GNU GRUB (short for GNU GRand Unified Bootloader) is a boot loader package from the GNU Project. GRUB is the reference implementation of the Free Software Foundation.

Nothing can beat having a great Linux distro installed on a super-fast hard drive, with all your favourite apps configured just how you like them and all your files. In this article we are going to review boot process in Linux Operating System.We see how Operating system passes through different stage of booting states.

The r. EFInd Boot Manager: Methods of Booting Linuxby Roderick W. Smith, rodsmith@rodsbooks. Originally written: 3/1. Web page update. 8/1. EFInd 0. 1. 1. 0. This Web page is provided free of charge and with no annoying outside ads; however, I did take time to prepare it, and Web hosting does cost money.

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Donate another value. This page is part of the documentation for the r. EFInd boot manager. If a Web search has brought you here, you may want to start at the main page. Windows and Mac OS X both provide relatively simple EFI boot loader programs. Launch them, and they'll boot their respective OSes.

This makes r. EFInd's job easy; it just locates the boot loader program files and runs them. Under Linux, by contrast, things can get complicated. As detailed on my Managing EFI Boot Loaders for Linux page, several different EFI boot loaders for Linux exist, and all of them require configuration. If you're lucky, your distribution will have set up a Linux boot loader in a sensible way, in which case r.

EFInd should detect it and it will work as easily as a Windows or Mac OS X boot loader. If you're not lucky, though, you may need to configure it further. Naturally, r. EFInd supports traditional Linux boot loaders. It works even better with the Linux EFI stub loader, so I provide instructions on starting with it. For those interested in manual configuration, I also provide detailed instructions on how the EFI stub support works and how to configure it. I consider ELILO, GRUB Legacy, GRUB 2, and SYSLINUX to be traditional Linux boot loaders. These programs all exist independent of the Linux kernel, but they can load a kernel and hand off control to it.

All four programs have their own configuration files that reside in the same directory as the boot loader itself (or optionally elsewhere, in the case of GRUB 2). Ordinarily, r. EFInd will detect these traditional boot loaders and provide main menu entries for them. If the boot loader exists in a directory with a name that matches a Linux distribution's icon filename, you'll automatically get a distribution- specific icon to refer to the boot loader. If you prefer, you can disable automatic scanning and create an entry in refind. Configuring the Boot Manager page.

This method is harder to set up but can be preferable if you want to customize your options. The EFI stub loader is basic and reliable, but it requires some setup to use it on some computers. It also requires that you run a kernel with the same bit width as your EFI.

In most cases, this means running a 6. EFI- based computers are so rare. I describe three methods of using the EFI stub loader: an easiest method for those with compatible partition and filesystem layouts, a quick test configuration for those without such a layout, and a long- term setup for those without the ideal setup.

In most cases, the first (easiest) method works fine, thanks to r. EFInd's filesystem drivers and r. EFInd features intended to help launch a kernel with minimal user configuration.

This method requires that your /boot directory, whether it's on a separate partition or is a regular directory in your root (/) filesystem, be readable by the EFI. At the moment, all EFI implementations can read FAT and Macs can read HFS+. By using drivers, you can make any EFI read HFS+, ISO- 9. Reiser. FS, ext. 2fs, ext. Btrfs, or other filesystems. Thus, if you use any of these filesystems on a regular partition (not an LVM or RAID configuration) that holds your kernels in /boot, you qualify for this easy method. The default partition layouts used by Ubuntu, Fedora, and many other distributions qualify, because they use one of these filesystems (usually ext.

You must also have a 3. How To Install Adobe Media Encoder Cs6 Manual here. Linux kernel with EFI stub support, of course. If you installed r. EFInd 0. 6. 0 or later with its refind- install (formerly install.

Linux installation, chances are everything's set up; you should be able to reboot and see your Linux kernels as boot options. If you installed manually, from OS X, or from an emergency system, though, you may need to do a couple of things manually. Copy the relevant driver file for your filesystem and architecture to. You may need to create this subdirectory, too. Create a refind. The mkrlconf script that comes with r.

EFInd. should do this job, or you can do it manually as described later. Starting with version 0. EFInd can. create minimal boot options from /etc/fstab, if /boot.

Version 0. 9. 0 also adds the ability. Discoverable. Partitions Spec, if your disk uses the appropriate type codes. A. refind. If they work, your job is done, although you might want to apply some of the tweaks described in the maintenance- free setup section. If you have problems, you may need to adjust the refind. This procedure assumes that you have access to a 3. Linux kernel with EFI stub support compiled into it. The procedure for a quick test is: Copy your kernel file (vmlinuz- *) and matching initial RAM.

EFI on your ESP. Your distribution's directory there should. For instance, typing cp. Note that the filename forms vary from one. Be sure that you match up the correct files by version number. Copy the /boot/refind. If this file doesn't exist, create it by.

EFInd. This step may not be strictly necessary if /boot. Reboot. You should now see a new entry for launching the Linux kernel. Try the option. If it works, great. If not, you may. need to adjust your refind. See the detailed configuration section for a description of.

If the kernel begins to boot but complains that it. RAM disk file, and check the root=. This can be a hassle. A better way is to configure you system so that the EFI, and therefore r.

EFInd, can read your Linux /boot directory, where most Linux distributions place their kernels. You do this by installing the appropriate EFI filesystem driver for the /boot (or root, /) filesystem. If your /boot directory happens to be on an XFS or JFS partition that the EFI can't read, or it's tucked away in an LVM or RAID configuration that the EFI can't read, you won't be able to use the easiest solution. Fortunately, this problem can be overcome with relatively little fuss. Several variant procedures are possible, but I begin by describing one that will almost always work, although it's got some important caveats (described at the end).

You should perform the following steps as root, or precede each of these commands with sudo: Begin with your ESP mounted at /boot/efi, which is the most. If it's not mounted there, type mount /dev/sda. Check the size of the ESP by typing df - h. The ESP must be large enough to hold several Linux.

RAM disk files—1. Mi. B at a bare minimum, and. Mi. B. Check your /boot directory to be sure it contains no links or. Unix/Linux- style permissions or ownership. If. it does, don't proceed, or at least research these files further to. Type cp - r /boot/* /boot/efi. You'll see an. error message about being unable to copy /boot/efi into.

Ignore this. Type umount /boot/efi. Edit /etc/fstab and change the mount point for. If the ESP isn't present in.

Type mount - a to re- mount everything. Check that your normal /boot files. EFI directory, which. EFI. If something seems to be. If it doesn't already exist, create a file called. If this file doesn't.

EFInd 0. 5. 1 and. Check your refind. EFI/refind) to be sure that the. If it's not. uncomment that line. Optionally, type cp. EFI/refind/icons/os. Therefore, you ended up with two copies of your kernels and other /boot directory contents, with one copy hiding the other when you mounted the ESP at /boot.

Once you've booted successfully and are sure all is working well, you can recover some disk space by unmounting /boot and deleting the contents of the underlying /boot directory on your root (/) filesystem. Be sure that the /boot partition is unmounted before you do this, though!