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Date:      Tue, 18 Jan 2005 20:19:34 +0000
From:      Steven Smith <sos22@cantab.net>
To:        Street Chaman <street_chaman@hotmail.com>
Cc:        sos22@srcf.ucam.org
Subject:   Re: Kernel mode programming -precisions
Message-ID:  <20050118201934.GB7786@archibold>
In-Reply-To: <BAY15-F6A965C17D8FF205AB06FC998F0@phx.gbl>
References:  <BAY15-F6A965C17D8FF205AB06FC998F0@phx.gbl>

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> When CPU is waiting on some new data, he cannot preform any other=20
> operation, and freezes data manipultion; that's why I'm looking for a new=
=20
> way to in/output the soft...
You may want to look at select(2) and poll(2).  Those allow you to
check whether input is available on a given file descriptor without
having to block if it isn't.

> I've found out in syscall.master the aio_read/write call. Man page says=
=20
> operation is asynchronous, so it returns quite immediatly after enqueuing=
=20
> the io thread. Could that be a solution ?
Yes, but it sounds a little like overkill for what you're talking
about.

> Or back to kernel module (by the way: is it possible to write on in
> assembly) ?
Yes, absolutely, but it's quite an unusual thing to do.  It'd be far
more common to write most of the module in C with a few little bits of
assembly in really critical parts.

Steven.

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