From owner-freebsd-chat Wed Feb 13 20:58:35 2002 Delivered-To: freebsd-chat@freebsd.org Received: from albatross.prod.itd.earthlink.net (albatross.mail.pas.earthlink.net [207.217.120.120]) by hub.freebsd.org (Postfix) with ESMTP id 56F9F37B402 for ; Wed, 13 Feb 2002 20:58:32 -0800 (PST) Received: from pool0463.cvx21-bradley.dialup.earthlink.net ([209.179.193.208] helo=mindspring.com) by albatross.prod.itd.earthlink.net with esmtp (Exim 3.33 #1) id 16bDyA-0000Oj-00; Wed, 13 Feb 2002 20:58:06 -0800 Message-ID: <3C6B43D3.39B7011F@mindspring.com> Date: Wed, 13 Feb 2002 20:57:55 -0800 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 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> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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 wrote: > 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? Most of the "breakthrough" designs we see happening in BSD today have been discussed in CS literature in the academic world at least 10-12 years ago. Some of the "breakthroughs" are "only" 5 or 6 years old. The polling code Luigi did, for example, was beased on a Jaff Mogul paper from 1991. My own code for LRP was based on a paper from Rice University by Mohit Aron's group, and is 6 years old. It took since FreeBSD 2.2 to integrate an implementation of FACK/SACK into FreeBSD; that's 8 years. Most cutting edge CS work occurs in academia, in very small groups, with no more than 4 people participating, and usually, a single idealist leading the group. Other things which appear to be "breakthroughs" are just concessions to hardware tradeoffs that are true today that weren't true when the original implementations were first deployed (e.g. relative cost of disk seeks vs. speed on tracks, relative costs of main memory access vs. cache access, etc.). Revisiting these tradeoffs is normal and doesn't really count as "breakthrough" in my book. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message