Lecture #3 Boot Loaders and Booting

Agenda

1. Review
   • Partitions
   • File Systems
   • File Types
2. Overview of System Architecture
3. Create a bootdisk using mkbootdisk
4. Exercise: Use the dd command to:
   • save a copy of the master boot record
   • echo your name to /dev/sda and attempt to reboot the system.
   • restore a copy of the master boot record
5. Demonstration of a system booting.
6. Create a GRUB boot disk
7. Boot a unix system into single user (maintenance) mode.
8. Exercise: Install CentOS:
   • Create a custom virtual machine with an IDE hard disk of 6 GB and 512 MB RAM called Computer2
   • Choose the following disk partitioning scheme:
     • a primary boot partition ~100MB
     • a primary root partition ~3GB
     • a primary swap partition ~1GB
     • one logical partition for /home ~1GB
   • Make custom changes to the software installed by deselecting Office Applications and Graphics. (This will save time with the install.)

Assignment

1. Finish reading Chapter 2 pages 32 - 42 on booting.
   Be able to answer the following questions:
   1. How is the Master Boot Record (MBR) different from a partition boot record?
   2. What is meant by a stage 2 boot loader?
   3. What is similar about the LILO and GRUB boot loaders? What is different?
2. Do Lab 2
   Here is a HowTo with screenshots for this lab done on a Fedora System.

Boot Loaders and Booting

1. Boot Sequence
   1. BIOS
   2. MBR Bootloader
   3. Boot Partition bootloader
   4. Secondary bootloader (optional)
   5. Kernel load
   6. Mount root filesystem
   7. Turn control over to an init program
2. Boot Loaders
   1. MS-DOS boot loader - no configuration file - noninteractive
   2. Syslinux - syslinux.cfg
   3. LILO - /etc/lilo.conf
          Requires the running of the lilo command to create a map file
   4. GRUB - /boot/grub/grub.conf
          Capable of reading many UNIX file systems including ext2
3. The dd Command
   • Can copy data within or outside of file system structures
   • Syntax: dd if=input-file of=output-file bs=blocksize count=#-of-blocks
   • Example: dd if=/dev/hda of=mbr bs=512 count=1
     Copies the master boot block to the file mbr

Relevant Commands and Files