free software is the one for which u need not pay and they may not give u the source code. but the open source software is the one for which u will get the source code.. btw an open source software can also be a free software....

When in doubt, get it from the horse's mouth. http://www.opensource.org/docs/osd The source code part of the definition is the part that sticks in most peoples' minds. Ultimately, free software that isn't open source is licensed in a way that still protects the creator from having to reveal how the program works. Open source allows for the improvement of software by other parties. The biggest myth about open source is that it is always free.

The main difference is that in order to qualify as open source, the code to the software must be freely available. Free software does not have that requirement and often chooses to exclude that info since it may be based on proprietary code that is also offered in a commercial version of a similar product.

It's basically the difference between free beer and free speech. Free requires no monetary payment. Open Source... well, I think it best if I paste straight form the horse's mouth ( http://opensource.org/docs/osd ) on this one. "The Open Source Definition 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." Note that section 1 does not prohibit charging money for software; not all open-source stuff is free.

Free software is free of cost. Open source software can be modified freely by programmers, may or may not be free of cost.

Free software is software that makes few or no restrictions on what you can do with it or the source code. According to the Free Software Foundation, in order for software to be considered "free", it must: Allow use of the program for any purpose. Have the source code available, to see how it works and change it. Allow you to distribute unmodified copies of the software Allow you to modify and release the changes to the program. "Open-source" software only needs to meet the second criteria. Software can have it's source available, but forbid you to release it commercially, or release modified copies of the binaries / source.