From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 27 Jan 2001 15:48:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 27 Jan 2001 15:48:20 -0500 Received: from neon-gw.transmeta.com ([209.10.217.66]:4613 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Sat, 27 Jan 2001 15:48:13 -0500 Message-ID: <3A7333FF.AA813685@transmeta.com> Date: Sat, 27 Jan 2001 12:47:59 -0800 From: "H. Peter Anvin" Organization: Transmeta Corporation X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.0 i686) X-Accept-Language: en, sv, no, da, es, fr, ja MIME-Version: 1.0 To: Rogier Wolff CC: "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: Linux Post codes during runtime, possibly OT In-Reply-To: <200101271020.LAA22568@cave.bitwizard.nl> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rogier Wolff wrote: > > H. Peter Anvin wrote: > > Followup to: <3A709E99.25ADE5F6@echostar.com> > > By author: "Ian S. Nelson" > > In newsgroup: linux.dev.kernel > > > > > > I'm curious. Why does Linux make that friendly 98/9a/88 looking > > > postcode pattern when it's running? DOS and DOS95 don't do that. > > > > > > I'm begining to feel like I can tell the system health by observing it, > > > kind of like "seeing the matrix." > > > It output garbage to the 80h port in order to enforce I/O delays. > > It's one of the safe ports to issue outs to. > > Yes, because it is reserved for POST codes. You can get "POST > debugging cards" that simply have a BIN -> 7segement encoder and two 7 > segment displays on them. They decode 0x80. That's what it's for. > Again, if you want to change it, find another safe port, test the hell out of it, an *PUBLICIZE IT* so noone will use it in the future. -hpa -- at work, in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/