Difference between pages "Talk:Read e-books with Linux" and "Boot process"
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| − | you | + | How Linux typically starts up on a PC |
| − | * | + | |
| − | * | + | = you switch on the computer = |
| − | * | + | BIOS is shown and the devices are check |
| − | * | + | |
| − | * | + | = the master boot record is executed = |
| − | * | + | |
| − | * | + | = the boot loader is executed = |
| − | * | + | The boot loader is typically grub, and there is an older and smaller called lilo. |
| − | * | + | |
| − | * | + | = the Linux kernel is executed = |
| − | * | + | |
| − | * | + | = the initrd is loaded/executed = |
| − | * | + | |
| − | * | + | = the init program is started = |
| − | * | + | The Linux kernel starts the init program. Nothing else. If the init process quits, the Linux kernel panics. Init is responsible for all further services and programs that are started. |
| − | * | + | |
| − | + | = the init script are executed = | |
| − | + | This can be SysV init scripts or upstart or systemd. These init scripts typically start services. Services are grouped into runlevels. Find out your current runlevel with the command | |
| − | + | runlevel | |
| − | + | Change your runlevel, in this case to 3, with the command | |
| − | + | init 3 | |
| − | + | ||
| − | + | E.g. in SUSE the runlevels are defines as | |
| − | + | * 0: reboot | |
| − | * | + | * 1: rescue system, single user |
| + | * 2: all services that run in (1) plus services needed for multi-user login | ||
| + | * 3: all services that run in (2) plus network services | ||
| + | * 4: undefined | ||
| + | * 5: all services that run in (3) plus graphical display | ||
| + | Some notable services are: | ||
| + | * alsasound | ||
| + | : Used for the alsa sound system | ||
| + | * cups | ||
| + | : Used for printing, it is the common Unix printing system | ||
| + | * dbus | ||
| + | : Used to call public functions in running programs. Should be abstracted to users. | ||
| + | * esound | ||
| + | : Used for enlightenment sound system | ||
| + | * ntp | ||
| + | : Network Time Protocol to keep your clock in sync with the real time via the network | ||
| + | * autofs boot.udev xdm | ||
| + | * cifs xfs | ||
| + | * cron ypbind | ||
| + | * powerd | ||
| + | * gpm network | ||
| + | * sshd | ||
| + | : Service that allows to [[control a computer via the network]] | ||
| + | |||
| + | = X Windowing system is started = | ||
| + | |||
| + | = login manager is started = | ||
| + | |||
| + | = user session incl. Desktop environment is started = | ||
| + | |||
| + | = See also = | ||
| + | * http://wiki.linuxquestions.org/wiki/Boot_process | ||
Revision as of 15:05, 11 January 2014
How Linux typically starts up on a PC
Contents
- 1 you switch on the computer
- 2 the master boot record is executed
- 3 the boot loader is executed
- 4 the Linux kernel is executed
- 5 the initrd is loaded/executed
- 6 the init program is started
- 7 the init script are executed
- 8 X Windowing system is started
- 9 login manager is started
- 10 user session incl. Desktop environment is started
- 11 See also
you switch on the computer
BIOS is shown and the devices are check
the master boot record is executed
the boot loader is executed
The boot loader is typically grub, and there is an older and smaller called lilo.
the Linux kernel is executed
the initrd is loaded/executed
the init program is started
The Linux kernel starts the init program. Nothing else. If the init process quits, the Linux kernel panics. Init is responsible for all further services and programs that are started.
the init script are executed
This can be SysV init scripts or upstart or systemd. These init scripts typically start services. Services are grouped into runlevels. Find out your current runlevel with the command
runlevel
Change your runlevel, in this case to 3, with the command
init 3
E.g. in SUSE the runlevels are defines as
- 0: reboot
- 1: rescue system, single user
- 2: all services that run in (1) plus services needed for multi-user login
- 3: all services that run in (2) plus network services
- 4: undefined
- 5: all services that run in (3) plus graphical display
Some notable services are:
- alsasound
- Used for the alsa sound system
- cups
- Used for printing, it is the common Unix printing system
- dbus
- Used to call public functions in running programs. Should be abstracted to users.
- esound
- Used for enlightenment sound system
- ntp
- Network Time Protocol to keep your clock in sync with the real time via the network
- autofs boot.udev xdm
- cifs xfs
- cron ypbind
- powerd
- gpm network
- sshd
- Service that allows to control a computer via the network
