Open source software refers to programs where the source code is publicly available and can be modified. In 1991, Linux kernel was created by Linus Torvalds, providing a free UNIX-like kernel. When combined with the GNU operating system utilities, it formed a complete open source operating system called Linux. Major Linux distributions include SUSE, Debian, Mandrake, Caldera, and Red Hat. Red Hat Linux comes in both a free home edition called Fedora and a commercial edition called Red Hat Enterprise Linux. Linux is free, portable, secure, scalable, and has short debug times compared to proprietary operating systems like Windows.

1. Linux Ideas and History

2. What is Open Source?
• Open source: software and source code
available to all
• The freedom to distribute software and source
code
• The ability to modify and create derived works
• Integrity of author's code
• The Free Software Foundation and the Four
Freedoms

3. LINUX HISTORY
In 1965 Ken Thompson and Denis Ritchie developed UNIX.
Unix was very expensive. So in early 70’s big players
developed MINIX but this OS was not superb one like
UNIX.
In 1985 GNU project started this was free s/w movement,
means anyone can run, copy, distribute, study, change and
improve the software. Because of GNU project, GNU
utilities were there but Kernel was not present. At this
time, in 1991 LINUX TORVALDS Finland graduate student
wrote UNIX-like kernel or open source and today
Linux kernel + GNU utilities = complete open source Unix-
like operating system i.e. LINUX

4. Distributors of LINUX
1) SUSE
2) Debian
3) Mandrake
4) Caldera
5) Red Hat
6) Ubuntu

5. Red hat Linux
• Home edition, also known as FEDORA
New release duration is 6-8 months
• Commercial edition, also known as Red Hat
Enterprise Linux (RHEL)
New release duration is 18-24 months
• RHEL has 2 flavors
1) Server
2) Client

6. Features of LINUX
• Linux is free i.e. open source
• Linux is portable to any hardware platform
• Linux is secure and versatile
• Linux is scalable
• The Linux OS and most Linux applications have very
short debug-times
• It is case sensitive
• Multiuser multi-tasking
• Supports multi shell
• Modularity
• In Linux everything is file.

7. Windows Linux operating system
• Windows is closed source • Linux is open source
• It is not virus free • It is virus free
• Windows is less secure • Linux is more secure
• It is case insensitive • It is case sensitive
• Supports single shell • Supports multiple shell