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From: mac@eleazar.dartmouth.edu (Alex Colvin)
Newsgroups: comp.os.misc
Subject: Re: Call Gates vs. traps
Message-ID: <1991Apr6.125424.12452@dartvax.dartmouth.edu>
Date: 6 Apr 91 12:54:24 GMT
References: <1991Apr3.073617.1167@ibmpcug.co.uk> <1991Apr05.083038.21124@kithrup.COM> <efeustel.670873106@tiger1>
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Call gates don't require modification of the operating system - anyone
can publish their gates.  Gates support more of a peer-peer call
interface.

Traps are usually fixed in hardware & owned by the OS.  Defining a trap
consumes a global resource.  Traps support user/kernel calls.

On systems with protection the set of traps is usually fixed.  On
systems without, such as PCs & Macs, there are often conflicts over who
uses which trap.