[9fans] Plan 9 install doesn't put the right MBR on the disk

[9fans] Plan 9 install doesn't put the right MBR on the disk

[Rob Ristroph]

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

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Douglas A. Gwyn]

Rob Ristroph wrote:
>         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, ...

It has been that way for at least a month..
Whenever I install (floppy+CD) a kit from back then
I don't get a bootable Plan9 partition, and if I let
the install process modify the partition table it
wipes out my Solaris boot manager, usually making a
"bad PBR Sig" (signature?).  If I tell the installer
to make a boot floppy, the resulting floppy can't
boot the system.  This is frustrating and annoying..

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[northern snowfall]

> It has been that way for at least a month..


Yeh, it didn't bother me much last time I
did a clean installation. I'm pretty sure
something is just skipped in the inst
scripts.

I didn't feel the need to report since the
solution is very simple. To rectify the
situation I simply installed a mbr manually
via the plan9 install floppy.

It takes less than a second to do.

Don

http://www.7f.no-ip.com/~north_

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Rob Ristroph]

>>>>> "northern" == northern snowfall <dbailey27@ameritech.net> writes:
northern>
>> It has been that way for at least a month..
northern> Yeh, it didn't bother me much last time I
northern> did a clean installation. I'm pretty sure
northern> something is just skipped in the inst
northern> scripts.
northern>
northern> I didn't feel the need to report since the
northern> solution is very simple. To rectify the
northern> situation I simply installed a mbr manually
northern> via the plan9 install floppy.
northern>
northern> It takes less than a second to do.

Yes that occurred to me also; but booting from a floppy and doing
"disk/mbr" or "disk/mbr -m /386/mbr /dev/sdC0/data" did not work.  How
did you put an mbr on the harddrive ?

--Rob

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[northern snowfall]

>
>
>Yes that occurred to me also; but booting from a floppy and doing
>"disk/mbr" or "disk/mbr -m /386/mbr /dev/sdC0/data" did not work.  How
>did you put an mbr on the harddrive ?
>
Same c-line for mbr. Then I redid the partitions.

Don

http://www.7f.no-ip.com/~north_

>

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Martin Althoff]

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

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Rob Ristroph]

>>>>> "Martin" == Martin Althoff <martin.althoff@tiscali.co.uk> writes:
Martin>
Martin> 2c. using DOS fdisk /mbr creates a MBR that is only good for
Martin>     2GB partitions.

You know, that explains a lot, because now I understand how I got Plan
9 working before -- I was playing around on a small, old disk, just 2
GB big.  I was planing to re-install fresh on larger disks to
experiment with a more permanent setup when I ran into this.

--Rob

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[David Presotto]

[-- Attachment #1: Type: text/plain, Size: 213 bytes --]

I tried it on one yesterday and it put a working mbr on it.  Perhaps
I did something different.  I copied /dev/zeros to the disk before
starting to wipe out what was there.

Is it asking you to install an MBR?

[-- Attachment #2: Type: message/rfc822, Size: 3038 bytes --]

From: rgr@sdf.lonestar.org (Rob Ristroph)
To: 9fans@cse.psu.edu
Subject: [9fans] Plan 9 install doesn't put the right MBR on the disk
Date: 15 Jul 2003 00:17:43 -0500
Message-ID: <87vfu4mkqw.fsf@rgristroph-austin.ath.cx>


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

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[nofreakingspam]

David Presotto wrote:
>
> I tried it on one yesterday and it put a working mbr on it.  Perhaps
> I did something different.  I copied /dev/zeros to the disk before
> starting to wipe out what was there.
>
> Is it asking you to install an MBR?
>
>   ------------------------------------------------------------------------
>
> Subject: [9fans] Plan 9 install doesn't put the right MBR on the disk
> Date: 15 Jul 2003 00:17:43 -0500
> From: rgr@sdf.lonestar.org (Rob Ristroph)
> Reply-To: 9fans@cse.psu.edu
> To: 9fans@cse.psu.edu
>
> Hi,
>
>         The current Plan 9 which you download from Bell Labs is
>         uninstallable on a clean machine.
> . . .

Actually, the loader when on the HD seems to fail.  I use a boot floppy
made at install time and erased everything on it except 9load.  The
floppy boots, the loader goes to the HD for 9pcdisk and plan9.ini and
the system is up and running.  Someone put 9load out of its misery.

Later, Bob

--
bbourg-at-ccsi.com

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[nofreakingspam]

nofreakingspam@ccsi.com wrote:

> Actually, the loader when on the HD seems to fail.  I use a boot floppy
> made at install time and erased everything on it except 9load.  The
> floppy boots, the loader goes to the HD for 9pcdisk and plan9.ini and
> the system is up and running.  Someone put 9load out of its misery.

Wow, is my face red.  I checked on the boot sequence and 9load is
probably not the culprit.  According to 9load(8) the boot sequence is:

  BIOS, MBR, PBS, 9load, kernel

The PBS program may be the culprit.  The last thing I see on a boot from
the HD is "PBS..." then the machine recycles to reboot.  From the floppy
the boot continues and is OK.

Question: How to verify and fix the PBS?

Later, Bob
--
bbourg-at-ccsi.com

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Dan Cross]

Hmm, you might need to use pbslba.  Just a guess.

	- Dan C.

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Fco.J.Ballesteros]

> Question: How to verify and fix the PBS?

I don't have a machine to do that, but verifying is easy:
try with a pbs from the worm to see if it works (actually, try
with versions backward in time, going back a month at a time).
If one works and the next does not, we could diff the source perhaps.

It would be hard for me these days (a story to long to tell), but I
can send whoever can test it a copy of the different pbss.

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[nofreakingspam]

"Fco.J.Ballesteros" wrote:
>
> > Question: How to verify and fix the PBS?
>
> I don't have a machine to do that, but verifying is easy:
> try with a pbs from the worm to see if it works (actually, try
> with versions backward in time, going back a month at a time).
> If one works and the next does not, we could diff the source perhaps.
>
> It would be hard for me these days (a story to long to tell), but I
> can send whoever can test it a copy of the different pbss.

Question: How to put [pbs | pbslba] on the HD of an already installed
system? Maybe, something like:

    Backup the files in 9fat;

    disk/format -b /386/[pbs|pbslba] -df /dev/sdC0!9fat

    Restore the files to 9fat.

Thanks, Bob
--
bbourg-at-ccsi.com

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[Fco.J.Ballesteros]

[-- Attachment #1: Type: text/plain, Size: 108 bytes --]

I always use something like

		disk/format -r 2 -d -b /386/pbslba \
			/dev/$disk/9fat /n/kfs/386/9load

[-- Attachment #2: Type: message/rfc822, Size: 2728 bytes --]

From: nofreakingspam@ccsi.com
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Plan 9 install doesn't put the right MBR on the disk
Date: Wed, 16 Jul 2003 08:26:23 -0500
Message-ID: <3F15527F.A09B94B3@ccsi.com>

"Fco.J.Ballesteros" wrote:
>
> > Question: How to verify and fix the PBS?
>
> I don't have a machine to do that, but verifying is easy:
> try with a pbs from the worm to see if it works (actually, try
> with versions backward in time, going back a month at a time).
> If one works and the next does not, we could diff the source perhaps.
>
> It would be hard for me these days (a story to long to tell), but I
> can send whoever can test it a copy of the different pbss.

Question: How to put [pbs | pbslba] on the HD of an already installed
system? Maybe, something like:

    Backup the files in 9fat;

    disk/format -b /386/[pbs|pbslba] -df /dev/sdC0!9fat

    Restore the files to 9fat.

Thanks, Bob
--
bbourg-at-ccsi.com

Re: [9fans] Plan 9 install doesn't put the right MBR on the disk

[andrey mirtchovski]

from http://plan9.bell-labs.com/magic/man2html/8/prep --

	Initialize the blank hard disk /dev/sdC0/data:

		disk/mbr -m /386/mbr /dev/sdC0/data
		disk/fdisk -baw /dev/sdC0/data
		disk/prep -bw -a^(9fat fs cache swap) /dev/sdC0/plan9
		disk/format -b /386/pbs -d -r 2 /dev/sdC0/9fat 9load 9pcdisk plan9.ini

I use the last line whenever my 9fat partitions get mangled by devfs :)