14_01~~14_04

14_01

Linux system startup process

Post (power on Self Test)-->bios (Boot Sequence)-->mbr (bootloader,446 (MBR reads only one, no longer reads second))-->kernel (typically compressed)-- (ROOTFS)/sbin/init (/etc/inittab)-->-->-->

The service started differently:

Operating level: 0-6

0:halt (OFF)

1:single user mode, directly into the administrator identity

2:multi user mode, no NFS

3: Multi User mode (text multi-user)

4:reserved (temporarily unused, reserved mode)

5: Multi User mode (graphical multi-user, graphic mode)

6:reboot ()

Verbose start-Up process: (Windows Bootloder does not recognize other systems, so if you first install Linux and then install Windows,windows bootloader will be the Linux bootloader cover out, Installing a dual system requires installing Windows first)

！！ WIN8 will lock the MBR, so after installing the WIN8, the hard disk will not be able to install other systems

Linux bootloader (MBR)

Lilo:linux LOader (cannot boot 1024 cylinders after the partition kernel, does not support the disk after 8G, suitable for embedded)

Grub:grand Unified Bootloader

Stage1:mbr

Stage1_5:

stage2:/boot/grub/

Grub.conf

Default=0 # Sets the number of the default start title, starting with 0

Timeout=s # waits for the user to select the timeout length, in seconds

Splashimage= (hd0,0)/grub/splash.xpm.gz # Grub Background image

Hiddemenu: # Hide Menu

Title Red Hat enterprice Linux Server (2.6.18-308.el5) #内核标题, or operating system name, string, can be freely modified

Root (hd0,0) #内核文件所在的设备: For grub, all types of hard drives are HD, in the Format (hd#,n): hd#, #表示第几个磁盘: The last N indicates the partition of the corresponding disk;

kernel/vmlinxu-2.6.18-308.el5 ro root=/dev/vo10/root rhgb quiet #内核文件路径, and parameters passed to the kernel

initrd/initrd- 2.6.18-308.el5.img RAMDisk file path (generated by the last step of installing the SYSTEM)!!!! Version number to be consistent

,,,,

,,,,

,,,,

Kernel design style:

Core: Dynamic loading of peripheral kernel modules

Kernel:/lib/modules/"kernel version number named directory"/

Kernel itself name: vmlinux-x.x.x

/lib/modules/2.26.32/

Redhat5:ramdisk-->initrd

Redhat6:ramfs-->initramfs

Redhat,suse

Single core: simple design, Linux (thread in Linux is called, lightweight process--LWP. )

Core: KO (Kernel object)

So ()

Microkernel: Complex design, windows,solaris (threads)

Chroot: The directory in which to replace the root. : Chroot/psth/to/temproot [COMMAND ... ]

Chroot/test/virrot/bin/bash

Ldd/psth/to/binary_file: Displays the shared library since the binaries

The root is self-referencing.

10:0:wait:/ETC/RC.D/RC 0

rc0.d/

k*

Stop

s*

Start

/ETC/RC.D/INIT.D,/ETC/INIT.D

Service class Script:

Start

SysV:/ETC/RC.D/INIT.D

Start|stop|restart|status

Reload|configtest

Chkconfig (! Although Chkconfig and description are commented out, Chkconfig will still analyze the two lines. When we use the Chkconfig command, any script that has these lines can be automatically created for the connection)

#chkconfig: Runlevels SS (Start priority) KK (Close priority)

Runlevels: '-' indicates that there is no level, default is the connection at the beginning of s*;

If the ellipsis level is specified, the default is 2,345 levels or the current level;

When the Chkconfig command creates a connection for this script in the RC#.D directory, runlevels indicates that the connection is created by default for the beginning of the s*, and that all other levels are created by default for the connection beginning with k*;

The start priority at the back of S is the number represented by SS, and the number after K is closed in order of precedence for KK;

#description: Description of the simple function of this script; \, continue.

@@@ The first service is turned off, and the service that is turned on is turned off first because the service that is first opened may be dependent on the service behind it.

Chkconfig

--list NULL to see the start-up settings for all independent daemons, Independent daemons!

--list Service Name View specific services

Chkconfig--add service_name Creating a link file for/RC.D

Chkconfig--del Service Name Delete a link file under/RC.D

Chkconfig--level runlevels service name {On|off}

MYSERVICE.SH: Determine if a service is turned on by lock file

#!/bin/bash

#

#chkconfig: 2345 77 22

#description: Test Service

#

Lockfile=/var/lock/subsys/myservice

Status () {

If [-e $LOCKFILE]; Then

echo "Running ..."

Else

echo "stoped."

Fi

}

Usage () {

echo "' basename $ ' {start|stop|restart|status}"

}

Case $ in

Start

echo "Starting ..."

Touch $LOCKFILE

;;

Stop

echo "Stoping ..."

Rm-f $LOCKFILE &>/dev/null

;;

Restart

echo "Restart ..."

;;

Status

Status

;;

*)

Usage

;;

Esac

/etc/rc.d/rc.local: The system finally starts a service, exactly said, should execute a script;

S99loacl the last startup script when the system starts.

So some inconvenient to define as a service, or we can not easily write it as a script command, we may be written here!!!!!!

/etc/inittab's Mission:

1, set the default operating level;

2, run the system initialization script;

3. Run the script in the directory corresponding to the specified level;

4, set the operation of Ctrl+alt+del combination key;

5, define the UPS power supply in the power failure/recovery operation performed;

6, start the virtual terminal (2,345 level);

7, start the graphics terminal (5 level);

Daemon Type:

Independent Daemon Process

XINITD: Super Daemon (requires associated runlevel). The Super daemon is the agent of the Transient daemon (multiple Super Daemons)

Transient daemon: No need to correlate to runlevel (multiple transient daemons)

Core:/boot/vmlinuz-version

Kernel module (KO):/lib/modules/version/

Kernel design:

Single Core

Modular design

Micro-core

Loading module:

Insmod

Modprobe

www.kernel.org

kernel-2.6.17------2 (major version number). 6 (minor version number). 17 (fixed number)

How user space accesses and monitors the kernel:

/proc,/sys

Pseudo file System

/proc/sys: Many of the files in this directory are readable and writable

/sys/: Some files can be read and written

Method for setting kernel parameter values: (temporary)

echo VALUE >/proc/sys/to/somefile

Sysctl-w Kernel.hostname

Permanent (not effective immediately):/etc/sysctl.conf

Command immediately in effect: #sysctl-P-------notifies the kernel to reread sysctl.conf

SYSCTL-A: Show all kernel parameters and their values

Kernel Module Management:

Lsmod: Viewing the kernel modules used

Modprobe mod_mame; loading a module

Modprobe-r mod_mame; uninstalling a software module

Modinfo: View information about a module

insmod/path/to/module_file; loading module

Rmmod Mod_name;

Depmod /path/to/module_dir;

Post-->bios (Boot Sequence)--BootLoader (MBR)-->kernel (INITRD,INITRAMFS)-->init (/etc/inittab)

/etc/inittab:

Setting the default Run level

System Initialization (/ETC/RC.D/RC.SYSINIT)

Run a service script at the specified level

/etc/rc.d/init.d/

/etc/rc.d/rc#.d

Rc0.d--rc6.d

k*

s*

00-99: Run order

Start a virtual terminal

Start the graphics terminal

/etc/rc.d/rc.sysinit:

Detect and re-mount the root file system in read-write mode;

Set host name;

Detect and mount other file systems in the/etc/fstab;

Start swap partition;

Initialize the drive of the peripheral hardware device;

RHRL6:

Upstart-->init

/etc/inittab

/etc/init/*.conf

Kernel initialization:

16_01

Compile kernel:

1. Configuration

Make Menuconfig

Make Gconfig

Make Kconfig

Make Oldconfig

Make Config

Save As. config

2.

Make

Make Modules_install

Make install

Module Installation Location:/lib/modules/kernel_version/

How to implement partial compilation:

1. Compile only the relevant code under a subdirectory:

Make dir/

Make arch/

Make drivers/net/

2. Compile only some modules

Make m=drivers/net/

14_01~~14_04