Linux boot process, module management and Loader (cont.)

1./etc/sysconfig/Directory Introduction:

1) Authconfig: This file is mainly in the specification of the user's identity authentication mechanism, including whether to use the native/etc/passwd,/etc/shadow password to record the use of the encryption algorithm, and whether to use external password server provided by the account verification, and/etc/ Shadow password records which encryption algorithm to use, and whether to use the external password server provided by the account Verification (NIS,LDAP) and so on. The system uses the MD5 encryption algorithm by default and does not use an external authentication mechanism

2) Clock: Set the time zone of the Linux host, basically, the time zone referenced in the Set project zone within the clock file is located in a relative path in the/usr/share/zoneinfo directory.

3) i18n: Set Language

4) Keyboard&mouse: Set the mouse and keyboard form

5) Network: Set to both start the networks, and set the hostname and network management (GATEWAY)

6) network-scripts/: Set network card

2. How to switch RunLevel:

1) Modify/etc/inittab, "ID: Number: Initdefault:" In the number [0-6]

2) temporarily change the runlevel of the system via init [0-6]

3.runlevel: Displays the current RunLevel

4./lib/modules/$ (UNAME-R)/kernel Introduction:

1) Arch: hardware platform related projects, such as CPU level and so on

2) Crypto: encryption technology supported by the core, such as MD5 or DES, etc.

3) Drivers: Some hardware drivers, such as display adapter, network card, PCI-related hardware, etc.

4) FS: FileSystem supported by the core

5) Net: network-related protocol data, as well as Firewall module (net/ipv4/betfilter/*), etc.

6) Sound: Various modules related to audio

5.depmod [-ane]:/lib/modules/$ (Uname-r)/MODULES.DEP records the dependencies of the modules supported in the core. The directive is to create this file, the parameters

1)-A: Without any parameters, Depmod will proactively analyze the current core module and re-write/lib/modules/$ (uname-r)/ MODULES.DEP, if you join the-a parameter, then Depmod will go to search than MODULES.DEP within the new module, if you really find a new module, will be updated

2)-N: Do not write as MODULES.DEP, but output the result to the screen

3)-E: Displays the name of the non-executable module that is currently loaded.

6.lsmod: Displays the modules that already exist in the core, including the following:

1) module name (modules)

2) module sizes (size)

3) Whether this module is used by other modules (used by)

7.modinfo [-ADLN] [Module_name|filename]: View module information, parameters,

1)-A: list author names only

2)-D: List only instructions for changing modules

3)-L: List authorizations only (license)

4)-N: Lists only the detailed path of the module

8.insmod [Fullpath/module_name] [params]: A full file name module is loaded by the user itself

9.modprobe: Actively search for MODULES.DEP content, will overcome the dependencies of the module before deciding which modules to load.

10.rmmod [-FW] module_name: Remove module, parameters,

1)-F: Force removal of the module, regardless of whether master is being used

2)-W: If the module is being used, Rmmod will wait for the module to be used before removing his

11.modprobe [-LCFR] module_name: module load related instructions, parameters,

1)-C: List all current system modules

2)-L: Lists all modules currently in/lib/modules/' Uname-r '/kernel full file name

3)-F: Force the module to load

4)-R: Similar to Rmmod, is to remove a module

Advantages of 12.grub (boot manager):

1) Recognize and support more file systems, and you can use Grub's main program to search the file system directly for the core file name

2) When the boot, you can edit and modify the boot settings project, NVC Bash Command mode

3) The configuration file can be dynamically searched without having to reinstall Grub after modifying the configuration file. That is, we only need to modify the/boot/grub/menu.lst (Grub configuration file) inside the settings, the next time the power-on is effective

13./boot/grub/menu.lst File Interpretation:

default=0: Default boot option, using first boot option

timeout=5: If the keyboard is 5 seconds, use the default boot option

splashimage= (hd0,0)/grub/splash.xpm.gz: Background image in the archive

Hiddenmenu: Whether to display the complete menu screen during the second reading (default hidden), if you want to display the menu to comment out the line

the contents of the first menu:

title CentOS (2.6.18-92.EL5)

Root (hd0,0)

kernel/vmlinuz-2.6.18-92.el5 ro root=label=/1 rhgb quiet

initrd/initrd-2.6.18-92.el5.img

14.INITRD: Provide the most important core modules needed during the boot process, so that the system can be completed smoothly. INITRD can be/lib/modules/... Within the boot process must be required in the module package into a file (file name is INITRD), and then at boot time through the host's INT 13 hardware function will be read out of the file decompression, and INITRD in memory will be emulated into the root directory, due to this virtual file system (Initial RAM Disk) mainly consists of disks and file system modules, so our core is finally able to know the actual disk, it is possible to carry out the actual root directory mount.

General requirements for INITRD are:

The root directory where the disk is SATA, USB ring SCSI and other connection interface;

The root directory is located in the file system for LVM, RAID and other special lattice interactive;

The root directory where the file system is a non-traditional Linux obituary file system;

Other modules that must be provided at core load time.

15.MKINITRD [-v] [--with= module name] INITRD file name core file name. Version: Production INITRD, parameters,

1)-V: Show the operation of MKINITRD

2)--with= module Name: module name is worth the name of the module, do not need to fill in. The current core version of the Ext3 file system module is the following file name:/lib/modules/$ (uname-r)/kernel/fs/ext3/ext3.ko then you should write:--with=ext3 (omit. Ko)

3) INITRD file name: The name of the INITRD file you want to create, try to make a meaningful and friendly

4) Core version: A core version, if the current core is $ (uname-r)

16.grub-inistall [--root-directory=dir] install_device, Parameters:

1)--root-directory=dir:dir is the actual directory, the use of Grub-install default will be all the grub files are copied to/boot/grub/*, if you want to assign to other directories and devices need to use this parameter

2) Install_device: Installed device code

This article is from "Tiger Brother's Blog" blog, please be sure to keep this source http://7613577.blog.51cto.com/7603577/1604144

Linux boot process, module management and Loader (cont.)