From owner-freebsd-arch  Tue Feb 27 20:19:39 2001
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Date: Tue, 27 Feb 2001 20:18:47 -0800
From: Julian Elischer <julian@elischer.org>
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To: Kostas Magoutis <magoutis@eecs.harvard.edu>
Cc: freebsd-arch@freebsd.org
Subject: Re: Logical device instances
References: <200102280048.f1S0m9n09106@wally.eecs.harvard.edu>
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Kostas Magoutis wrote:
> 
> I am writing a device driver for a user-level networking card.  User
> level code interacts with it via open, close, mmap, and ioctl.  A
> separate logical instance of the device needs to be created each time
> a process opens the device (as in when a file is created when a vnode
> is opened).  The device driver needs to have a way to find out on what
> logical instance of the device a system call is performed.  It seems
> to me that at present (with either specfs or devfs), the device driver
> has no way to find out on what opened instance of the device an
> operation is performed.  Am I missing something or the present device
> driver interfaces just don't support such functionality?
> Thanks,
> 
> Kostas
> 
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device drivers for networking don't use the 
open/close/read/write interface.
they use sockets, so that different processs open differnt sockets 
which are multiplexed onto the device using a protocol.

-- 
      __--_|\  Julian Elischer
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    (   OZ    ) World tour 2000-2001
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