From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932126AbWDJToK (ORCPT ); Mon, 10 Apr 2006 15:44:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932128AbWDJToK (ORCPT ); Mon, 10 Apr 2006 15:44:10 -0400 Received: from khc.piap.pl ([195.187.100.11]:44040 "EHLO khc.piap.pl") by vger.kernel.org with ESMTP id S932126AbWDJToJ (ORCPT ); Mon, 10 Apr 2006 15:44:09 -0400 To: "linux-os \(Dick Johnson\)" Cc: "Andi Kleen" , "Robert Hancock" , "linux-kernel" Subject: Re: Black box flight recorder for Linux References: <5ZjEd-4ym-37@gated-at.bofh.it> <5ZlZk-7VF-13@gated-at.bofh.it> <4437C335.30107@shaw.ca> <200604080917.39562.ak@suse.de> From: Krzysztof Halasa Date: Mon, 10 Apr 2006 21:44:06 +0200 In-Reply-To: (linux-os@analogic.com's message of "Mon, 10 Apr 2006 08:18:01 -0400") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "linux-os \(Dick Johnson\)" writes: > Further, in a boot where the BIOS needs to initialize hardware, > It will write all RAM before enabling NMI. This makes sure that > the parity bit(s) are set properly. Most BIOS will attempt to > preserve RAM on a 'warm' boot as a throw-back to the '286 days > with their above-1MB-memory-manager paged RAM because the > only way to get back from protected mode to 16-bit real mode > was a hardware reset. I think there is no distinction WRT RAM test between cold and warm boot anymore. If the BIOS clears the RAM is, I think, determined by the "fast POST" option in BIOS setup (it always checks the size so some bytes will be changed anyway). > When using a memory-manager like DOS's > HIMEM.SYS, you might actually be rebooting the machine hundreds > of times per second! Yes but it uses (or, rather, used) a CMOS flag to skip POST (not only the RAM test) and to go directly to the entry point in real mode. IIRC (I may be wrong, that was 15+ years ago) only 286 required KBC reset to return to real mode (did LOADALL matter?), 386s have no such problem. BTW I understand the idea have nothing to do with actual aircraft, so it would be the admin rather than NTSB looking at the data(?). -- Krzysztof Halasa