismo.CSS.GOV with SMTP; Mon, 14 Oct 85 06:42:45 EDT Received: from USC-ECLB.ARPA by harvard.ARPA; Mon, 14 Oct 85 06:43:35 EDT Return-Path: Received: from UCB-VAX.ARPA by USC-ECLB.ARPA; Tue 8 Oct 85 01:38:20-PDT Received: by UCB-VAX (5.28/5.12) id AA20989; Tue, 8 Oct 85 00:30:39 PDT From: ihnp4!seismo!ucb-vax.Berkeley.EDU!harvard!uwvax!pokey!dan Date: 7 Oct 85 15:05:08 GMT Organization: U of Wisconsin CS Dept Subject: bug-free programs Message-Id: <260@pokey.UUCP> Precedence: junk Sender: ihnp4!seismo!harvard!ucb-vax.Berkeley.EDU:usenet Errors-To: ihnp4!seismo!harvard!ucb-vax.Berkeley.EDU:usenet To: UCB-VAX.Berkeley.EDU!info-ada Resent-Date: Sun 13 Oct 85 15:47:28-PDT Resent-To: USC-ECLB.ARPA!info-ada Resent-Message-Id: <12150885483.35.INFO-ADA@USC-ECLB.ARPA> For anyone who is used to reading the horror stories in Software Engineering News, the idea of bug-free large programs is a bit hard to grapple with. Large programs are so complex, and have so many states, that exhaustive testing would take hundreds or thousands of years. Even in the unlikely event that you do have a mechanical proof system, that system is vulnerable to the input and output predicates for a given code fragment. The important thing about Ada exceptions is that they include the ability to trap constraint and range violations like the one which would supposedly appear on the pilot's display. Proper coding standards will enforce the creation of programs in which these (unlikely but possible) errors would be trapped and dealt with in an orderly way. Sure beats the heck out a C program that goes off the end of an array and fires your ejection seat . . . -- Dan