History of Linux

                                                                                                                  BY  :  SNEHIT VADDI

In 1991, while studying computer science at University of Helsinki, Linus Torvalds began a project that later became the Linux Kernal. He wrote the program specifically for the hardware he was using and independent of an operating system because he wanted to use the functions of his new PC with an 80386 processor. Development was done on MINIX using the GNU C Compiler. The GNU C Compiler is still the main choice for compiling Linux today, but can be built with other compilers, such as the Intel C Compiler.

According to Torvalds, Linux began to gain importance in 1992 after the X Window System was ported to Linux by Orest Zborowski, which allowed Linux to support a GUI for the first time.

Events leading to creation of Linux
1.After AT&T had dropped out of the Multicsproject, the Unix operating system was conceived and implemented by Ken Thompson and Dennis Ritchie in 1969 and first released in 1970. Later they rewrote it in a new programming language, C, to make it portable.
2.In 1977, the Berkeley Software Distribution(BSD) was developed by the Computer Systems Research Group (CSRG) from UC Berkeley, based on the 6th edition of Unixfrom AT&T.
3.In 1983, Richard stallman started the GNU project with the goal of creating a free UNIX-like operating system.As part of this work, he wrote the GNU General Public License (GPL).But it failed to attract enough development effort, leaving GNU incomplete.
4.In 1985, Intel released the 80386, the first x86 microprocessor with a 32-bit instruction setand a memory management unit with paging.

Linux under the GNU GPL 

Torvalds first published the Linux kernel under its own licence, which had a restriction on commercial activity.

The software to use with the kernel was software developed as part of the GNU project licensed under the GNU General Public License, a free software license. The first release of the Linux kernel, Linux 0.01, included a binary of GNU's Bash shell.

In the "Notes for linux release 0.01", Torvalds lists the GNU software that is required to run Linux.

In 1992, he suggested releasing the kernel under the GNU General Public License. He first announced this decision in the release notes of version 0.12. In the middle of December 1992 he published version 0.99 using the GNU GPL. Linux and GNU developers worked to integrate GNU components with Linux to make a fully functional and free operating system.Torvalds has stated, "making Linux GPL'd was definitely the best thing I ever did.

ARCHITECTURE OF LINUX

Linux is one of popular version of UNIX operating System. It is open source as its source code is freely available. It is free to use. Linux was designed considering UNIX compatibility. It's functionality list is quite similar to that of UNIX.

Components of LINUX

Linux has the following components of a typical OS

• KERNEL
• SHELLS AND GUI'S
• HARDWARE
• APPLICATION PROGRAMS

  

KERNEL :

  

The Linux kernel incudes device driver support for a large number of pc hardware(graphic cards, network cards, hard disks),advanced processor and memory management features and support for many different types of file systems. The kernel is core of the operating systems—a collection of routines mostly written in C. It is loaded into memory when the system is booted and communicates directly with the hardware. User programs that need to access the hardware use the services of kernel, which performs the job on the user’s behalf. These programs access the kernel though a set of functions called as system calls.

Apart from providing the support to user programs, the kernel has a great deal of housekeeping to do.it manages the systems memory, schedules process, decides their priorities, and performs other tasks which wouldn’t like to bother about. The kernel has to do a lot of work even if there is no user programs running.

SHELLS :

    

   Computers don’t have any inherent capability of translating commands into action . That requires a command interpreter, a job is handled by the “outer part ” of operating system which is known to be called as shells. LINUX supports two forms of command input through textual command shells which are similar to found on most of the LINUX system and through graphical interfaces such as KDE and GNOME managers. Shells are generally the interface between user and the kernel. Even though there is only one kernel running on the system, there could be several shells in action(one for each user who is logged in).

APPLICATION PROGRAMS :

LINUX distribution typically come with several useful application programs as standard. Examples include the emacs editor, Xv image viewer gcc compiler; g++  which is a compiler for c++ ,later and soffice which is an MS-OFFICE style that can read and write WORD,EXCEL and POWERPOINT files .

Reference:
1)    https://googleweblight.com/i?u=https://en.m.wikipedia.org/wiki/History_of_Linux&hl=en-IN#a.cite_note-fun-13

2) https://www.digitalocean.com/community/tutorials/brief-history-of-linux