Chapter 3 GPL and Copyleft!

GPL:- What is GPL?

The term GPL has a great importance in the world of Open Source. The General Public License (GNU GPL or simply GPL) is a widely used free software license, originally written by Richard Stallman for the GNU project. Linux is written and distributed under the GNU General Public License which means that its source code is freely-distributed and available to the general public.

The licenses for most software in Microsoft Windows are designed to take away your freedom to share and change it   By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software to make sure the software is free for all its users .

What is Copyleft:-

Copyleft is a play on the word copyright to describe the practice of using copyright law to remove restrictions on distributing copies and modified versions of a work for others and requiring that the same freedoms be preserved in modified versions. Copyleft says that anyone who redistributes the software, with or without changes, must pass along the freedom to further copy and change it. Copyleft guarantees that every user has all the freedom as mentioned in the previous post. You may charge money for all this too.

Your name will stay for ever in the license

All rights reversed.

Only restriction on a first review is “You cannot change or alter the license”

List of Free and non Free licenses are listed at

http://www.gnu.org/licenses/license-list.html

A comparison of Open Source Licenses can be found at http://developer.kde.org/documentation/licensing/licenses_summary.html

Chapter 2 Why Linux is important?

Linux has its own importance nowadays days due to the following reasons, which other OS’s may not have !

1. Freedom’s in Linux :-

If you have been following the Open Source movement, you know I am not talking about the price of the software when I say freedom.

Free not as in free drinks. But Free as in Freedom or Free speech. In most cases, you get free drinks though

Freedom 0 – The freedom to run the program, for any purpose :-
Yes, the users have the freedom to run the program for any purposes like software development, animation, designing, desktops etc. We can run the program without any prior license from any authorities.

Freedom 1 – The freedom to study.
In Linux we have got the freedom to study how the program works, and adapt it according to our needs. Access to the source code is a precondition for this, which is allowed in Linux.

Freedom 2 – The freedom to redistribute the copies.
We can distribute our copy of linux through dvd’s, pen-drives etc, so that we can help our neighbor & fellow human beings.

Freedom 3 – The freedom to improve the program.
Since we have the access to the source code, we can modify it and release our improvements to the public, so that the whole community benefits.

A program is free software if users have all of these freedoms.

And for a desktop user, most importantly, the freedom from viruses, as long as you use the software downloaded from the software repository of your OS

2. Multi-User Environment:-

Linux supports multi-user enviornment, ie several users are allowed to login to the same system with different permissions.

3. Potability :-

Linux is  portable. It is possible to reuse the existing code instead of creating new code when moving software from an environment to another. The portability is the key issue for development cost reduction.

4. Intimate knowledge of the hardware :-

Noting better than Linux to know your machine’s hardware information. A detailed information could be seen using a command ‘lspci’.(use option -vvv for more detailed info)

supportsage@supportsage-desktop:~$ lspci
00:00.0 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
00:00.1 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
00:00.2 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
00:00.3 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
00:00.4 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
00:00.7 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
00:01.0 PCI bridge: VIA Technologies, Inc. VT8237 PCI bridge [K8T800/K8T890 South]
00:0f.0 IDE interface: VIA Technologies, Inc. VIA VT6420 SATA RAID Controller (rev 80)
00:0f.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8237 ISA bridge [KT600/K8T800/K8T890 South]
00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233/A/8235/8237 AC97 Audio Controller (rev 60)
00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 [Rhine-II] (rev 78)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
01:00.0 VGA compatible controller: VIA Technologies, Inc. S3 Unichrome Pro VGA Adapter (rev 01)

An example for more detailed hardware information is given below.

supportsage@supportsage-desktop:~$ lspci -vvv
00:00.0 Host bridge: VIA Technologies, Inc. K8M800 Host Bridge
Subsystem: VIA Technologies, Inc. K8M800 Host Bridge
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
Status: Cap+ 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort+ >SERR- <PERR-
Latency: 8
Region 0: Memory at e8000000 (32-bit, prefetchable) [size=128M]
Capabilities: <access denied>

5. No BSOD – Blue Screen of Death :-

The BSOD is a colloquialism used for the error screen displayed by some other operating systems. And a Linux based system is free from this.

6. Upgradeability :-

The Linux systems could be upgraded quite easily, with the help of on-line repositories. Upgradation is possible without any changes in the system configuration and saved data’s.

7. Customization :-

Linux machine can be easily customised accourding to the user expectations. I leave , how to customise Linux to your imagination.

8. Security – viruses, worms and trojans :-

Linux machines are well known for its security. 65% of the server are running on Linux based machines. Linux machines are very less infected by viruses, worms and trojans.

9. Maturity – Stable, Reliable and Extremely powerful :-

Another fine reason for using server’s based on Linux is its ‘stability’ & ‘reliability’. No reboot is needed, except for kernel upgrades. OS like windows XP need a reboot, even a new application software is installed.

10. Support :-

You can get support for Linux from millions of forums, live IRC’s and even from your local LUG(Linux User Group). All are there to help you

11. Complete development environment :-

A C compiler for Windows alone would set you back hundreds of dollars. Whereas in Linux, most of the development libraries like gcc, perl, python, javac etc comes built-in.