Path: utzoo!attcan!uunet!wuarchive!emory!att!cbnewsl!cbnewsk!dez
From: dez@cbnewsk.att.com (daniel.e.zuccarelli)
Newsgroups: comp.os.os2.programmer
Subject: Re: DOS driver under OS/2
Keywords: device driver
Message-ID: <1990Nov15.160926.5036@cbnewsk.att.com>
Date: 15 Nov 90 16:09:26 GMT
References: <478@epicb.com>
Distribution: na
Organization: AT&T Bell Laboratories
Lines: 27

In article <478@epicb.com>, steves@truevision.com (Steve Spicklemire) writes:
> Help!
> 
> I wrote a DOS installable device driver and would like to make
> it usable under OS/2. (I don't know anything about OS/2 expect that
> there is some DOS capability, DOS in a window?) Someone told me
> that OS/2 doesn't support IOCTL read and write! Is this true?
> What happens when a DOS program in an OS/2 window generates an
> int 21 for IOCTL read or write? Is there a good reference for
> writing device drivers for OS/2 that can run, or at least be 
> compatable with drivers for DOS?
> 
> Steve Spicklemire		(steves@truevision.com	internet)
> 				(sspickle@INSTEPS.bitnet bitnet)

Can't do it. A DOS program that runs in the compatibility box will run
correctly if it makes int 21 calls.  Whether IOCTL is supported depends
on your driver.  However you must rewrite your drvier for OS/2, and it
must be a bi-modal (both real and protected mode) driver if you plan
on calling it from the DOS box (which runs in real mode).  Basically,
the bimodal requirement means switching the processor to/from real
mode when necessary, ie. processing interrupts.
-- 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
"Well, there's not much to see really. We're inside a Chinese dragon."
Dan Zuccarelli - AT&T Bell Labs CB/RV, INTERACTIVE Systems Corp.
(614) 860-7023