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From: johnl@well.UUCP (John A. Limpert)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Switching from Protected to Real Mode
Message-ID: <3813@well.UUCP>
Date: Mon, 24-Aug-87 03:25:38 EDT
Article-I.D.: well.3813
Posted: Mon Aug 24 03:25:38 1987
Date-Received: Tue, 25-Aug-87 02:15:47 EDT
References: <1387@imagen.UUCP>
Reply-To: johnl@well.UUCP (John A. Limpert)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 6
Keywords: 286
Summary: Microsoft's Hack

From what I have heard, they load the IDTR (interrupt descriptor
table register) with 0 and execute an INT 3 instruction.  This causes
multiple faults and drops the 80286 back into real mode.  I am not
sure what state this leaves you concerning segments and the prefetch
queue.  I picked this info up from someone who had gone to one of
the OS/2 seminars.