TOPIC: GNU GRUB
Restoring GRUB for dual booting of Linux and Windows
11th April 2015Once you end up with Windows overwriting your master boot record (MBR), you have lost the ability to use GRUB. Therefore, it would be handy to get it back if you want to start up Linux again. Though the loss of GRUB from the MBR was a deliberate act of mine, I knew that I'd have to restore GRUB to get Linux working again. So, I have been addressing the situation with a Live DVD for the likes of Ubuntu or Linux Mint. Once one of those had loaded its copy of the distribution, issuing the following command in a terminal session gets things back again:
sudo grub-install --root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda
When there were error messages, I tried this one to see if I could get additional information:
sudo grub-install --root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda --recheck
Also, it is possible to mount a partition on the boot drive and use that in the command to restore GRUB. Here is the required combination:
sudo mount /dev/sda1 /mnt
sudo grub-install --root-directory=/mnt /dev/sda
Either of these will get GRUB working without a hitch, and they are far more snappy than downloading Boot-Repair and using that; I was doing that for a while until a feature on triple booting appeared in an issue of Linux User & Developer that reminded me of the more readily available option. Once, there was a need to manually add an entry for Windows 7 to the GRUB menu too and, with that instated, I was able to dual-boot Ubuntu and Windows using GRUB to select which one was to start for me. Since then, I have been able to dual boot Linux Mint and Windows 8.1, with GRUB finding the latter all by itself. Since your experiences too may show this variation, it's worth bearing in mind.
Sorting a kernel upgrade error in Linux Mint 13
30th November 2012Linux Mint 14 may be out now, but I'll be sticking with its predecessor for now. Being a user of GNOME Shell instead of Cinnamon or Mate, I'll wait for extensions to get updated for 3.6 before making a move away from 3.4 where the ones that I use happily work. Given that Linux Mint 13 is set to get support until 2017, it's not as if there is any rush either. Adding the back-ported packages repository to my list of software sources means that I will not miss out on the latest versions of MDM, Cinnamon and Mate anyway. With Ubuntu set to stick to GNOME 3.6 until after 13.04 is released, adding the GNOME 3 Team PPA will be needed if 3.8 arrives with interesting goodies; there are interesting noises that suggest the approach taken in Linux Mint 12 may be used to give more of a GNOME 2 desktop experience. Options abound and there are developments in the pipeline that I hope to explore too.
However, there is one issue that I have had to fix which stymies upgrades within the 3.2 kernel branch. A configuration file (/etc/grub.d/10_linux) points to /usr/share/grub/grub-mkconfig_lib instead of /usr/lib/grub/grub-mkconfig_lib so I have been amending it every time I needed to do a kernel update. However, it just reverts to the previous state, so I thought of another solution: creating a symbolic link in the incorrect location that points to the correct one so that updates complete without manual intervention every time. The command that does the needful is below:
sudo ln -s /usr/lib/grub/grub-mkconfig_lib /usr/share/grub/grub-mkconfig_lib
Of course, figuring out what causes the reversion would be good too, but the symbolic link fix works so well that there's little point in exploring it further. Of course, if anyone can add how you'd do that, I'd welcome this advice too. New knowledge is always good.
On Upgrading to Linux Mint 11
31st May 2011For a Linux distribution that focuses on user-friendliness, it does surprise me that Linux Mint offers no seamless upgrade path. In fact, the underlying philosophy is that upgrading an operating system is a risky business. However, I have been doing in-situ upgrades with both Ubuntu and Fedora for a few years without any real calamities. A mishap with a hard drive that resulted in lost data in the days when I mainly was a Windows user places this into sharp relief. These days, I am far more careful but thought nothing of sticking a Fedora DVD into a drive to move my Fedora machine from 14 to 15 recently. Apart from a few rough edges and the need to get used to GNOME 3 together with making a better fit for me, there was no problem to report. The same sort of outcome used to apply to those online Ubuntu upgrades that I was accustomed to doing.
The recommended approach for Linux Mint is to back up your package lists and your data before the upgrade. Doing the former is a boon because it automates adding the extras that a standard CD or DVD installation doesn't do. While I did do a little backing up of data, it wasn't total because I know how to identify my drives and take my time over things. Apache settings and the contents of MySQL databases were my main concern because of where these are stored.
When I was ready to do so, I popped a DVD in the drive and carried out a fresh installation into the partition where my operating system files are kept. Being a Live DVD, I was able to set up any drive and partition mappings by referring to Mint's Disk Utility. One thing that didn't go so well was the GRUB installation, and it was due to the choice that I made on one of the installation screens. Despite doing an installation of version 10 just over a month ago, I had overlooked an intricacy of the task and placed GRUB on the operating system files partition rather than at the top level of the disk where it is located. Instead of trying to address this manually, I took the easier and more time-consuming step of repeating the installation like I did the last time. If there was a graphical tool for addressing GRUB problems, I might have gone for that instead, but am left wondering at why there isn't one included at all. Maybe it's something that the people behind GRUB should consider creating, unless there is one out there already about which I know nothing.
With the booting problem sorted, I tried logging in, only to find a problem with my desktop that made the system next to unusable. It was back to the DVD and I moved many of the configuration files and folders (the ones with names beginning with a ".") from my home directory in the belief that there might have been an incompatibility. That action gained me a fully usable desktop environment, but I now think that the cause of my problem may have been different to what I initially suspected. Later I discovered that ownership of files in my home area elsewhere wasn't associated with my user ID though there was no change to it during the installation. As it happened, a few minutes with the chown command were enough to sort out the permissions issue.
The restoration of the extra software that I had added beyond what standardly gets installed was took its share of time but the use of a previously prepared list made things so much easier. That it didn't work smoothly because some packages couldn't be found the first time around, so another one was needed. Nevertheless, that is nothing compared to the effort needed to do the same thing by issuing an installation command at a time. Once the usual distribution software updates were in place, all that was left was to update VirtualBox to the latest version, install a Citrix client and add a PHP plugin to NetBeans. Then, next to everything was in place for me.
Next, Apache settings were restored as were the databases that I used for offline web development. That nearly was all that was needed to get offline websites working but for the need to add an alias for localhost.localdomain. That required installation of the Network Settings tool so that I could add the alias in its Hosts tab. With that out of the way, the system had been settled in and was ready for real work.
Given the glitches I encountered, I can understand the Linux Mint team's caution regarding a more automated upgrade process. Even so, I still wonder if the more manual alternative that they have pursued brings its own problems in the form of those that I met. The fact that the whole process took a few hours in comparison to the single hour taken by the in-situ upgrades that I mentioned earlier is another consideration that makes you wonder if it is all worth it every six months or so. Saying that, there is something to letting a user decide when to upgrade rather than luring one along to a new version, a point that is more than pertinent in light of the recent changes made to Ubuntu and Fedora. Whichever approach you care to choose, there are arguments in favour as well as counterarguments too.
Manually adding an entry for Windows 7 to an Ubuntu GRUB2 menu
21st November 2010A recent endeavour of mine has been to set up a dual-booting arrangement on my Toshiba Equium laptop, with Ubuntu 10.10 and Windows 7 side by side on there. However, unlike the same attempt with my Asus Eee PC where Windows XP coexists with Ubuntu, there was no menu entry on the GRUB (I understand that Ubuntu has had version 2 of this since 9.04 though the internal version is of the form 1.9x; you can issue grub-install -v at the command line to find out what version you have on your system) menu afterwards. Thankfully, I eventually figured out how to do this and the process is shared here in a more coherent order than the one in which I discovered all the steps.
The first step is to edit /etc/grub.d/40_custom (using sudo) and add the following lines to the bottom of the file:
menuentry 'Windows 7' {
set root='(hd0,msdos2)'
chainloader +1
}
Since the location of the Windows installation can differ widely, I need to explain the "set root" line because (hd0,msdos2) refers to /dev/sda2 on my machine. More generally, hd0 (or /dev/sda elsewhere) refers to the first hard disk installed in any PC, with hd1 (or /dev/sdb elsewhere) being the second and so on. While I was expecting to see entries like (hd0,6) in /boot/grub/grub.cfg, what I saw were ones like (hd0,msdos6) instead with the number in the text after the comma being the partition identifier; 1 is the first (sda1), 2 (sda2) is the second and so on. The next line (staring with chainloader) tells GRUB to load the first sector of the Windows drive so that it can boot. After all that decoding, my final remark on what's above is a simple one: the text "Windows 7" is what will appear in the GRUB menu, so you can change this as you see fit.
After saving 40_custom, the next step is to issue the following command to update grub.cfg:
sudo update-grub2
Once that has done its business, then you can look into /boot/grub/grub.cfg to check that the text added into 40_custom has found its way in there. That is important because this is the file read by GRUB2 when it builds the menu that appears at start-up time. A system reboot will prove conclusively that the new entry has been added successfully. Then, there's the matter of selectively to see if Windows loads properly like it did for me, once I chose the correct disk partition for the menu entry, that is!
Solving an upgrade hitch en route to Ubuntu 10.04
4th May 2010After waiting until after a weekend in the Isle of Man, I got to upgrade my main home PC to Ubuntu 10.04. Before the weekend away, I had been updating a 10.04 installation on an old spare PC and that worked fine, so the prospects were good for a similar changeover on the main box. That may have been so, but breaking a computer hardly is the perfect complement to a getaway.
To keep the level of disruption to a minimum, I opted for an in-situ upgrade. The download was left to complete in its own good time, and I returned to attend to installation messages asking me if I wished to retain old logs files for the likes of Apache. When the system asked for reboot at the end of the sequence of package downloading, installation and removal, I was ready to leave it do the needful.
However, I met with a hitch when the machine restarted: it couldn't find the root drive. Live CD's were pressed into service to shed light on what had happened. First up was an old disc for 9.10 before one for 10.04 Beta 1 was used. That identified a difference between the two that was to prove to be the cause of what I was seeing. 10.04 uses /dev/hd*# (/dev/hda1 is an example) nomenclature for everything, including software RAID arrays ("fakeraid"). 9.10 used the /dev/mapper/sil_**************# convention for two of my drives, and I get the impression that the names differ according to the chipset that is used.
During the upgrade process, the one thing that was missed was the changeover from /dev/mapper/sil_**************# to /dev/hd*# in the appropriate places in /boot/grub/menu.lst; look for the lines starting with the word kernel. When I did what the operating system forgot, I was greeted by a screen telling of the progress of checks on one of the system's disks. While that process took a while, a login screen followed, and I had my desktop much as before. The only other thing that I had to do was run gconf-editor from the terminal to send the title bar buttons to the right, where I am accustomed to having them. Since then, I have been working away as before.
Some may decry the lack of change (ImageMagick and UFRaw could do with working together much faster, though) but I'm not complaining; the rough of 9.10 drilled that into me. Nevertheless, I am left wondering how many are getting tripped up by what I encountered, even if it means that Palimpsest (what Ubuntu calls Disk Utility) looks much tidier than it did. Could the same thing be affecting /etc/fstab too? The reason that I don't know the answer to that question is that I changed all hard disk drive references to UUID a while ago, but it's another place to look if the GRUB change isn't fixing things for you. If my memory isn't failing me, I seem to remember seeing /dev/mapper/sil_**************# drive names in there too.