From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (qmail-queue invoked by uid 0); 1 Aug 1996 16:58:39 -0000 MBOX-Line: From raman@adobe.com Thu Aug 1 18:56:34 1996 Received: (qmail-queue invoked by uid 504); 1 Aug 1996 16:50:39 -0000 Received: (qmail-queue invoked from smtpd); 1 Aug 1996 16:49:47 -0000 Received: from mail-relay-1.mv.us.adobe.com (130.248.1.1) by goldfish.cube.net with SMTP; 1 Aug 1996 16:49:44 -0000 Received: by mail-relay-1.mv.us.adobe.com; id JAA01795; Thu, 1 Aug 1996 09:49:30 -0700 Received: by labrador.mv.us.adobe.com; id JAA03301; Thu, 1 Aug 1996 09:49:29 -0700 Date: Thu, 1 Aug 1996 09:49:29 -0700 Message-Id: <199608011649.JAA03301@labrador.mv.us.adobe.com> To: jmills@siberia.gtri.gatech.edu (John M. Mills) Cc: blinux-list@goldfish.cube.net, kjahds@khjads.com Subject: Beeping LILO (Was: Re: Booting Linux) In-Reply-To: <199608011437.KAA18915@siberia.gtri.gatech.edu> References: <199608011437.KAA18915@siberia.gtri.gatech.edu> Reply-To: raman@adobe.com From: "T. V. Raman" X-Phone: 1 (415) 962-3945 X-Fax: 1(415) 962-6063 List-Id: Sometimes I get the feeling that people on this list are not taking time to absorb the answers people have already given. The "making lilo beep" thread is a case in point. I'm reposting an excellent message on this topic (not posted by me originally --credits go to original author) that in my opinion should have been the end of story on this issue. From: doyons@JSP.UMontreal.CA (Stephane Doyon) To: Chris Foote , blinux-list@goldfish.cube.net Subject: Re: Booting Linux Date: Thu, 25 Jul 1996 23:05:07 -0400 Some hints about booting Linux and reading boot messages - Finding out when the LILO boot prompt is on: It is easy to just hold down the left shift key when the computer boots, but the only way to make sure you have reached the "boot" prompt is to listen to the HD and wait. Well here are two tricks. One of the things LILO can do, is print a customized message before giving the prompt (that is the "boot" prompt, not the "LILO" prompt). Just put a line in your lilo.conf that looks like: message = /boot/message and put your customized message in /boot/message. The interesting thing is that if that file contains an ASCII 7 character (control-G), you will here a short beep when the message is actually printed by LILO. So when you hear that beep, you know you can release the shift key and type in your command line. Another thing LILO can do, is print all its stuff to a com port, so you can read it on an attached serial terminal. Just put a line in your lilo.config like serial = 1,9600n8 - Reading kernel boot-time messages: On a running system, pretty much every thing is in the log in /var/adm/something... But for a buggy system, or for installing a new system, that's another story. Two things you can do. First, you can, as someone suggested, redirect the console to a serial port, and read all messages on an attached serial terminal. I have done it in the past (a long time ago though). Here's how to do it, if I remember correctly. On your Linux partition or on your root disk, do: cd /dev rm console mknod console c 4 64 # 4,64 are the major and minor for ttyS0 #alternatively: mknod console c 4 65 # for ttyS1. I haven't done that in quite a while, so I might be forgetting something, or getting something wrong. I don't remember if it will come at you at 9600 or 38400... Perhaps someone would care to try it out... Only problem is, of course, now you might not have any screen output anymore (I don't think I ever had a sighted person tell me what happens), so it might be hard to put it back. Before you try this, make sure you can login safely either from a network or from the other com port. To put back the console device, just cd /dev rm console ls -l tty0 # it's the same as console, so you can find the numbers there # if you forget mknod console c 4 0 chmod 622 console It's useful when you really have to find out what it says on the screen. Of course you have to be able to get to /dev and have rm and mknod and ls and such working. But it can be useful when you prepare a root disk to install a new machine. FInally, I'd like to point out that any access program that works by grabbing the screen contents from the console driver (interfacing through the /dev/vcs* devices) can potentially allow you to read all messages printed to the screen since boot, even the initial BIOS print out! BRLTTY uses this scheme, so I know it can be done because I have done it several times. BRLTTY runs in user space, so I have to wait for it to be started (from my rc.S). But once it's there, I can use the scrollback feature of the console driver, which is available if you have extra RAM on your video card (like any SVGA card). Just press shift+pgup and shift+pgdn to skim through the buffer. Unless the buffer has overflowed from all boot messages (which has never been the case for me) you can scroll back up even before the console driver starts. You'll see the LILO prompt and above it the BIOS initial print out. Hope any of this helps -- Stephane Doyon Bacc. specialise en informatique doyons@IRO.umontreal.ca Universite de Montreal doyons@JSP.umontreal.ca A quote from StarTrek: Virtue is a relative term. -- Spock, "Friday's Child," stardate 3499.1. -- Best Regards, --raman Adobe Systems Tel: 1 (415) 962 3945 (B-1 115) Advanced Technology Group Fax: 1 (415) 962 6063 (E 1-160) 1585 Charleston Road Email: raman@adobe.com Mountain View, CA 94039 -7900 raman@cs.cornell.edu http://www-atg/People/Raman.html (Internal To Adobe) http://www.cs.cornell.edu/Info/People/raman/raman.html (Cornell) Disclaimer: The opinions expressed are my own and in no way should be taken as representative of my employer, Adobe Systems Inc. ____________________________________________________________________________