From owner-freebsd-smp Tue Nov 19 17:35:33 1996 Return-Path: owner-smp Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id RAA22805 for smp-outgoing; Tue, 19 Nov 1996 17:35:33 -0800 (PST) Received: from clem.systemsix.com (clem.systemsix.com [198.99.86.131]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id RAA22773 for ; Tue, 19 Nov 1996 17:35:24 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by clem.systemsix.com (8.6.12/8.6.12) with SMTP id SAA21266; Tue, 19 Nov 1996 18:35:06 -0700 Message-Id: <199611200135.SAA21266@clem.systemsix.com> X-Authentication-Warning: clem.systemsix.com: Host localhost didn't use HELO protocol X-Mailer: exmh version 1.6.5 12/11/95 From: Steve Passe To: Barney Wolff cc: freebsd-smp@freebsd.org Subject: Re: reinventing vs copying In-reply-to: Your message of "Tue, 19 Nov 1996 17:43:00 EST." <32923fad0.15a6@databus.databus.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 19 Nov 1996 18:35:06 -0700 Sender: owner-smp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Hi, > I'd like to understand better than I do (which is hardly at all) why it > seems (to me) as though all the SMP work is being done without reference > to what other SMP-capable OS's do. good question. --- > I do understand that code cannot be copied, certainly from the > commercial systems and not even from Linux without complying with the > GPL, but what prevents the borrowing of ideas or even the discussion > of how common problems are handled by other, seemingly working, > implementations? nothing, we sometimes do. In some cases the internals of the systems differ so greatly that what works for one won't for the other. For example, Terry posted a rather detailed discussion of another OS's method for handling INTs, and how it would resolve the "missing INT" problem of the IO APIC. But the methods used are so far from the FreeBSD kernel as to be unusable for us. More than anything it is just that we don't run in those circles. --- > Is it that the information is not available, or has it > been the experience that the other systems don't really solve the > problems that are showing up? I don't have access to info about systems like NT or Solaris. I've done a little looking at Linux code in the past. I suppose I should grab a complete Linux SMP kernel, anyone know what the definative version would be? --- > Or is it that a more-or-less clean-room > implementation is being attempted to avoid even the suspicion of theft? that certainly ain't it! --- I personally am doing this work for both fun and to increase my knowledge in areas that are important to my career. I find that "inventing" solutions fills both those needs. When someone starts paying me to do this I might worry about being more "efficient". I'm not suggesting that people shouldn't bring in ideas from other OS's when appropriate, its just not my first approach to solving problems in this context. Another important thing to realize is that this project is more or less run by anarchy! If you see a better way of getting things done SPEAK UP. We need testers. We need coders. We need researchers. We need to get more people involved if this project is going to go anywhere!!! -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD