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Linux Overview


A. What is Linux
Linux is a UNIX-Based Operating System, and it is well-known that UNIX operating system was designed to be scalable, reliable, modular, secure and portable with network extensibility. Thus, Linux is considered as a multi-user, multi-tasking, network-enabled operating system accessible from anywhere on the network. Multiple users can access a Linux computer remotely, each running their own individual desktop instance, all at the same time. The Linux/Unix X-Windows network enabled multi-user windowing system allows full remote access. The Linux/Unix OS was designed to support remote and secure multi-user access using SSH. This gives all Linux/Unix administrators and users a powerful flexible standard remote interface while the automobile is often the primary remote access tool of other OS administrators (e.g. Windows XP).

B. History of Linux
Linux evolved from a kernel created by Linus Torvalds when he was a student at the University of Helsinki. When Linus Torvalds was studying at the University of Helsinki, he was using a version of the UNIX operating system called ‘Minix’. Linus and other users sent requests for modifications and improvements to Minix’s creator, Andrew Tanenbaum, but he felt that they weren’t necessary. That’s when Linus decided to create his own operating system that would take into account users’ comments and suggestions for improvements. Late in 1991, Linus Torvalds had his kernel and a few GNU programs wrapped around it so it would work well enough to show other people what he had done.

C. The Kernel

The kernel is at the heart of the Linux/Unix operating system. It is responsible for enabling multi-tasking, multi-user, multi-threading, multi-processing, security, interfacing with hardware and the network. It is this kernel which Linus Torvalds developed, based on the POSIX/Unix design, which gives Linux its name. Shells, user applications and everything else interfaces with this kernel.

D. Why to Use Linux
Comparing Ms Windows Operating Systems, Linux avoids the MS/Windows “DLL libraries”, which causes Windows or its applications to fail when a newer or incompatible run-time dynamic linked library (DLL) is installed. Linux employs version numbers in its run-time shared object libraries, which can therefore coexist on the system with different versions of the same libraries. The Linux RPM package management system, for example, helps resolve dependencies and conflicts with files and libraries.
Network settings and many other MS/Windows parameters require a reboot to take effect. This is also true when MS/Windows registry settings are modified. Linux is modular enough to allow the particular service (i.e. networking) to be cycled without shutting down the entire computer. Linux also has many kernel parameters which can be set through the “/proc/” interface to allow dynamic changes to a running kernel. This greatly increases Linux system uptime and eliminates the time wasted performing system reboots.
The file system directory structure is completely configurable and not limited to drive letters such as A, C or D as a top level mounts point. Thus MS/Windows has a limit of 23 mount points.
The Linux/Unix file system is network enabled (using NFS) to extend its reach. Both directly attached storage and networked file systems are mountable at any point in the file system directory hierarchy and can be simultaneously used by all users on the system.
The use of Linux/Unix pipes, tees and redirection allow a modular approach to the design of Linux/Unix tools. They allow the capability of any tool to be extended, chaining input and output with other tools.
Linux/Unix shell scripts provide a batch scripting capability which can be scheduled, propagated to other systems or used to create new commands. Only GUI interfaces may require physical point and clicks on each system to perform a task. While some debate GUI vs. commands and scripts, Linux/Unix embraces both.
Linux is an open source code which guarantees fast development.

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