1. 5 – Boot process
Marian Marinov Borislav Varadinov
CEO of 1H Ltd. System Administrator
mm@1h.com bobi [ at ] itp.bg

2. ● Local boot process
– HDD
– CD
– USB
● Boot loaders
● Remote booting
– With local drives
– Without local drives

3. ➢ Hardware initialization
➢ Find all storage controllers
➢ Initialize all storage controllers
➢ BIOS storage search
➢ Depending on the BIOS boot priority list
➢ Hard Disks
➢ CD
➢ USB
➢ Floppy
➢ Network

4. ● Identify bootable device
● Search for boot loader
● Copy the loader into memory

5. ➢ Search the first 1024 bytes
➢ If partition table is found, search for the first
PRIMARY partition marked as BOOT
➢ Search the first 1024 bytes of the partition
➢ Load the boot loader into memory
➢ Set the Instruction Pointer to the beginning of
the boot loader binary

6. Boot loaders
➢ LILO
➢ GRUB/GRUB2
➢ SYS/ISOLINUX
➢ uBoot
➢ PXElinux

7. Boot loaders
➢ LILO
➢ Direct block offset to the kernel
➢ The loader and its configuration is written
directly in the MBR
➢ Support for serial console
➢ Kernel parameters prompt
/etc/lilo.conf
image = /boot/bzImage-3.8.2-terion
root = /dev/sdb2
label = Terion-3.8.2
read-only

8. Boot loaders
➢ GRUB/GRUB2
➢ Only the base loader data is written in the
MBR, everything else is read from the device
➢ Dynamic configuration
➢ Shell like command prompt
➢ Support for serial console
➢ Support network loading of binaries

9. Boot loaders
➢ GRUB
/boot/grub/menu.lst
title CentOS (2.6.32-279.14.1.el6.x86_64)
root (hd0,1)
kernel /vmlinuz-2.6.32-279.14.1.el6.x86_64 ro root=/dev/sda4
crashkernel=auto SYSFONT=latarcyrheb-sun16 LANG=en_US.UTF-8
KEYTABLE=us
initrd /initramfs-2.6.32-279.14.1.el6.x86_64.img

10. Boot loaders
➢ GRUB2
menuentry 'Fedora (3.7.6-201.fc18.i686)' --class fedora --class gnu-linux --class gnu
--class os {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod ext2
set root='(hd0,msdos5)'
search --no-floppy --fs-uuid --set=root f098d5f7-abf7-4161-966b-
b265c6179abe
echo 'Loading Fedora (3.7.6-201.fc18.i686)'
linux /vmlinuz-3.7.6-201.fc18.i686 root=UUID=c567e7ef-eb7e-4ced-8c21-
64d1075eb72e ro rd.md=0 rd.lvm=0 rd.dm=0 KEYTABLE=us quiet
SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=en_US.UTF-8
echo 'Loading initial ramdisk ...'
initrd /initramfs-3.7.6-201.fc18.i686.img
}

11. Boot loaders
➢ ISO/SYSLINUX
➢ Mainly used for live/install CD/USB
➢ Static configuration
➢ No command prompt

12. Boot loaders
➢ uBoot
➢ Developed entirely for embedded devices
➢ EVERYTHING embedded runs this
➢ Configuration similar to SYSLINUX

13. Network Boot
➢ Optional (boot)ROM
➢ Currently implemented directly in the BIOS
on almost all new hardware
➢ With local storage
➢ Without local storage

14. Network Boot
BIOS
DHCP Server Acquire IP address
Load Network boot loader Optional ROM
TFTP Server
Boot loader
Load OS Kernel
Kernel

15. Boot process
http://academy.telerik.com/student-courses/software-technologies/os-windows-linux/

16. Beer time

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