(by 2 people)
The term "open source" means a lot of things to a lot of people. The goal of this lens is to give a short background on open source software and provide a list showing the wide variety of available open source software.
Some Background
A few terms you might want to know
The following terms are very general definitions (not in alphabetical order):
Software -- A computer program
Source code -- The human-readable instructions that make a computer program. These instructions are converted into "machine code" by a compiler.
Machine code -- The instructions that your computer actually performs.
License -- A legal contract that details the user's rights (or lack thereof) related to some work. With software, most licenses do not allow the user to see the source code, or even use special programs called "decompilers" to discover how the program works. Users are also typically not allowed to redistribute the program.
Decompiler -- A program that tries to convert machine code back into source code.
Software -- A computer program
Source code -- The human-readable instructions that make a computer program. These instructions are converted into "machine code" by a compiler.
Machine code -- The instructions that your computer actually performs.
License -- A legal contract that details the user's rights (or lack thereof) related to some work. With software, most licenses do not allow the user to see the source code, or even use special programs called "decompilers" to discover how the program works. Users are also typically not allowed to redistribute the program.
Decompiler -- A program that tries to convert machine code back into source code.
Open Source Software
What does it mean?
Depending on who is describing the software, open source could mean:
1) software in which the user is allowed to see, but not modify or distribute, the source code
2) software that is legally protected by an open source license allowing users to freely modify and distribute the source code, or whose source code is in the public domain (i.e., not protected by any copyright)
Many software corporations are fond of the first description. It allows them to claim their software is "open source" in an attempt to project an image of goodwill in the software development community. This lens will focus on software fitting the second description.
1) software in which the user is allowed to see, but not modify or distribute, the source code
2) software that is legally protected by an open source license allowing users to freely modify and distribute the source code, or whose source code is in the public domain (i.e., not protected by any copyright)
Many software corporations are fond of the first description. It allows them to claim their software is "open source" in an attempt to project an image of goodwill in the software development community. This lens will focus on software fitting the second description.
Open Source Licenses
How "open" is "open"?
You might not be surprised to find out that even users of open source software disagree about exactly what it is.
1) Some people feel that software's source code should be guaranteed to be available to everyone. They propose special copyright licenses (sometimes called "copyleft") which requires that if anyone changes the software's source code and releases the application to the public, that application must also be covered under the same copyright. The most common example of this is the GNU General Public License (GPL). Many of these people refer to such software as "Free Software" instead, emphasizing the user's freedom to access, modify, and redistribute the software.
2) Other people feel that requiring modified software to be released as open source is a type of restriction per se. To them, the freedom to access the source code to the software belongs to the developer. Open source licenses of this type (such as the Berkeley Standard Distribution (BSD) License) allow those using the code to modify it and distribute applications without also distributing the source code.
3) Still others feel that all of these licenses are too much trouble and release their software and source code into the public domain. Works released into the public domain are not protected by any copyright, so users are completely free to modify or redistribute it under any terms.
1) Some people feel that software's source code should be guaranteed to be available to everyone. They propose special copyright licenses (sometimes called "copyleft") which requires that if anyone changes the software's source code and releases the application to the public, that application must also be covered under the same copyright. The most common example of this is the GNU General Public License (GPL). Many of these people refer to such software as "Free Software" instead, emphasizing the user's freedom to access, modify, and redistribute the software.
2) Other people feel that requiring modified software to be released as open source is a type of restriction per se. To them, the freedom to access the source code to the software belongs to the developer. Open source licenses of this type (such as the Berkeley Standard Distribution (BSD) License) allow those using the code to modify it and distribute applications without also distributing the source code.
3) Still others feel that all of these licenses are too much trouble and release their software and source code into the public domain. Works released into the public domain are not protected by any copyright, so users are completely free to modify or redistribute it under any terms.
Using Open Source
What's in it for me?
People use open source for a variety of reasons:
1) Some people are philosophically opposed to the concept of restrictive copyrights that prevent users from accessing and modifying code as they see fit.
2) Others think that open source is a better choice because it means the software is likely to be more secure or have fewer bugs since anyone with the knowledge can examine the inner workings of the program.
3) And others use it because it usually doesn't cost anything.
Most people use open source for a combination of these reasons. Some take a more pragmatic approach and will use proprietary, closed source software if they feel it is more suited to their needs, but a large number of open source advocates are quite dogmatic about their software choices.
1) Some people are philosophically opposed to the concept of restrictive copyrights that prevent users from accessing and modifying code as they see fit.
2) Others think that open source is a better choice because it means the software is likely to be more secure or have fewer bugs since anyone with the knowledge can examine the inner workings of the program.
3) And others use it because it usually doesn't cost anything.
Most people use open source for a combination of these reasons. Some take a more pragmatic approach and will use proprietary, closed source software if they feel it is more suited to their needs, but a large number of open source advocates are quite dogmatic about their software choices.
Open Source Software Organizations
- The GNU Project
- The GNU Project is one of the largest sources of free software around. They are the originators of the GNU General Public License (GPL).
- Open Source Initiative
- A group that advocates the use of open source software.
- Free Software Foundation
- A group promoting the use and development of free/open source software.
Open Source Software
Operating Systems
- Ubuntu Linux
- Ubuntu Linux is a popular version of the GNU/Linux operating system. This is the one I use at home.
- OpenBSD
- OpenBSD is a highly secure version of a type of unix operating system known as BSD. This is a popular option for those who want to run secure servers.
- Debian Linux
- Debian is as close to the "official" version of GNU/Linux as you can get. The applications that come with Debian are all under a GPL-compatible open source license.
Open Source Software
Science
These applications are great for amateur science buffs of all stripes!
- Celestia
- Amazing planetarium software! Celestia lets you explore the visible universe from the comfort of your computer room! Available for Linux and Windows.
- K3DSurf
- An application for modeling mathematical equations in 3D. Only runs on Linux.
- Stellarium
- This planetarium application focuses on the night sky from Earth. Amazing graphics and interface! Perfect for exploring the stars and constellations. Runs on Linux, Windows, and OS X.
Great Stuff on Amazon
Producing Open Source Software: How to Run a Successful Free Software Project
Amazon Price: $16.47 (as of 10/13/2008)
Understanding Open Source and Free Software Licensing
Amazon Price: $16.47 (as of 10/13/2008)
Open Source Software Law (Artech House Telecommunications Library)
Amazon Price: $86.35 (as of 10/13/2008)
