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From: boyd@necisa.ho.necisa.oz.au (Boyd Roberts)
Newsgroups: comp.unix.internals,comp.unix.sysv386
Subject: Re: SCO UNIX *double* device driver
Message-ID: <2050@necisa.ho.necisa.oz.au>
Date: 21 Mar 91 01:27:42 GMT
Article-I.D.: necisa.2050
References: <905@zeusa.UUCP>
Organization: NEC Information Systems Australia Pty. Ltd.
Lines: 19

In article <905@zeusa.UUCP> hendrik@zeusa.UUCP (Hendrik Vermooten) writes:
>
>I need to "channel" all I/O going to and from a device, through my own
>handler routine (this routine itself uses hardware to do its job).
>

Trivial.  Write your driver so it calls the other driver through the bdevsw.
Make the appropriate devices in dev to reference your driver.  Use these
instead of the ones referencing the device you're overlaying.  Problem solved.

You may have to be a bit careful about handling wakeups to prevent the wrong
thing from happening, but it's not too hard.  Just think about it carefully.

Your driver is just a pseudo-device that manipulates another driver.


Boyd Roberts			boyd@necisa.ho.necisa.oz.au

``When the going gets wierd, the weird turn pro...''