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Date:      Wed, 9 Aug 1995 08:37:21 +0930 (CST)
From:      Michael Smith <msmith@atrad.adelaide.edu.au>
To:        erich@lodgenet.com (Eric L. Hernes)
Cc:        msmith@atrad.adelaide.edu.au, ROBIN@ptnsct.nis.za, questions@freebsd.org
Subject:   Re: Accessing i/o map space with freebsd 2.1.0
Message-ID:  <199508082307.IAA26591@genesis.atrad.adelaide.edu.au>
In-Reply-To: <199508081516.KAA24583@jake.lodgenet.com> from "Eric L. Hernes" at Aug 8, 95 10:16:32 am

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Eric L. Hernes stands accused of saying:
> > Your program must be run as root; before performing any I/O operations,
> > open the file /dev/io.  This action grants the process priveledges to 
> > read and write directly to the hardware.
> > 
> Does this really work?

Yes.

> in /usr/src/sys/i386/i386/mem.c, it looks like it is #ifdef'ed out.

No, that's the old /dev/ioport, which provided an interface with file
semantics.  /dev/io just sets the IOPL (?) bit for the process, allowing it
to do raw IO.  Have you actually tried it?

> eric.

-- 
]] Mike Smith, Software Engineer        msmith@atrad.adelaide.edu.au    [[
]] Genesis Software                     genesis@atrad.adelaide.edu.au   [[
]] High-speed data acquisition and                                      [[
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