Open Source Software (OSS) and its importance

Open Source Definition

The Open Source Definition is used by the Open Source Initiative to determine whether or not a software license can be considered open source.
The definition was based on the Debian Free Software Guidelines, written and adapted primarily by Bruce Perens. They are by no means definitive even as applied to software; Note that clause 3 is the primary legal difference between free software and open source software as such, free software is stricter in interpreting 3. Note also that clauses 5 and 6 are not a condition of any major open content license regimes, which commonly do restrict types of uses and users, for instance, Creative Commons has open content licenses that explicitly forbid commercial use.

Introduction

Open source doesn't just mean access to the source code.

The distribution terms of open-source software must comply with the following criteria:

1. Free Redistribution

The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.

2. Source Code

The program must include source code, and must allow distribution in source code as well as compiled form. Where some form of a product is not distributed with source code, there must be a well-publicized means of obtaining the source code for no more than a reasonable reproduction cost preferably, downloading via the Internet without charge. The source code must be the preferred form in which a programmer would modify the program. Deliberately obfuscated source code is not allowed. Intermediate forms such as the output of a preprocessor or translator are not allowed.

3. Derived Works

The license must allow modifications and derived works, and must allow them to be distributed under the same terms as the license of the original software.

4. Integrity of The Author's Source Code

The license may restrict source-code from being distributed in modified form only if the license allows the distribution of "patch files" with the source code for the purpose of modifying the program at build time. The license must explicitly permit distribution of software built from modified source code. The license may require derived works to carry a different name or version number from the original software.

5. No Discrimination Against Persons or Groups

The license must not discriminate against any person or group of persons.

6. No Discrimination Against Fields of Endeavor

The license must not restrict anyone from making use of the program in a specific field of endeavor. For example, it may not restrict the program from being used in a business, or from being used for genetic research.

7. Distribution of License

The rights attached to the program must apply to all to whom the program is redistributed without the need for execution of an additional license by those parties.

8. License Must Not Be Specific to a Product

The rights attached to the program must not depend on the program's being part of a particular software distribution. If the program is extracted from that distribution and used or distributed within the terms of the program's license, all parties to whom the program is redistributed should have the same rights as those that are granted in conjunction with the original software distribution.

9. License Must Not Restrict Other Software

The license must not place restrictions on other software that is distributed along with the licensed software. For example, the license must not insist that all other programs distributed on the same medium must be open-source software.

10. License Must Be Technology-Neutral

No provision of the license may be predicated on any individual technology or style of interface.

 

Funding

Unlike proprietary off-the-shelf software, which comes with restrictive copyright licenses, open-source software can be given away for no charge. This means that its creators cannot require each user to pay a license fee to fund development. Instead, a number of alternative models for funding its development have emerged.
Software can be developed as a consulting project for one or more customers. The customers pay to direct the developers' efforts: to have bugs prioritized and fixed or features added. Companies or independent consultants can also charge for training, installation, technical support, or customization of the software

Open source vs. closed source

The debate over open source vs. closed source (alternatively called proprietary software) is sometimes heated.
One source of conflict is related to economics: Making money through traditional methods, such as sale of the use of individual copies and patent royalty payment (generally called licensing), is more difficult and in many ways against the very concept of open source software.
Some closed-source advocates see open source software as damaging to the market of commercial software. This is one of the many reasons, as mentioned above, that the term free software was replaced with open source — because many company executives could not believe in a product that did not participate economically in a free-market or mixed-market economy.
The counter to this argument is the use of open source software to fuel the market for a separate product or service. For example:

• Providing support and installation services; similar to IT Security groups, Linux Distributions, and Systems companies.
• Using the software as a stepping stone to sell a higher-end product or service; e.g., OpenOffice.org vs. StarOffice.
• Cost avoidance / cost sharing: many developers need a product, so it makes sense to share development costs (X Window System and the Apache web server)

Since Open Source software is open, all of the defects and security flaws are easily found. Closed-source advocates argue that this makes it easier for a malicious person to discover security flaws. Further, that there is no incentive for an open-source product to be patched. Open-source advocates argue that this makes it easier also for a patch to be found and that the closed-source argument is security through obscurity, which this form of security will eventually fail, often without anyone knowing of the failure. Further, that just because there is not an immediate financial incentive to patch a product, does not mean there is not any incentive to patch a product. Further, if the patch is that significant to the user, having the source code, the user can technically patch the problem themselves. These arguments are hard to prove. However, research indicates that open-source software does have a higher flaw discovery, quicker flaw discovery, and quicker turn around on patches.

Open source software vs. free software

The main difference is that by choosing one term over the other (i.e. either "open source" or "free software") you let others know about what your goals are.
"As one person put it, 'Open source is a development methodology; free software is a social movement.'"
Critics have said that the term “open source” fosters an ambiguity of a different kind such that it confuses the mere availability of the source with the freedom to use, modify, and redistribute it. Developers have used the alternative terms Free/open source Software (FOSS), or Free/Libre/open source Software (FLOSS), consequently, to describe open source software which is also free software.

The term “Open Source” was originally intended to be trademarkable; however, the term was deemed too descriptive, so no trademark exists. The OSI would prefer that people treat Open Source as if it were a trademark, and use it only to describe software licensed under an OSI approved license.
OSI Certified is a trademark licensed only to people who are distributing software licensed under a license listed on the Open Source Initiative's list.

Open source software and free software are different terms for software which comes with certain rights, or freedoms, for the user. They describe two approaches and philosophies towards free software. Open source and free software (or software libre) both describe software which is free from onerous licensing restrictions. It may be used, copied, studied, modified and redistributed without restriction. Free software is not the same as freeware, software available at zero price.