Linux

The Linux kernel was initially written as a hobby by Finnish university student Linus Torvalds while attending the University of Helsinki. Torvalds originally used Minix on his computer, a simplified kernel written by Andrew Tanenbaum for teaching operating system design. However, Tanenbaum did not support extensions to his operating system, leading Torvalds to write a replacement for Minix. Linux started out as a terminal emulator written in IA-32 assembler and C which was compiled into binary form and booted from a floppy disk so that it would run outside of any operating system. The terminal emulator was running two threads: one for sending and one for receiving characters from the serial port. When Linus needed to write and read files to disk, this task-switching terminal emulator was extended with an entire filesystem handler, and after that gradually evolved into an entire operating system targeted at POSIX-compliance. Linus implemented enough POSIX system calls to make Linux run the Bash shell and after this bootstrapping procedure the development rapidly sped up. Although a running Minix system was originally necessary in order to configure, compile, install and run Linux, the Linux system quickly surpassed Minix in functionality and was soon able to boot on its own and compile its own source code.

Linus Torvalds, creator of the Linux kernel

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Linus Torvalds, creator of the Linux kernel

The first version of the Linux kernel was released to the Internet in September 1991, with the second version following shortly thereafter in October [1]. Since then, thousands of developers around the world have participated in the project. Eric S. Raymond's essay The Cathedral and the Bazaar discusses the development model of the Linux kernel and similar software.

The history of the Linux kernel is closely tied to that of GNU, a prominent free-software project led by Richard Stallman. The GNU project was announced in 1983 for the purpose of developing a complete Unix-like operating system, including software development tools and user application programs, composed entirely