Re: Please help with following situation

[Steve Cohen]

Okay, got this working.

1) backed up all needed stuff
2) ran gparted and totally remade disk as follows (after choosing option 
to start all partitions on cylinder boundaries:

$ sudo fdisk /dev/sda
[sudo] password for scohen:

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): p

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0003f2d6

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         131     1052226   83  Linux
/dev/sda2             132         164      265072+   6  FAT16
/dev/sda3             165        9729    76822831    5  Extended
/dev/sda5             166         295     1044225   82  Linux swap / Solaris
/dev/sda6             296        9729    75778573+  83  Linux

3) Then installed reinstalled Ubuntu
with /dev/sda1 = /boot
     /dev/sda2 = /DOS
     /dev/sda5 = swap
     /dev/sda6 = /

4) restored all backups
5) added /etc/grub.d/11_msdos as follows
#!/bin/sh -e
echo "Adding MS-DOS"
cat << EOF
menuentry "MS-DOS" {
set root=(hd0,2)
makeactive
chainloader +1
}
EOF

And all is well.  Under DOS the /dev/sda2 partition did not even require 
formatting.

I think the key thing may have been the cylinder boundaries.  Or maybe 
it was that the DOS was in /dev/sda2 instead of /dev/sda3 this time.

Live and learn.


On 11/22/2010 08:19 AM, Steve Cohen wrote:
> I am glad to hear that this is possible.
>
> Perhaps the following fdisk output might shed light on the situation:
>
> $ sudo fdisk /dev/sda
>
> WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
> switch off the mode (command 'c') and change display units to
> sectors (command 'u').
>
> Command (m for help): p
>
> Disk /dev/sda: 80.0 GB, 80026361856 bytes
> 255 heads, 63 sectors/track, 9729 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x000b6a5d
>
> Device Boot Start End Blocks Id System
> /dev/sda1 * 1 947 7605248 83 Linux
> Partition 1 does not end on cylinder boundary.
> /dev/sda2 973 9730 70337537 5 Extended
> /dev/sda3 964 982 143640 e W95 FAT16 (LBA)
> Partition 3 does not end on cylinder boundary.
> /dev/sda5 973 1459 3905536 82 Linux swap / Solaris
> /dev/sda6 1460 9730 66430976 83 Linux
>
> Partition table entries are not in disk order
>
> Command (m for help): c
> DOS Compatibility flag is not set
>
> Command (m for help): p
>
> Disk /dev/sda: 80.0 GB, 80026361856 bytes
> 255 heads, 63 sectors/track, 9729 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disk identifier: 0x000b6a5d
>
> Device Boot Start End Blocks Id System
> /dev/sda1 * 1 947 7605248 83 Linux
> /dev/sda2 973 9730 70337537 5 Extended
> /dev/sda3 964 982 143640 e W95 FAT16 (LBA)
> /dev/sda5 973 1459 3905536 82 Linux swap / Solaris
> /dev/sda6 1460 9730 66430976 83 Linux
>
> Partition table entries are not in disk order
>
> If not for the "not end on cylinder boundary" and "not in disk order"
> situations, do you think the the general layout of partitions should
> work? I could possibly reinstall the whole system. There is not that
> much there. If so, what should I do differently?
>
>
>
> On Sun, 21 Nov 2010 01:44:19 -0500 Felix Miata wrote
> > On 2010/11/21 14:21 (GMT+0800) Goh Lip composed:
> >
> >
> > Just struck me, normally windows, prior to Windows XP, always insist on
> > being set to the first primary partition
> >
> >
> > That's a myth. Most of my many DOS and Windows primaries are either a
> > 2nd or a 3rd.
> >
> > What is necessary is:
> >
> >
> > 1: it thinks its C: is _any_ (unhidden) first disk primary
> >
> >
> > 2: no other "first disk" primaries of any type it understands are
> > unhidden
> >
> >
> > 3: at most one primary on any of the first 2 HDs is set active/startable
> >
> >
> > 4: if no boot manager (e.g. Grub) is installed, its primary must be
> > active/startable (via standard/generic MBR code)
> > --
> > "The wise are known for their understanding, and pleasant
> > words are persuasive." Proverbs 16:21 (New Living Translation)
> >
> > Team OS/2 ** Reg. Linux User #211409
> >
> >
> > Felix Miata *** http://fm.no-ip.com/