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Date:      Wed, 10 Mar 1999 14:33:26 -0500
From:      "Gary T. Corcoran" <garycor@home.com>
To:        Chuck Robey <chuckr@mat.net>
Cc:        Richard Cownie <tich@ma.ikos.com>, freebsd-hardware@FreeBSD.ORG
Subject:   Re: PCI WinModem
Message-ID:  <36E6C906.7620B804@home.com>
References:  <Pine.BSF.4.10.9903101342390.43830-100000@picnic.mat.net>

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Chuck Robey wrote:
> 
> On Wed, 10 Mar 1999, Richard Cownie wrote:
> > Economically and technically, from my (admittedly meagre) experience
> > I'd say WinModem's are a neat solution - if you only run Windows
> > (like 95%+ of users).  Don't knock it just because FreeBSD can't
> > support it (yet).
> 
> And FreeBSD isn't very likely to support it at all, because it's an
> incredible waste of computing power.  You make it sound like being
> incredibly cheap is a virtue.  The simple minded thing just offloads
> all
> the signal processing of a modem onto your processor, which means it
> can't do anything else useful while the modem's going.  

No, no.  The *signal processing* is still done on a DSP on the modem
card.  It's the "everything else" (e.g. interpreting AT commands, poking
the right modem registers at the right times, etc.) which is offloaded
to the host, and that *doesn't* really take much CPU, especially in these
days of 300, 400, 500 MHz CPUs.  You gotta remember - what was unthinkable
just a few years ago on yesteryear's CPU, is now often a "so what?".

What you were thinking of is called a "soft modem", where *everything*
(except the analog<->digital conversions which are in a small piece of
hardware) is done on the CPU.  Those require a delicate "balance" of
CPU and OS activity...  ;-)

Gary


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