80
Chapter 4. Boot Loaders
4.4.2. File Names
When typing commands to GRUB involving a file, such as a menu list to use when allowing the
booting of multiple operating systems, it is necessary to include the file immediately after specifying
the device and partition. A sample file specification to an absolute filename is organized as follows:
( type of device
bios device number , partition number )/path/to/file
.
/-.
/
.
/
Most of the time, a user will specify files by the directory path on that partition, plus the filename.
It is also possible to specify files to GRUB that do not actually appear in the filesystem, such as a
chain loader that appears in the first few blocks of a partition. To specify these files, you must provide
a blocklist, which tells GRUB, block by block, where the file is located in the partition. Since a file
can be comprised of several different sets of blocks, there is a specific way to write blocklists. Each
file's section location is described by an offset number of blocks and then a number of blocks from
that offset point, and the sections are put together in a comma delimited order.
Consider the following blocklist:
0+50,100+25,200+1
This blocklist tells GRUB to use a file that starts at the first block on the partition and uses blocks 0
through 49, 99 through 124, and 199.
Knowing how to write blocklists is useful when using GRUB to load operating systems that use chain
loading, such as Microsoft Windows. It is possible to leave off the offset number of blocks if starting
at block 0. As an example, the chain loading file in the first partition of the first hard drive would have
the following name:
(hd0,0)+1
The following shows the
chainloader
command with a similar blocklist designation at the GRUB
command line after setting the correct device and partition as root:
chainloader +1
4.4.3. GRUB's Root Filesystem
Some users are confused by the use of the term "root filesystem" with GRUB. It is important to
remember that GRUB's root filesystem has nothing to do with the Linux root filesystem.
The GRUB root filesystem is the root partition for a particular device. GRUB uses this information to
mount the device and load files from it.
With Red Hat Linux, once GRUB has loaded its root partition, which equates to the
/boot
partition
and contains the Linux kernel, the
kernel
command can be executed with the location of the kernel
file as an option. Once the Linux kernel boots, it sets its own root filesystem. The original GRUB root
filesystem and its mounts are forgotten; they only existed to boot the kernel file.
Refer to the
root
and
kernel
commands in Section 4.6 for more information.
4.5. GRUB Interfaces
GRUB features three interfaces, which provide different levels of functionality. Each of these inter 
faces allows users to boot operating systems, and move between interfaces within the GRUB environ 
ment.






footer




 

 

 

 

 Home | About Us | Network | Services | Support | FAQ | Control Panel | Order Online | Sitemap | Contact

tomcat hosting

 

Our partners: PHP: Hypertext Preprocessor Best Web Hosting Java Web Hosting Inexpensive Web Hosting  Jsp Web Hosting

Cheapest Web Hosting Jsp Hosting Cheap Hosting

Visionwebhosting.net Business web hosting division of Web Design Plus. All rights reserved