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From: Lars Poulsen <lars@beagle-ears.com>
Newsgroups: comp.arch
Subject: Re: except what, is Vax addressing sane today
Date: Sun, 22 Sep 2024 09:14:04 -0700
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On 9/21/2024 3:14 PM, John Levine wrote:
> According to MitchAlsup1 <mitchalsup@aol.com>:
>> In the days before <good> branch prediction having a conditional branch
>> after each instruction that could have an execution problem was an
>> extremely poor choice. Thus, exceptions were invented (circa 1958).
> 
> Oh, it was worse than that.  There were instructions like "Divide or
> Halt" which stopped the computer with an error light on a zero divide.
> 
>> Many (most, nearly all) processor architectures have notoriously
>> bad exception delivery to a point of control that can deal with
>> the problem at hand.
> 
> Some of us remember imprecise itnterrupts and the OS/360 S0C0
> completion code.
> 
> But you are in general right, it makes more sense to keep the computer
> running in the normal case and provide slow ways to recover from
> failures and do something else.

 From a programmer's perspective, VAX exception handling was very nice. 
It may have been high overhead, though.