[CentOS] installing C7 on a laptop with Win7, dual boot

Mon Mar 2 12:19:09 UTC 2015
Fred Smith <fredex at fcshome.stoneham.ma.us>

On Mon, Mar 02, 2015 at 04:24:47AM +0000, Richard wrote:
> 
> 
> ------------ Original Message ------------
> > Date: Sunday, March 01, 2015 21:50:34 -0500
> > From: Fred Smith <fredex at fcshome.stoneham.ma.us>
> > To: centos at centos.org
> > Subject: Re: [CentOS] installing C7 on a laptop with Win7, dual
> boot
> >
> > On Mon, Mar 02, 2015 at 02:04:24AM +0000, Richard wrote:
> >> 
> >> 
> >> ------------ Original Message ------------
> >> > Date: Sunday, March 01, 2015 20:06:26 -0500
> >> > From: Fred Smith <fredex at fcshome.stoneham.ma.us>
> >> > To: centos at centos.org
> >> > Subject: [CentOS] installing C7 on a laptop with Win7, dual boot
> >> > 
> >> > Hi all!
> >> > 
> >> > I've just installed C7 on my netbook that already contained Win7
> >> > (and also Fedora 19, which the C7 is intended to replace). The
> >> > Fedora installer had found the windows installation and it
> >> > appeared in the grub menu, and was bootable and worked fine.
> >> > 
> >> > The C7 installer did not put the windows installation into the
> >> > grub menu.
> >> > 
> >> > with some googling I found a page at
> >> > https://priteshugrankar.wordpress.com/2014/09/12/dual-booting-c
> >> > ent os-7-and-windows-7/ that gives a simple recipe for fixing
> >> > this problem. basically:
> >> > 
> >> > cp /boot/grub2/grub.cfg orig.grub.cfg
> >> > grub2-mkconfig -o /boot/grub2/grub.cfg
> >> > 
> >> > with (on his system) the second command above producing this
> >> > output:
> >> > 
> >> > 	[root at localhost ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
> >> > 	Generating grub configuration file ...
> >> > 	Found linux image: /boot/vmlinuz-3.16.2-1.el7.elrepo.x86_64
> >> > 	Found initrd image:
> >> > 	/boot/initramfs-3.16.2-1.el7.elrepo.x86_64.img Found linux
> >> > 	image: /boot/vmlinuz-3.10.0-123.el7.x86_64 Found initrd image:
> >> > 	/boot/initramfs-3.10.0-123.el7.x86_64.img Found linux image:
> >> > 	/boot/vmlinuz-3.10.0-123.6.3.el7.x86_64 Found initrd image:
> >> > 	/boot/initramfs-3.10.0-123.6.3.el7.x86_64.img Found linux
> >> > 	image:
> >> > /boot/vmlinuz-0-rescue-327fe33f3b364802871211321a2790b7 	Found
> >> > initrd image:
> >> > /boot/initramfs-0-rescue-327fe33f3b364802871211321a2790b7.img
> >> > 	Found Windows 7 (loader) on /dev/sda1
> >> > 	Found Windows 7 (loader) on /dev/sda2
> >> > 	done
> >> > 
> >> > Unfortunately, when I did it, I got this:
> >> > 
> >> > Generating grub configuration file ...
> >> > Found linux image: /boot/vmlinuz-3.10.0-123.el7.x86_64
> >> > Found initrd image: /boot/initramfs-3.10.0-123.el7.x86_64.img
> >> > Found linux image: /boot/vmlinuz-3.10.0-123.20.1.el7.x86_64
> >> > Found initrd image:
> >> > /boot/initramfs-3.10.0-123.20.1.el7.x86_64.img Found linux
> >> > image:
> >> > /boot/vmlinuz-0-rescue-c875112952114f6284f69abaa4f9a2f7 Found
> >> > initrd image:
> >> > /boot/initramfs-0-rescue-c875112952114f6284f69abaa4f9a2f7.img
> >> > done
> >> > 
> >> > No mention of the windows installation.
> >> > 
> >> > It's not that I use the win7 installation much, but I do want to
> >> > be able to do so when one of those rare occasions pops up.
> >> > 
> >> > Thanks in advance!
> >> > 
> >> > Fred
> >> 
> >> I too encountered this issue putting centos7 on a win7 machine.
> >> The solution is to:
> >> 
> >> edit:   
> >> 
> >>     /etc/grub.d/40_custom
> >> 
> >> putting in:
> >> 
> >>     menuentry 'name' {
> >> 
> >>     insmod ntfs
> >> 
> >>     set root=(hd0,2)
> >> 
> >>     chainloader +1
> >> 
> >>     }
> >> 
> >> note: "name" can be anything you want (within reason), and is the
> >> name that will show in the boot menu. 
> > 
> > So, I did this. I'm assuming that 'name' should be bare, with no
> > quotes? well, I tried it both ways, makes no difference. The
> > grub-mkconfig does not emit any lines about having found windows.
> > its output looks the  same as what I showed in the original mail,
> > above.
> > 
> > there are 3 windows partitions, two of which appeared in grub
> > previously. Here's the entry I made:
> > 
> > menuentry Win-7 {
> > insmod ntfs
> > set root=(hd0,1)
> > chainloader +1
> > }
> > 
> > 
> >> 
> >> the values here:
> >> 
> >>     root=(hd0,2)
> >> 
> >> will vary based on your disk setup. if you still have your fc19
> >> grub/grub2 (whichever it used) configuration file you should be
> >> able to confirm the values from that.
> > 
> > I can still access the files (I made an image of the disk), but
> > grub2 configurations are not human-readable, so I can't figure it
> > out from that. however, if I look at the drive image with fdisk,
> > it shows partition 2 as being bootable, so I used (hd0,1). maybe I
> > s hould try (hd0,2) as an alternative...
> > 
> >> 
> >> when done, then:
> >> 
> >>   grub2-mkconfig -o <output file>
> >> 
> >> personally, i didn't set the -o to the production grub.cfg file as
> >> my preference is to make backups and check things before
> >> potentially trashing a file like that, but do as you wish. when
> >> you're comfortable with the generated file move it to the
> >> production location and reboot.
> >> 
> >> 
> >>     - Richard
> >> 
> 
> I believe you need quotes around the "name" value, but will admit I
> haven't tried without.
> 
> Correct, the grub2-mkconfig command doesn't emit lines about
> windows, but it puts the above lines into the resulting
> (grub2/grub.cfg) file - towards the bottom. [You could hand-edit
> these lines into that file if you want, but having them in the
> 40_custom file means that they will be included when the grub.cfg
> file is recreated after a linux kernal update.]
> 
> When you boot the machine you should see the (windows) "name" entry
> at the bottom of the list of kernel options. Select it and the
> machine should boot into windows.

Yes, I do see that, and it does work. Thanks for the help!
> 
> Windows does have a couple of partitions -- the main/production
> bootable one as well as a rescue one. I believe that (hd0,2) is the
> default location/naming for the production/bootable one.

I'll see if I can add another stanza for the windows recovery partition,
for just in case it becomes necessary.

thanks again!

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
  "For him who is able to keep you from falling and to present you before his 
 glorious presence without fault and with great joy--to the only God our Savior
 be glory, majesty, power and authority, through Jesus Christ our Lord, before
                     all ages, now and forevermore! Amen."
----------------------------- Jude 1:24,25 (niv) -----------------------------