From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271699AbTG2Mtb (ORCPT ); Tue, 29 Jul 2003 08:49:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271700AbTG2Mtb (ORCPT ); Tue, 29 Jul 2003 08:49:31 -0400 Received: from 81-2-122-30.bradfords.org.uk ([81.2.122.30]:1920 "EHLO 81-2-122-30.bradfords.org.uk") by vger.kernel.org with ESMTP id S271699AbTG2Mta (ORCPT ); Tue, 29 Jul 2003 08:49:30 -0400 Date: Tue, 29 Jul 2003 13:59:41 +0100 From: John Bradford Message-Id: <200307291259.h6TCxfC3000230@81-2-122-30.bradfords.org.uk> To: helgehaf@aitel.hist.no, jamie@shareable.org Subject: Re: The well-factored 386 Cc: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > I didn't realise he was talking about an x86 emulator. I thought he > > was analyzing real hardware. > > > > The one thing that made it on-topic for me was his quiet suggestion > > that "forreal" mode interrupts are faster, and that it might, perhaps, > > be possible to modify a Linux kernel to run in that mode - to take > > advantage of the faster interrupts. > > That would have to be a kernel for very special use. The "forreal" > mode has protection turned off. As far as I know, that > means any user process can take over the cpu as if > it was running in kernel mode. > > Perhaps useful for some embedded use with only a couple well-tested > processes running. Still, a programming error could overwrite > kernel memory instead of segfaulting. Anything that's single user and non-networked isn't beyond the realms of feasability - it would be useful for a games console, or high performance graphics work. It would be an interesting project, but what concerns me is how well implemented these non-standard modes actually are. It's possible that there are processors out there that don't work reliably with them, or don't implement them at all. John.