Introduction to Linux

(work in progress)

Linux
(monolithic kernel)
(EDIT) just learned that Linux can be installed beside another operating system, and you can choose which to start when you start your computer

Unix- is a comperuter operating system originally developed in 1969 by a group of AT&T employees. aside from certified Unix systems (the most notable being, solaris, HP-UX, and AIX.) there Unix like operating systems

unix philosophy Unix was designed to be portable, multi-tasking and multi-user in a time-sharing configuration. Unix systems are characterized by various concepts: the use of plain text for storing data; a hierarchical file system; treating devices and certain types of inter-process communication (IPC) as files; and the use of a large number of software tools, small programs that can be strung together through a command line interpreter using pipes, as opposed to using a single monolithic program that includes all of the same functionality. These concepts are collectively known as the Unix philosophy.

Under Unix, the "operating system" consists of many of these utilities along with the master control program, the kernel. The kernel provides services to start and stop programs, handles the file system and other common "low level" tasks that most programs share, and, perhaps most importantly, schedules access to hardware to avoid conflicts if two programs try to access the same resource or device simultaneously. To mediate such access, the kernel was given special rights on the system, leading to the division between user-space and kernel-space.

Unix like computer


The Filesystem Hierarchy Standard was created to provide a reference directory layout for Unix-like operating systems, particularly Linux.
operating system

installed in a lot,
Usage share of web client operating systems.
Windows XP (45.47%)
Windows 7 (20.77%)
Windows Vista (16.90%)
Mac OS X (6.82%)
Linux (1.43%)
iOS (iPhone) (1.40%)

(supercomputers) http://upload.wikimedia.org/wikipedia/commons/0/0d/Operating_systems_used_on_top_500_supercomputers.svg

open source

minux
The other dedicated camp of computing was the Unixworld. But Unix itself was far more expensive. In quest of big money, the Unix vendors priced it high enough to ensure small PC users stayed away from it. The source code of Unix, once taught in universities courtesy of Bell Labs, was now cautiously guarded and not published publicly. To add to the frustration of PC users worldwide, the big players in the software market failed to provide an efficient solution to this problem.

A solution seemed to appear in form of MINIX. It was written from scratch by Andrew S. Tanenbaum, a US-born Dutch professor who wanted to teach his students the inner workings of a real operating system. It was designed to run on the Intel 8086 microprocessors that had flooded the world market.

As an operating system, MINIX was not a superb one. But it had the advantage that the source code was available. Anyone who happened to get the book 'Operating Systems: Design and Implementation' by Tanenbaum could get hold of the 12,000 lines of code, written in C and assembly language. For the first time, an aspiring programmer or hacker could read the source codes of the operating system, which to that time the software vendors had guarded vigorously. A superb author, Tanenbaum captivated the brightest minds of computer science with the elaborate and immaculately lively discussion of the art of creating a working operating system. Students of Computer Science all over the world pored over the book, reading through the codes to understand the very system that runs their computer.


popularity

design

user interface

super computers

Gnu
The GNU Project, started in 1983 by Richard Stallman, had the goal of creating a "complete Unix-compatible software system" composed entirely of free software. Work began in 1984.Later, in 1985, Stallman started the Free Software Foundation and wrote the GNU General Public License (GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, compilers, text editors, a Unix shell, and a windowing system) were completed, although low-level elements such as device drivers, daemons, and the kernel were stalled and incomplete.[18] Linus Torvalds has said that if the GNU kernel had been available at the time (1991), he would not have decided to write his own. (Linux filled the kernel gap, under version 2 of the GNU GPL)

Free software

The GNU project uses software that is free for users to copy, edit, and distribute. It is not always free in cost, but it is free in the sense that users can change the software to fit individual needs. The way programmers obtain the free software depends on where they get it. The software could be provided to the programmer from friends or over the internet, or the company a programmer works for may purchase the software. Proceeds from purchases support the GNU project. GNU has four kinds of freedom for the software:

* Freedom to run the program
* Freedom to access the code
* Freedom to redistribute the program to anyone
* Freedom to improve the software[8]

Copyleft

Copyleft is what helps maintain free use of this software among other programmers. Copyleft gives the legal right to everyone to use, edit, and redistribute programs or program's code as long as the distribution terms do not change. Copyleft preserves the freedom in new code and programs.




Linux Wikipedia
Linux Naming Controversy wikipedia
Linux Kernel Wikipedia
(history of linux)
Linux history, (Linux Website)
Linux history, (VERY GOOD)
History of Linux wikipedia
(understanding linux)
Linux info
(the big 3)