From owner-freebsd-arch Wed May 24 8:50:22 2000 Delivered-To: freebsd-arch@freebsd.org Received: from point.osg.gov.bc.ca (point.osg.gov.bc.ca [142.32.102.44]) by hub.freebsd.org (Postfix) with ESMTP id D3E8837BCB7 for ; Wed, 24 May 2000 08:50:14 -0700 (PDT) (envelope-from Cy.Schubert@uumail.gov.bc.ca) Received: (from daemon@localhost) by point.osg.gov.bc.ca (8.8.7/8.8.8) id IAA25771; Wed, 24 May 2000 08:50:00 -0700 Received: from passer.osg.gov.bc.ca(142.32.110.29) via SMTP by point.osg.gov.bc.ca, id smtpda25767; Wed May 24 08:49:47 2000 Received: (from uucp@localhost) by passer.osg.gov.bc.ca (8.9.3/8.9.1) id IAA09790; Wed, 24 May 2000 08:49:47 -0700 (PDT) Received: from cwsys9.cwsent.com(10.2.2.1), claiming to be "cwsys.cwsent.com" via SMTP by passer9.cwsent.com, id smtpdqG9788; Wed May 24 08:48:55 2000 Received: (from uucp@localhost) by cwsys.cwsent.com (8.10.1/8.9.1) id e4OFmtY22468; Wed, 24 May 2000 08:48:55 -0700 (PDT) Message-Id: <200005241548.e4OFmtY22468@cwsys.cwsent.com> Received: from localhost.cwsent.com(127.0.0.1), claiming to be "cwsys" via SMTP by localhost.cwsent.com, id smtpdl22464; Wed May 24 08:48:00 2000 X-Mailer: exmh version 2.1.1 10/15/1999 Reply-To: Cy Schubert - ITSD Open Systems Group From: Cy Schubert - ITSD Open Systems Group X-OS: FreeBSD 4.0-STABLE X-Sender: cy To: Dan Nelson Cc: Chuck Paterson , arch@FreeBSD.ORG Subject: Re: Preemptive kernel on older X86 hardware In-reply-to: Your message of "Wed, 24 May 2000 10:24:26 CDT." <20000524102426.A8590@dan.emsphone.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 24 May 2000 08:48:00 -0700 Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <20000524102426.A8590@dan.emsphone.com>, Dan Nelson writes: > In the last episode (May 24), Chuck Paterson said: > > The 386 processors do not support the locked exchange instruction. > > For these systems the locked exchange can be replaced with roughly a > > "cli, tst, cmp, branch, store, sti". > > > > The following are the obvious choices > > > > 1. Make two separate builds. > > Why not just make it conditional on the "cpu I386_CPU" line in the > kernel Makefile? The comment already reads: > > # deleting the specification for CPUs you don't need to use may make > # parts of the system run faster. This is especially true removing > # I386_CPU. > > Distribute GENERIC just like usual, and let the user remove I386_CPU > when he builds his own kerenl. ... and have the user select options to build a custom kernel just after install, the same way Tru64-UNIX does. > > > I have talked to a couple of people who think that supporting this > > older stuff won't be important to FreeBSD by the time the kernel is > > preemptive. Some even thought supporting the original Pentium > > processors might not be required. I'll propose the following as it > > I wouldn't go that far, unless you're thinking 3-4 years in the future? > There are a lot of overdrive and AMD CPUs out there that use the 486 > instruction set. 486's make good cheap firewalls. You'll probably see them in use for that and other roles for a lot longer than you think. Regards, Phone: (250)387-8437 Cy Schubert Fax: (250)387-5766 Team Leader, Sun/DEC Team Internet: Cy.Schubert@osg.gov.bc.ca Open Systems Group, ITSD, ISTA Province of BC To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message