Linux Booting Procedure gEnabling the ARM Learning in INDIAHow Linux boot?Enabling the ARM Learning in INDIASystem startupEnabling the ARM Learning in INDIA Booting is a bootstrapping process that startsoperating systems when the user turns on acomputer system A boot sequence is the set of operations theHow computer startup?q pcomputer performs when it is switched onthat load an operating systemEnabling the ARM Learning in INDIA1 !ern on" #P$ %ump to address of B&'S ()x****)+, B&'S runs P'S! (Power-'n Self !est+. *ind bootale de/ices0 Loads and execute boot sector form 1B2Booting sequence0 Loads and execute boot sector form 1B23 Load 'SEnabling the ARM Learning in INDIA B&'S refers to the software code run by a computer when firstpowered on !he primary function of B&'S is code program embedded on a chipthat recognises and controls /arious de/ices that ma4e up thecomputerB&'S (Basic &nput5'utputSystem+B&'S on boardB&'S on screenEnabling the ARM Learning in INDIA 'S is booted from a hard dis46 where the 1aster Boot2ecord (1B2+ contains the primary boot loader !he 1B2 is a 01"-byte sector6 located in the first sector onthe dis4 (sector 1 of cylinder )6 head )+ After the 1B2 is loaded into 2A1 the B&'S yields control1B2 (1aster Boot 2ecord+ After the 1B2 is loaded into 2A16 the B&'S yields controlto itEnabling the ARM Learning in INDIA1B2 (1aster Boot 2ecord+Enabling the ARM Learning in INDIA !he first ..3 bytes are the primary boot loader6 whichcontains both executable code and error message text !he next sixty-four bytes are the partition table6 whichcontains a record for each of four partitions !he 1B2 ends with two bytes that are defined as the1B2 (1aster Boot 2ecord+!he 1B2 ends with two bytes that are defined as themagic number ()xAA00+ !he magic number ser/es as a/alidation chec4 of the 1B2Enabling the ARM Learning in INDIA !o see the contents of 1B26 use this command7 8 dd if95de/5hda of9mbrbin bs901" count91 8 od -xa mbrbin::!he dd command6 which needs to be run from root6 reads the first 01"bytes from 5de/5hda (the first &ntegrated ;ri/e $ *lexible command line interface *ile system access Support multiple executable formatGRUB: GRand Unified Bootloader Support multiple executable format Support dis4less system ;ownload 'S from networ4 ; 7 (*ilesystem standard+ de! - ;e/ice files etc - #onfiguration files specific to the machine s"el - Fhen a home directory is created it is initiali@ed withfiles from this directory s#sconfig - *iles that configure the linux system for de/icesEnabling the ARM Learning in INDIA !ar - #ontains files that change for mail6 news6 printers log files6man pages6 temp files file lib - *iles that change while the system is running normally local - Gariable data for programs installed in 5usr5local loc" - Loc4 files $sed by a program to indicate it is using a particular de/iceor file*SS!>; 7 (*ilesystem standard+ log - Log files from programs such as login and syslog which logs all logins andlogouts run - *iles that contain information about the system that is /alid until thesystem is next booted spool - ;irectories for mail6 printer spools6 news and other spooled wor4 tmp - !emporary files that are large or need to exist for longer than theyshould in 5tmp catman - A cache for man pages that are formatted on demandEnabling the ARM Learning in INDIA mnt - 1ount points for temporary mounts bythe system administrator tmp - !emporary files Programs running afterb h ld 5 5*SS!>; 7 (*ilesystem standard+bootup should use 5/ar5tmpEnabling the ARM Learning in INDIA