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Date: Tue, 15 Oct 1996 12:25:35 -0700
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Subject: Re: device driver open/close inconsistency
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Poul-Henning Kamp wrote:
> 
> Why do we call a device-driver->open() on all opens, but only ->close()
> once on the last close ?
> 
> --
> Poul-Henning Kamp           | phk@FreeBSD.ORG       FreeBSD Core-team.
> http://www.freebsd.org/~phk | phk@login.dknet.dk    Private mailbox.
> whois: [PHK]                | phk@ref.tfs.com       TRW Financial Systems, Inc.
> Future will arrive by its own means, progress not so.

history?

the call on last close 
semantic has been a part of Unx for a long time
and takes into account that FORK'd processes would call it twice
and have only called the open once.....