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_20,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 109fba,99e2dadd49ce1936 X-Google-Attributes: gid109fba,public X-Google-Thread: 103376,99e2dadd49ce1936 X-Google-Attributes: gid103376,public X-Google-Thread: 107d55,99e2dadd49ce1936 X-Google-Attributes: gid107d55,public X-Google-Thread: 1108a1,99e2dadd49ce1936 X-Google-Attributes: gid1108a1,public From: shapcott@wallaby.cig.mot.com (David B. Shapcott [C]) Subject: Re: Exception Handling Date: 1996/09/13 Message-ID: <51br5k$aeh@trotsky.cig.mot.com>#1/1 X-Deja-AN: 180592420 references: <323750EA.167E@maths.usyd.edu.au> <32393072.72033128@shdgate.shd.de> organization: Cellular Infrastructure Group, Motorola newsgroups: comp.object,comp.lang.java.tech,comp.lang.c++,comp.lang.ada Date: 1996-09-13T00:00:00+00:00 List-Id: In article <32393072.72033128@shdgate.shd.de>, Felix Kasza wrote: >Robbie, > > > replies by email please, i don't read this group. > >Not feeling very sociable today, are we? > > > Where did the concept of exception handling originate ? > >I don't know -- but I do know that IBM's /360 architecture uses a >mechanism for OS calls which looks very much like a trap. PDPs used >similar features to handle illegal memory references. In the late 60s >or early 70s, I saw an APL interpreter for the PDP that expressly made >use of this although it didn't export the functionality to the >programmer (APL has no concept of an exception). I've heard that the Babbage Engine had an ingenious exception mechanism consisting of a cog and spring-loaded trip mechanism, that would activate a rod releasing a steel ball-brearing down a raceway. The weight of the ball bearing was the value of the exception being thrown (for some time, Babbage had actually considered a throwing arm mechanism, but found that his mechanism could not be made accurate -- but this does provide an interesting historical account for the phrase `throwing an exception'). -- D. Brad Shapcott [C] Contractor, Motorola Cellular Infrastructure Group