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From: efeustel@prime.com (Ed Feustel)
Newsgroups: comp.os.misc
Subject: Re: Call Gates vs. traps
Message-ID: <efeustel.670873106@tiger1>
Date: 5 Apr 91 17:38:26 GMT
Article-I.D.: tiger1.efeustel.670873106
References: <1991Apr3.073617.1167@ibmpcug.co.uk> <1991Apr05.083038.21124@kithrup.COM>
Lines: 6
Nntp-Posting-Host: tiger1

Call gates can be considerably faster than traps which may require
substantial interpretation.  We use call gates on the Prime 50 series.
When one proceeds to an inward ring, the stack changes and the access writ rights 
are changed automatically.  Depending on how much saving and interpretation is
done and on how well the call gates are implemented (not very well on the 386)
call gates can be the prefered method of implementation of system calls.