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From: Bart Termorshuizen <btermors@dds.nl>
Subject: Re: Exception Handling
Date: 1996/09/18
Message-ID: <323FF7D6.72E5@dds.nl>#1/1
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references: <323750EA.167E@maths.usyd.edu.au>
 <32393072.72033128@shdgate.shd.de> <51br5k$aeh@trotsky.cig.mot.com>
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Date: 1996-09-18T00:00:00+00:00
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David B. Shapcott [C] wrote:
> 
> In article <32393072.72033128@shdgate.shd.de>,
> Felix Kasza <felixk@mailbag.shd.de> 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

Way to go!  ;)
Bart.