From owner-freebsd-questions Tue May 11 20:25:48 1999 Delivered-To: freebsd-questions@freebsd.org Received: from cygnus.rush.net (cygnus.rush.net [209.45.245.133]) by hub.freebsd.org (Postfix) with ESMTP id AB0FB150E7 for ; Tue, 11 May 1999 20:25:46 -0700 (PDT) (envelope-from bright@rush.net) Received: from localhost (bright@localhost) by cygnus.rush.net (8.9.3/8.9.3) with SMTP id WAA21823; Tue, 11 May 1999 22:48:24 -0500 (EST) Date: Tue, 11 May 1999 22:48:22 -0500 (EST) From: Alfred Perlstein To: James Kalmadge Cc: Gurudatt Shenoy , freebsd-questions@FreeBSD.ORG Subject: Re: 486 kernel works for 586? In-Reply-To: <3738E1C2.E088A614@banet.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 11 May 1999, James Kalmadge wrote: > > On Tue, 11 May 1999, Gurudatt Shenoy wrote: > > > > > > > > Hello, > > > I compiled the FreeBSD 2.2.1 kernel on a Pentium class CPU with the CPU > > > type set to "I486_CPU". However, when I boot the machine and try to use > > > this kernel, I get "CPU class unknown" error. > > > Won't a 486 kernel work on a "586" type CPU? > > > > > > I'd appreciate any feedback. Please reply to my email address - I am not > > > on the FreeBSD list. > > > > > > > MUST have the CPU type that you are going to use compiled in, there > > is no "forward/backward compatibility" it just must have that type of > > CPU compiled in. > > To clarify: I guess you are saying that if you compile for multiple > CPU types you're all set. Yes? > As per: > > cpu "I486_CPU" > cpu "I586_CPU" > cpu "I686_CPU" > > in the conf file. Yup, it is important to note that taking out "I386_CPU" is VERY important, it makes a lot of the kernel's lowest routines faster. I'm unsure about I486, but if you can, I'd suggest removing it as well. -Alfred To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message