Booting Technical Details
http://www.linux-boot.net/Boot.Sequence/
Stage 0 = in the BIOS
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Execute a JMP at 0xFFFFFFF0 ( 1st instruction after power on )
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Power-On-Self-Test
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Detect hardware
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Load Interrupt Vector table ( 0x0 )
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Find Master Boot Sector ( 1st 512Bytes and sector ends with 0xaa55 )
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Copy Master Boot Sector ( track 0 Sector 0 ) into RAM at 0x7C00
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Execute ( int 0x19 ) the MBR ( aka 1st Stage Loader ) moved to 0x9000
Stage 1 BootLoader ( aka Master Boot Sector )
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the BootLoader is arch/i386/boot/bootsect.S
Displays: Loading…..
o setup() is loaded at 0x00090200
o zImage is loaded at 0x00010000 bootsect.S -Ttext 0x1000
o bzImage is loaded at 0x00100000 bbootsect.S -Ttext 0x100000 -D'BIG_KERNEL'
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Print L than load 2nd stage
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Print I than execute the 2nd stage
Stage 1.5 FS
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Grub will load its filesystem boot info
Stage 2 Main Boot Process
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Print L than load 2nd stage
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Read the /boot/map file
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Print O after the map file was loaded
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Grub and Lilo will show its kernel options to boot
Displays: Uncompressing vmlinuz…..
Stage 3 Kernel - Hardware Detect and Scan
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Jump/Execute setup() ( arch/i386/boot/setup.S or bsetup.S )
o Scan the PCI bus for peripherals: KB, mouse, svga, disks
o setup interrupts vectors
o Load the device Drivers ( modules )
o switch from real-mode to protected mode
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— or — is this where: "uncompressing linux" displays
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Jump/Execute startup_32() ( arch/i386/kernel/head.S ) ( Start PID=0 )
Stage 4 Root FileSystem
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Jump/Execute start_kernel() ( start PID=1 )
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Load the optional ramdisk ( execute /linuxrc ) or is it before pid=0
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run init ( /etc/inittab ) ( PID = 1 )
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run rc.sysinit
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run rcx.d init scripts
BgLug.ca Linux Boot Process ( LinuxBootProcess.pdf ) ( local copy )
KevinBoone.com Understanding the Linux Boot Process
ExecPC.com Writing Your Own BootLoader
ExecPC.com i386 Boot Protocol
NonDot.org Boot Process
LinuxDevCenter.com
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How Your Computer Boots, start_kernel() , Loading…, Uncompressing…
TLDP.org Kernel Image - lots of details - start_kernel()
Moses.ukLinux.net Kernel Image
wustl.edu Similar to Hacking Grub
fifi.org Hacking Grub ( same as LinuxSelfHelp )
LinuxSelfHelp.com Hacking Grub ( same as FiFi.org )
uruk.org Grub Technical Info ( Boot Limits/Issues )
Temple.edu
rhce2b.com annoying popups
documented on: 2005.01.14
