Basic components of Linux:
We can break down the Linux into multiple modules. This modular nature allows developers to work more efficiently and independently. Developers can reuse these modules for achieving different results. There are six categories associated with Linux. These are : network, init, shells & utilities, kernel, daemons and X window.
Network
Linux systems are most commonly arranged in client server networks. For users some computers act as server while other computers act as client or workstations. Clients can even require X Window data which means we can setup the terminals on Linux clients that access their GUI data from Linux server.
Init
Generally one Linux program starts another Linux program, e.g. you log in with the help of another Linux terminal program, known as mingetty. But some other program has to start the terminal program itself. When we start our system, the kernel loads and starts init program. Then this init program mounts our drives and starts the terminal programs.
Shells and utilities
We talk to the kernel using user mode programs. These programs consist of shells and utilities. These programs do not communicate directly with our hardware rather it is the job of kernel. We have three basic types of user mode programs:
1. Shell – these programs work as command interpreters. Most common Linux shell is bash
(Bourne Again Shell).
2. Login – These programs associate user ID with user’s shell & other personalized settings.
3. Utilities – These are very small commands which are used within a shell.
Kernel
It is the inner most part of any O.S. The kernel communicates with the system hardware through dedicated device drivers. If after installing new device, it is not detected, then we can add the driver module to our kernel. The other part of kernel, manage the stored data in disk cache as well as the Linux file system. The protected mode memory is used to hold the loaded kernel at the time of system start up.
Daemons
The daemons are such programs which run in background. These can be started as and when required. Many daemons can run simultaneously and can be in ready state to serve our web pages, print our documents, or they can start our network and so on.
X Window
The graphical window managers, like KDE, GNOME and other graphical applications, are built on foundation of X Window system.
Structure of LINUX operating system:
1. The kernel: Like UNIX it is the heart of Linux O.S. Kernel mixed form of multiple programs, which communicate with hardware. There is only one kernel in any O.S. When the system boot, it gets loaded in the main memory. It manages the system resources.
2. The shell: It provides the interaction between user and kernel it understands the function done by user so the kernel can get done the functions through the hardware, what a user is expecting
3. Linux Application & Utilities: The Linux contents many graphical and character based programs on this layer.
Advantages of Red Hat Linux:
Linux advantages are its price and its reliability. Its initial price is free. But when we talk about its affordability, we think of its total cost, which includes the capability of using cheaper hardware & compatible free add on applications.
So far as the reliability is concerned, Linux is more reliable than most desktop operating systems. We don’t have to reboot the system every time we change any setting.
The other advantage of Linux is the help, which is always available on the internet. In Linux news group or mailing list there is always one or other person willing to help you solve your problems.
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