From owner-freebsd-chat Wed Feb 13 15:57:52 2002 Delivered-To: freebsd-chat@freebsd.org Received: from lists.blarg.net (lists.blarg.net [206.124.128.17]) by hub.freebsd.org (Postfix) with ESMTP id 4111F37B405 for ; Wed, 13 Feb 2002 15:57:46 -0800 (PST) Received: from thig.blarg.net (thig.blarg.net [206.124.128.18]) by lists.blarg.net (Postfix) with ESMTP id D9BF2BD6E; Wed, 13 Feb 2002 15:57:45 -0800 (PST) Received: from localhost.localdomain ([206.124.139.115]) by thig.blarg.net (8.9.3/8.9.3) with ESMTP id PAA02662; Wed, 13 Feb 2002 15:57:45 -0800 Received: (from jojo@localhost) by localhost.localdomain (8.11.6/8.11.3) id g1DNwPn24075; Wed, 13 Feb 2002 15:58:25 -0800 (PST) (envelope-from swear@blarg.net) To: j mckitrick Cc: freebsd-chat@FreeBSD.ORG Subject: Re: How do basic OS principles continue to improve? References: <20020213192510.A46224@dogma.freebsd-uk.eu.org> From: swear@blarg.net (Gary W. Swearingen) Date: 13 Feb 2002 15:58:25 -0800 In-Reply-To: <20020213192510.A46224@dogma.freebsd-uk.eu.org> Message-ID: Lines: 23 User-Agent: Gnus/5.0808 (Gnus v5.8.8) XEmacs/21.1 (Cuyahoga Valley) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org j mckitrick writes: > Since VM has been around for quite a while, and since the basic > algorithms for task scheduling, page swapping, critical sections and so > on have been around for a while as well as basic computer sci theory, > what leads to the breakthrough new designs we see in BSD? Other than > SMP? If I understand the question, I'll guess that a developer sees an existing design that looks poor, either by pure reason or by its ugliness, or by comparision of it's design or performance with a similarly-purposed design in another OS or in some research report. For example, if I was a kernel hacker, I might have done something with a report I read on a school project in which the guy had a compiler inside his kernel and had it compile optimised code as needed. I didn't see or don't remember the particular techniques he used, but I suppose it was able to avoid indirect addressing or something. He had several techniques, as I recall. He reported very significant speed-ups. (But then, I'd guess that most bottlenecks are not hampered by inefficient code as much as by inefficient algorithms, but I'd like to read his report again.) Sadly, I lost the URL a couple of years ago and a quick google didn't find it. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message