Re: [SLE] Dual-booting...or trying, heh

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To: suse-linux-e@suse.com
Date: Thu, 10 Feb 2005 20:37:40 +0000

On Thursday 10 February 2005 7:50 am, Darryl Gregorash wrote:
> John B wrote:
> >Heya gang,
> >
> > I just installed W98 on a second hdd for a few games *only*. The way I
> > did it, was open case, unhook Linux hdd and made second hdd hdd0,
> > installed M$, rehooked everything back to normal.

<snip>

> I do believe that Win98, being just M$-DOS 6 with a GUI, does not know
> about modern things such as booting off something other than the master
> on the primary IDE -- hda aka. hd0 To make things worse, this being DOS,
> there can only be one primary partition on the boot device. (Someone
> please correct me if I am wrong, but I believe this limitation does no
> longer exist in Win2K or XP, but both still must boot from the
> primary/master.)

Correction coming up. Your version is the simple version of the story. The
original PC design provides for up to 4 primary partitions on a hard drive,
as you state later. In the DOS world, only 1 primary partition can be active
on a single hard drive. A FAT32 drive is type 0x0c, but when hidden it is
type 0x1c. Similarly, NTFS is 0x07 and 0x17.

To boot a DOS operating system [msdos 1.0 through MSXP] requires that the
active primary partition on the first hard drive is booted. BIOSs which boot
from other drives do this by presenting the other selected drive as the first
drive.

To boot different DOS os's on different primary partitions requires that the
partition types are changed, to hide all but the required partition. fdisk
will do this for DOS, but you need to know what you will boot next, before
you shut down [or boot up, do fdisk and reboot]. GRUB and LILO manage the
changing of partition types during boot.

Booting MS98 from the second hard drive is 'unsupported' but possible with
some limitations. The best is to make space for a tiny primary partition,
with a boot sector, the hidden files and config.sys and edit whatever sets
the windows directory [msdos.sys? so long ago, I have forgotten] to point to
the windows directory of the installation on the second hard drive.

Alternatively, I believe it may be possible to point GRUB to the boot sector
on the second hard drive and boot that, even if the pc bios will not boot it,
or if the bios is still set to boot from the first drive. Note that if the
installation was done with this drive as C:, the registry may be confused,
unless the installation partition is the first FAT partition on first and
second drives, in which case it may be accepted as C:, even though it is on
the second drive.

>
> Now we have a bit of a problem, because I believe LILO also cannot boot
> off anything except the master on the primary IDE -- but at least we can
> have more than one primary partition, 4 of them in fact (or 3 plus an
> extended partition, in case you need more). You can put a primary
> partition on the first drive and hide it whenever you boot DOS (also you
> have to mark the DOS partition "active"), or you can leave things as you
> have them and swap the hard drives in the BIOS (using the boot manager,
> of course).

True, LILO and GRUB are subject to exactly the same rules as DOS. As above,
LILO and GRUB can be configured to manage hiding and unhiding.

>
> LILO can do all this for you, but GRUB is much easier to configure and
> maintain. LILO at times seems to me to be cryptic and unintuitive; GRUB
> is straightforward and intuitive. It's up to you, but I do suggest you
> install and use GRUB instead of LILO. Either way, your fstab is
> irrelevant for now, and probably will need modification only if you want
> to access the Win98 stuff from Linux.

LILO is prone to being broken if any of the files it uses are rewritten,
because it only knows the files by hardware address on the disk [every time
you change one of the key files, you must run a LILO config utility]. GRUB
knows files by name, and can tolerate them being rewritten.

Vince

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• Previous message: Bruce Marshall: "Re: [SLE] Dual-booting...or trying, heh"
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