From owner-freebsd-hackers  Wed Nov  8 13:16:48 2000
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Date: Wed, 08 Nov 2000 13:16:00 -0800
From: Julian Elischer <julian@elischer.org>
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To: Terry Lambert <tlambert@primenet.com>
Cc: Mike Smith <msmith@FreeBSD.ORG>,
	bruno schwander <bschwand@dvart.com>, freebsd-hackers@FreeBSD.ORG
Subject: Re: close call in a device ?
References: <200011082035.NAA25463@usr08.primenet.com>
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Terry Lambert wrote:
> 
> > If I understand you correctly, you have multiple processes all of which
> > are going to try to open /dev/foo, and you want them to behave as though
> > they have each opened a unique device?
> >
> > You can't do this with FreeBSD, or with many other Unixes.
> 
> Any SVR4 system can support this.  So can AIX.
> 
> > Arguably, this is a defect with the device model.  If you are trying to
> > fake up concurrent access to a device, and the client processes are only
> > going to read and write (no ioctls) to this device, then you can use a
> > fifo and a multiplexor process.
> >
> > Alternatively, and this would be recommended; fix the client program.
> 
> Or fix the device model.  You can't have multiple VMWARE sessions
> in FreeBSD today because of this defect in the device model.

I believe that this is not the reason..
it's another resource that we only have globally.. (i.e. once) but I
forget what it is..

the problem here can be solved by using Poul's 'cloning device' 
interface in the driver.
I don't think he has it quite completed but it is partly there.. maybe
enough..


only in -current at the moment and you need to have devfs turned on.

each time you open it, you actually get a different device and  vnode..
> 
>                                         Terry Lambert
>                                         terry@lambert.org
> ---
> Any opinions in this posting are my own and not those of my present
> or previous employers.
> 
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-- 
      __--_|\  Julian Elischer
     /       \ julian@elischer.org
    (   OZ    ) World tour 2000
---> X_.---._/  presently in:  Budapest
            v


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