Saturday, November 14, 2009

Notes on dual-booting Windows 7 and Linux

Dual-booting Windows 7 and Linux is mostly straightforward, but I ran into a few problems. The following notes describe my setup, mostly for my own benefit.

If you're looking for a comprehensive dual-boot tutorial, try apc or Loko.

My setup

I'm running Windows 7 and Fedora 11 Linux on a Gateway SX2800.

Partitioning

I use the Gnome Partition Editior (GParted). Windows 7 conveniently includes a partition software under Disk Management, but inconveniently it can't shrink a volume by a large amount.

My partitioning setup is a bit crazy. Because I bought my computer before Windows 7 was released, I used Windows 7 beta until I got the official upgrade DVD. One unpleasant surprise is you have to reinstall to get from the beta to Windows 7 Home Premium; you can't just upgrade. I had an empty E: partition, so I installed the offical release there, transferred my files with Windows Easy Transfer, and then spent an evening reinstalling all my software. I store most of my data on a FAT32 partition D:to avoid messing around with NTFS on Fedora.

You'll probably want something simpler than what I have, but my partition table is:

$fdisk /dev/sda
...
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1        1698    13631488   27  Unknown
/dev/sda2   *        1699       14445   102390277+   7  HPFS/NTFS
/dev/sda3           14446       27193   102398310    7  HPFS/NTFS
/dev/sda4           27194       77825   406701540    5  Extended
/dev/sda5           27194       28289     8803588+  82  Linux swap / Solaris
/dev/sda6           28290       70176   336457296    b  W95 FAT32
/dev/sda7           70177       77825    61440561   83  Linux
sda1 is a mysterious Gateway recovery partition, sda2 is C:, sda3 is E:, sda6 is D: for most of my data, and sda7 is the Linux partition.

/etc/fstab

/dev/sda7               /                       ext3    defaults        1 1
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/sda5  swap                    swap    defaults        0 0
/dev/sda6  /d   vfat auto,rw,user,sync,exec,dev,suid,uid=500,gid=500,umask=000 0 2

My GRUB config

default=1
timeout=5
splashimage=(hd0,2)/boot/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.30.9-96.fc11.i586)
 root (hd0,6)
 kernel /boot/vmlinuz-2.6.30.9-96.fc11.i586 ro root=/dev/sda7 rhgb quiet
 initrd /boot/initrd-2.6.30.9-96.fc11.i586.img
title Windows 7
 rootnoverify (hd0,1)
 chainloader +1
Note the off-by-one: (hd0,6) boots off sda7. For Windows, you need to specify the partition with the Windows boot loader; if I try to boot E: directly with (hd0,2), I get BOOTMGR IS MISSING.

Editing the GRUB config from Linux rescue boot

Invariably I end up unable to boot Linux from my disk. To fix this, I boot from my Linux CD and then fix the GRUB config. The following assumes sda7 is the Linux partition:
mount /mnt /dev/sda7
cd /mnt/boot/grub
vi menu.lst
grub-install --root-directory=/mnt /dev/sda

Editing the Windows boot loader configuration

If you have multiple versions of Windows, you'll need to configure the Windows boot loader through bcdedit: details.

Other random errors

My Fedora Core boot failed with an infinite loop of "init: ttyx respawning too fast, stopped". The solution was to change selinux=enforcing to selinux=permissive in /etc/selinux/config.

Conclusion

The above notes are mostly for my own benefit the next time I need to configure GRUB, but maybe they'll help someone else. Disclaimer: it's very easy to lose data or mess up your system so it won't boot. Back everything up and make sure you have Linux and Windows rescue disks. Don't blame me if things go wrong.

2 comments:

Anonymous said...

About the "BOOTMGR IS MISSING."

I also had that error.
It seems that Windows 7 is either using existing NTFS od FAT Partitions for its bootloader (probably to avoid breaking dual-boot installations with older windows versions - I dunno) OR it creates an extra mini Partition for its bootloader if it is the first System installed on the machine.

However, the Partition where the "main body" of your Windows 7 is installed is not the one you need to put into grub. You need to find out where W7 mislaid its bootloader.

Ronny said...

I also had the same error before.
Here's the solution:
edit the linux "/boot/grub/grub.conf" like this :

title Windows 7
root (hd0,0)
chainloader +1

because Win 7 boot from the first partition /dev/sda1 which is 100MB size.