Open source software is called a software whose source code is freely distributed with a license to study, modify and further distribute to anyone for any purpose. Open source software is usually a team effort where dedicated programmers enhance the source code and share the community changes. Open source software provides such benefits to users because of its flourishing communities-
A software that is released services for free for usage and distribution but can not be modified because it does not have its source code is considered freeware. Freeware sources include Google Chrome, the Adobe Acrobat PDF Reader, Skype, etc.
A program which is originally free and which may also be provided to anyone, but which has to be paid for after a defined period of time is called shareware. Its source code is not available either and can therefore not be modified.
Software that can only be accessed after obtaining a developer 's license without charging for it is considered proprietary applications. These proprietary software can be owned by an individual or firm. The source code is mostly closely guarded and may have major restrictions such as–
Microsoft Windows, for example, is a proprietary operating software that comes in many versions for different types of clients such as single-user, multi-user, professional, etc.