From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Althoff Message-ID: <620180968.20030715140735@tiscali.co.uk> To: Rob Ristroph <9fans@cse.psu.edu> Subject: Re: [9fans] Plan 9 install doesn't put the right MBR on the disk In-Reply-To: <87vfu4mkqw.fsf@rgristroph-austin.ath.cx> References: <87vfu4mkqw.fsf@rgristroph-austin.ath.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Tue, 15 Jul 2003 14:07:35 +0100 Topicbox-Message-UUID: f8b93b5c-eacb-11e9-9e20-41e7f4b1d025 Hello Rob Ristroph I'll join in on that experience. 2 main boards, 3 hdd's tested. I previously posted about partdisk being greedy... Hours of install atempts later.... Replicateable steps and work around: (with the aid of TomsRTBT linux 2.88 on CD) 1. Cleanup boot Linux (I use TomsRtbt), execute dd if=/dev/zero of=/dev/hda bs=1k count=10000 Zeroing just the mbr (bs=512 count=1) leads to the side effect later if the same partitions are created again, plan9 fdisk will find the old partitions. So the count value clobbers a bit more. Beware if you have other partitions!!!!! Does anyone know where plan9 keeps the "sub partitions info so I could kill that more "point blank"?? Then again prepdisk should not pick up historic entries... 2. partitions if you go to plan9 it cannot create partitions properly (as the others described: In my case creating a partition less than the total hdd size, resulted in the installer going back to partdisk. Inspecting what it had done from Linux fdisk, I found a partion entry which had the proper boundaries, but type set to "0". I tried lots of variants of that theme none worked. Even giving it the whole disk (20GB) is useless since the MBR does not work. Other fdisks (non plan9) cough up about the format of the entries at times. Soooo.... stay in Linux In Linux fdisk: create a new, blank partition table if working on a zeroed disk. Write that. Now create the partions for plan9 that you need. fdisk will set them to type 82 (linux) change that to type 39 (plan9, which fdisk knows) Write. Finished. 2b. You did not zero the disk since you are keeping other partitions: use Linux fdisk to create the partitions anyhow. It works. Don't rewrite the MBR from Plan9. 2c. using DOS fdisk /mbr creates a MBR that is only good for 2GB partitions. 3. Plan9 will be happy now continue with prepdisk, creating fs, swap,... It will see the partition you have created and set to type 39 All the best, Martin martin.althoff@tiscali.co.uk Written Tuesday, July 15, 2003 at 13:47:39 <<<<<================>>>>> Tuesday, July 15, 2003, 6:17:43 AM, you wrote: > Hi, > The current Plan 9 which you download from Bell Labs is > uninstallable on a clean machine. It doesn't put the Master > Boot Record on the disk during the install process, and > various methods of writing an mbr (from another OS or from a > Plan 9 floppy) make the boot process survive only a split > second longer. > Note that if you currently have a working Plan 9 on the disk, > you have to wipe the MBR to replicate this problem. You can > do this by booting a dos disk and doing fdisk /mbr or with > dd. If you don't, you will install the latest Plan 9 and > it will seem to work fine, but only because the MBR survived > from your previous working setup. > I have replicated this behaviour on two computers of my own, > and even bought a brand new disk because I thought all my > disks might be screwed; and on top of that I went to friend's > house today and convinced him to take down his working Plan 9 > and try a fresh install on a clean disk, and replicated it > there also. > --Rob