Free software (open source software, free software, also software libre or libre software), free software - software whose users have rights (“freedoms”) for its unlimited installation, launch, free use, study, distribution and change ( improvement), as well as distribution of copies and results of the change. If the software has exclusive rights, then freedoms are declared using free licenses.

In European culture, long developed rules of ownership in relation to material values. And it is quite logical that these rules were extended to intangible values ​​- including software products, when they began to be of independent value. However, software products have a fundamental difference from material objects - they can be easily copied. Making a copy of a material product is often almost equal to the cost of creating the original.

Because of this difference for the software does not apply the principle of "use the thing at the same time can only be one person" (and its use by someone else automatically deals the first damage due to non-receipt of benefits from it) on account of which there is a concept of "master." Therefore attempt and then act on this principle - secure the right to use the program for a some man - is perceived intuitively [10] as being contrary to the nature of things. Not surprisingly, there is a lot of turmoil, each of which must be solved with artificial and often unnatural methods.

For example, it is necessary to simulate the "damage due to non-receipt of goods", which "applied", "master" program when it bezuscherbnom copy or refund if an error is detected and the defects in the programs. Usually it is - "loss of profit", that is, the profit that the owner could get, but have not received due to the fact that the product is copied. Have to invent an ingenious apparatus that interferes with copying or causes damage at the same time. To introduce into the legislation a special category of rights - conditional call it "patent" [11] - to limit the abuses - and freedom - all of humanity for the benefit of the owner of the patent. And not always the owner of the patent and the inventor - one and the same person (in such cases, the unnaturalness of these measures is only compounded).

Non-free programs are called “proprietary” (from the English proprietary) or “proprietary”. Sometimes they are incorrectly called, simply, “commercial”, which is wrong: you can benefit from the program in various ways, and many successful free projects confirm this.