LINUX in Operating System

Features of modern OS

• Provide a user interface
• Organize files on disk 
• Allocating resource to different users with security control 
• Co-ordinate programs to work with devices and other programs

Before Linux

• In 80's, Microsoft's DOS was the dominated OS for PC
• Apple MAC is better, but expensive
• UNIX is much better, but much much expensive. Only for minicomputer for commercial applications
• People were looking for a UNIX based system, which is cheaper and can run on PC
• Both DOS, MAC and UNIX are proprietary, i.e., the source code of their kernel is protected
• No modification is possible without paying high license fees.

GNU project

• Established in 1984 by Richard Stallman, who believes that software should be free from restrictions against copying or modification in order to make better and efficient computer programs
• GNU is a recursive acronym for "GNU's Not Unix"
• Aim at developing a complete Unix-like operating system which is free for copying and modification
• Stallman built the first free GNU C compiler in 1991. But still, an OS was yet to be developed.

Beginning of Linux

• A famous professor Andrew Tanenbaum developed Minix, a simplified version of UNIX that runs on PC 
• Minix is for class teaching only. No intention for commercial use
• In sept 1991, Linus Torvalds, a second year student of Computer Science at the University of Helsinki, developed the preliminary kernel of Linux, known as Linux version 0.0.1

Confrontation and Development

• Message from Professor Andrew Tanenbaum
• " I still maintain the point that designing a monolithic kernel in 1991 is a fundamental error. Be thankful you are not my student. You would not get a high grade for such a design :-)" " Linux is obsolete".

Linux Pros and Cons

Advantages over Windows

• It's almost free to relatively inexpensive
• Source code is included
• Bugs are fixed quickly and help is readily available through the vast support in Internet
• Linux is more stable than Windows.

Disadvantages compared with Windows

• My program cannot run on Linux
• Isn't as popular as Windows
• No one commercial company is responsible for Linux
• Linux is relatively hard to install, learn and use