Date: Tue, 24 Oct 1995 11:30:48 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: lmcerpr@lmc.ericsson.se (Eric Primeau) Cc: questions@FreeBSD.org, lmcerpr@lmc.ericsson.se Subject: Re: Missing operating system Message-ID: <199510240200.LAA03886@genesis.atrad.adelaide.edu.au> In-Reply-To: <9510231608.AA00904@egg.lmc.ericsson.se> from "Eric Primeau" at Oct 23, 95 12:08:38 pm
next in thread | previous in thread | raw e-mail | index | archive | help
Eric Primeau stands accused of saying:
> PLEASE HELP ME!!
> I am facing the famous "Missing operating system" problem.
Your disk geometry is wrong.
> Then I bought a 1Gb IDE disk and split it into two partitions: 400Mb intended for FreeBSD
> and 600Mb for DOS (defined as primary DOS). (I put the FBSD partition lower because of a note
> I read somewhere about a possible problem with this.) NOTE: DOS sees this 600Mb partition
> as drive D:.
This was a wise move.
> Because my IDE CDROM isnt supported by FreeBSD 2.0.5,
> I copied the DISTS files unto the D: disk (600Mb DOS partition).
No problem.
> NOTE: I set the geometry of my drive according to the specification written on it
> e.g. 2112/16/63. The root partition is set to be bootable ("A" appears in fdisk).
Is this the same geometry that your BIOS is set to for this disk? In
particular, the 16/63 values are crucial. Did you install something like
Ontrack's Disk Mangler in order to work with the oversized IDE disk? This
may well be your problem, as it uses a nonstandard disk layout.
> I perform a "Minimal" installation from Media="DOS partition" and it seems to succeed
> with no error messages. NOTE: I choose the "Boot Manager" option.
>
> When all is finished and I reboot, the boot manager prompts me for:
> F1 DOS F5 disk 2
>
> If I choose F1, DOS boots OK.
> If I choose F5, I get "Missing operating system" and the system hangs.
This sounds like there is a problem with the layout of the second disk.
> -------------------------------
> Variations:
> At one point I got desperate. I tried installing with the "Standard MBR" instead of
> with the Boot Manager. After the installation I rebooted and got the message
> (something like) "NO ROM SYSTEM HALTED" with system hang.
NO ROM BASIC... This means that the disk is not considered bootable.
I strongly suspect that you are using Disk Mangler or an equivalent.
> Now there are a few things I dont understand.
>
> 1) Where does the boot manager reside? On disk 0 (e.g. my 170Mb DOS C: drive)? Or on disk 1 (1Gb) ?
The boot manager lives in the MBR of the disk. It's odd that despite you
installing on the _second_ disk, the boot manager shows up. FreeBSD is quite
paranoid about only installing the bootmanager on the disk being installed
to. The fact that this occurs suggests to me that Disk Mangler (or an
equivalent) has replaced the MBR bootcode on the first disk with code that
reads the MBR bootcode from the _second_ disk.
> 2) Why cant the boot manager boot from the 1Gb drive?
> Must I make a small FreeBSD partition on disk C:?
The 'missing operating system' message actually comes from the BIOS. It's
very strange that you get it _after_ seeing the bootmanager; normally if
the bootmanager can't boot the nominated partition, it comes back with F?
as a prompt.
> 3) What's the problem with the geometry? Initially, fdisk states "528/64/63"
> and I have to change it to "2112/16/63" (when you add it up it's the same thing, no?).
> What does the geometry have to do with boot ?
The number of sectors per track is _crucial_ in locating the beginning
of the first partition on the disk, because it starts at the beginning of
the second track. If the geometry that FreeBSD used for the install is
different from the geomtry that the BIOS sees, the boot manager will not
be able to find the beginning of the FreeBSD partition, and thus won't be
able to boot.
> 4) Two of my colleagues have FreeBSD but they have dedicated disks.
> In my case I dont want to use the whole 1Gb drive just for FreeBSD.
> Is it possible to get DOS and FreeBSD to co-exist on my disk?
Yes, it should be. I would be inclined to blow away the disk and any stupid
Disk Mangler code on it (boot from a floppy and run fdisk), and give yourself
a 450M DOS 'slice', and then use the rest for FreeBSD. As long as the
FreeBSD root partition is under the 500M mark, everything will be fine, and
you won't need any funny tools for DOS to be able to access the disk.
I strongly suspect that the hidden driver is your problem.
> Eric PRIMEAU lmcerpr@lmc.ericsson.se
--
]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[
]] Genesis Software genesis@atrad.adelaide.edu.au [[
]] High-speed data acquisition and [[
]] realtime instrument control (ph/fax) +61-8-267-3039 [[
]] My car has "demand start" -Terry Lambert UNIX: live FreeBSD or die! [[
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199510240200.LAA03886>