Re: Reboot from protected mode

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#166

From: Rich Wells
Date: Fri, 31 Jul 1992 15:14

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In article <1992Jul30.115954.12123@donau.et.tudelft.nl> cornet@zen.et.tudelft.nl (Jan-Pieter Cornet) writes:
>
>On a 286, the fastest way to get out of protected mode is to cause a triple
>fault resulting in a shutdown, which (non-buggy ;) external circuitry
>converts to a reset almost immediately (the keyboard chip takes quite a
>while to perform the reset, that's why the HLT; JMP loop is there, and
>that's why this method is faster).
>
>You can cause a triple fault by lowering the IDT limit to 0, and cause
>an exception, for example by doing MOV AX,[FFFF].

Is this the technique that Microsoft used for the original version of
OS/2?  I remember reading that they had some really neat way to re-enter
real mode from protected mode, but they wouldn't divulge the details
at the time.

Technical Details

Message-ID: <1992Jul31.151404.23530@cdsmn.mn.org>

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References: <sankey.711008151@unixg.ubc.ca> <1992Jul29.221323.9051@uoft02.utoledo.edu> <1992Jul30.115954.12123@donau.et.tudelft.nl>

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Newsgroups: comp.os.msdos.programmer
Path: arc1-ca.pugleaf.net!sparky!uunet!usc!sol.ctr.columbia.edu!The-Star.honeywell.com!umn.edu!mmm.serc.3m.com!pwcs!cdsmn!wells
From: wells@cdsmn.mn.org (Rich Wells)
Subject: Re: Reboot from protected mode
Message-ID: <1992Jul31.151404.23530@cdsmn.mn.org>
Reply-To: wells@cdsmn.UUCP (Rich Wells)
Organization: Dicomed, Inc., Burnsville, MN
References: <sankey.711008151@unixg.ubc.ca> <1992Jul29.221323.9051@uoft02.utoledo.edu> <1992Jul30.115954.12123@donau.et.tudelft.nl>
Date: Fri, 31 Jul 92 15:14:04 GMT
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