One minute Master Linux system grub.conf configuration Core Knowledge

The boot loader, boot loader, is a small program that the computer runs before it loads the operating system kernel. With this applet, you can initialize the hardware device, set up a map of the memory space, and load the system's hardware and software environment into a suitable state to prepare for the final call to the operating system kernel. Typically, the boot loader relies on hardware implementations, with 2 common boot loaders for earlier Linux systems, Grub and Lilo, which are now mainstream (like the boot. ini bootstrap file under Windows).

The bootloader reads the configuration information of the grub.conf file and then launches different operating systems based on the corresponding configuration information, and the administrator can view the configuration information for the grub.conf from three paths (essentially one), as follows:

[Email protected] boot]# cat/etc/grub.conf

#<== can also read/boot/grub/menu.lst (soft links) or/boot/grub/grub.conf (real files).

... Omit multiple lines of comment information, in fact, the comments here have been explained quite clearly, only 90% of beginners can not see here ...

Default=0

#<== how the system is loaded by default, 0 indicates the first name in the Load menu, and the default add-on can be adjusted when multiple systems are available.

Timeout=5

#<== indicates how many seconds to start loading the default system, giving the administrator the time to select ahead.

Splashimage= (hd0,0)/grub/splash.xpm.gz

#<== The background icon that is displayed at startup, and (hd0,0) represents the/boot partition.

Hiddenmenu

When the #<== system starts, it hides the boot menu information and starts the system by default, unless the user presses the key to intervene.

password [–md5|–encrypted] STRING

#<== when editing the Grub menu, you need to enter password authentication, one of the Linux Foundation optimizations, not by default.

Title CentOS 6 (2.6.32-696.el6.x86_64)

#<== the project name of the system to be started, and can be modified as needed.

Root (hd0,0)

#<== boot the kernel file and the partition where the kernel needs the driver files, (hd0,0) represents the/boot partition.

#<== where hd0 represents the first disk of the computer, (hd0,0), 0 of the comma after the first partition, that is, (hd0,0) represents the first partition of the first disk, that is, the/DEV/SDA1 (the partition is usually the first independently separated/boot partition, The corresponding device name is SDA1).

kernel/vmlinuz-2.6.32-696.el6.x86_64 ro root=uuid=491eabe5-e6c0-4457-9bdb-b37cc6751308 rd_NO_LUKS rd_NO_ Lvm. UTF-8 rd_no_md sysfont=latarcyrheb-sun16 crashkernel=auto keyboardtype=pc keytable=us rd_NO_DM rhgb quiet

The #<== line indicates that the kernel is loaded, which reads the kernel files on the boot partition and a bunch of optional kernel parameters.

#<==/vmlinuz-2.6.32-696.el6.x86_64 is the kernel file. Root=uuid= The following string represents the root corresponding device information (/DEV/SDA3), the other introduction of the role of small, can be ignored.

initrd/initramfs-2.6.32-696.el6.x86_64.img #<== The location of the driver files required to boot the kernel, which exists in the boot area.

Hint: This grub.conf knowledge in fact in Enterprise Linux operation is not very large, the purpose of explaining grub is to hope that the reader can understand the Linux system of the entire start-up process to do the groundwork, RHCE Certification course will have to repair grub.conf exam questions, in fact, no big use, because in the IT website operation, very few Online processing problems, the problem is also a direct switch service, and then slowly study the repair or reload can be.

Reprint Address: http://blog.51cto.com/oldboy/2093484

One minute Master Linux system grub.conf configuration Core Knowledge