But there are times when that trust old application needs to have a bit of a tweaking and when that time comes, you’re going to need to know exactly what to tweak and what to do post-tweak. In this Ghacks article I am going to introduce you to some of the fundamentals of the Grub2 bootloader.

What the bootloader does

In a nutshell, the bootloader instructs the kernel how it is supposed to boot. Without the bootloader the kernel wouldn’t get it’s initialization instructions (which kernel is default, any switches that are passed at startup, etc). Of course this is a vast over-simplification of what the boot loader does, but for the newer user, it’s explanation enough.

Handy Grub switches

There are plenty of Grub command line switches that you can use upon boot. But first you have to get to the Grub command prompt. To do this hit the “e” key when you see the kernel listing at boot followed by <Ctrl>x. This will land you in the Grub command prompt, at which point you can run any of the following:

• grub> CTRL + X: Boots any arguments you enter into the commandline.
• grub> halt: Shuts down the computer
• grub> reboot: Reboot the computer
• grub> help: :ists all available commands (which is quite a few)
• grub> help a: Lists all available commands that start with the letter a
• grub> ls: Lists all available partitions on your disk(s)
• grub>ls (hdx,x): Lists all files on that partition
• grub>cat (hdx,x)file: Outputs the contents of “file”

Configuring Grub

I am going to demonstrate how to make a change to Grub and then make that change take effect. There are a few files that might seem like the one you want to edit. The real file you should edit is /etc/default/grub. When you open this file take notice of the following entry:
GRUB_DEFAULT=0

That line instructs which kernel is the default to boot. You may find any number of entries in your Grub configuration file. For each kernel version you will find a standard entry and a recovery mode entry. The are numbered 0,1,2,3,4, etc. Look through your Grub configuration file for the kernel line you want to be the default entry. Remember, numbering starts at 0 not 1. So the third entry will actually be 2. Change that GRUB_DEFAULT= line to reflect the entry you want to serve as the default, save and close the file, and then run the following command update Grub:

sudo update-grub

Now when you reboot your machine, it will default to the kernel you have chosen as default. This is always helpful when you are experimenting with kernels or you get an upgraded kernel that breaks a feature.

Final thoughts

The boot loader for your machine is crucial. Take good care of this tool and it will do the same for you. But do use caution when undertaking any task that involves the boot loader, else you render your machine unbootable. Of course Grub is much more than what you have been shown here. We’ll get into more about this powerful boot loader later.

Windows boot manager Boot-US is a universal boot manager that can boot many operating systems properly including all versions of Microsoft Windows from Windows 95 to Windows Server 2008, MS-Dos, Linux, Free BSD, VMWare and several exotic operating systems like Oberon, Novel-DOS or QNX Realtime Plattform.

The boot manager itself can be installed in the MBR (Master Boot Record), the primary partition or on disk. The latter being an excellent way of testing the boot manager before installing it on the hard drive.

Other interesting functions of the Windows boot manager are (Windows because it is a Windows application):

• Support for hard disks up to 2048 GB (2 TB)
• Allows booting beyond the 8 GB limit
• Partitions can be created, deleted, activated and hid
• Password protection for boot manager and configuration program
• Command-line and GUI version
• True hiding of partitions

During program start the Windows boot manager is displaying the discovered partitions and the existing operating systems. It is important to make sure that the information that are displayed are correct before installing the boot manager. The user should also consider making backups of the list of partitions and boot sectors to be able to revert back if the installation of the boot manager goes wrong in any way. Those are just precautionary measures.

After that the user should install the boot manager to a floppy disk first if one is installed on the computer system. Most modern computers come without a floppy disk drive. Those users can check out the Copy and run Floppy Boot Disks from USB to add the boot manager to an USB device and boot the computer system from that device to be able to test the boot manager. Make sure to select Do not change partitions IDs in step four of the boot manager creation.

When the test is going through without errors the boot manager can be installed on the primary partition or Master Boot Record. The software developers recommend to install the boot manager in the primary partition if possible.

The Windows Boot Manager Boot-US was tested on a Windows XP Service Pack 3 test system without difficulties.

I first tried editing the boot.ini but did not find an entry for Vista in there. After searching the internet for about half an hour I discovered many forum entries about the problem that I faced and finally a link to a program called Windows Vista Boot Pro, a freeware which displays the boot information in Windows XP and the option to edit the entries.

The first tab of the Vista Boot Pro displays the boot information that are stored in BCD Store. My previous assumption proved correct because there was no drive assigned to my Vista operating system which was strange. I switched to the Manage Os Entries and created a new entry for Vista with the correct drive letter. I also deleted the old non-working one.

After that I rebooted the machine and was able to load Vista without problems. I hope that everyone who encounters Vista boot problems will find this tool as well. As Borat would put it: It is nice..