Книга: Fedora™ Unleashed, 2008 edition
System Services and Runlevels
System Services and Runlevels
After finishing with rc.sysinit script during the bootloading process, the init command uses the Linux system initialization table found in /etc/inittab to boot Fedora to a specific system state. The state of the system is commonly referred to as its runlevel.
Several different ways of starting and stopping system services exist, and Fedora uses a method derived from System V Unix. The System V (pronounced "System Five") method uses runlevels and different combinations of services to define different states of operation. Runlevels determine which of the many available system services are started, as well as in which order they start. A special runlevel is used to stop the system, and a special runlevel is used for system maintenance. As you will see, there are other runlevels for special purposes.
NOTE
The System V method makes extensive use of symbolic links, which are ways to reference a file in another location and make it appear as if it were in two or more places at once. The benefit is that you need to edit only one file to change them all. In addition, any reorganization to be done means that only links need to be changed, not the files themselves.
You use runlevels to manage the system services running on your computer. All these special files and scripts are set up during your installation of Fedora Linux, and they receive their initial values based on your choices during the installation — as described in Chapter 1, "Installing Fedora," You can change and control them manually, as you learn later in this chapter, using tools of varying sophistication.
Оглавление книги
- Beginning the Boot Loading Process
- Loading the Linux Kernel
- System Services and Runlevels
- Runlevel Definitions
- Booting into the Default Runlevel
- Booting to a Nondefault Runlevel with GRUB
- Understanding init Scripts and the Final Stage of Initialization
- Controlling Services at Boot with Administrative Tools
- Running Services Through xinetd
- Changing Runlevels
- Phone Services
- Running Services at Bootup
- Understanding init Scripts and the Final Stage of Initialization
- Controlling Services at Boot with Administrative Tools
- Changing Runlevels
- 10.3 RTOS Services
- Разработка приложений баз данных InterBase на Borland Delphi
- Open Source Insight and Discussion
- Introduction to Microprocessors and Microcontrollers
- Chapter 6. Traversing of tables and chains
- Chapter 8. Saving and restoring large rule-sets
- Chapter 11. Iptables targets and jumps