A permissive licence simple and is the most basic type of open source licence.It provides the software check usage, with no warranties. It however, requires developers to acknowledge the author/contributor.
BSD licences are a family of permissive free software licences.These impose minimal restrictions on the use and distribution of the software.Following are the latest three versions of the BSD licenses:
Zero-Clause:It is the latest of BSD licences.It was published in 2006.It was initially approved under the name,"Free Public licence 1.0.0".Zero-Clause BSD grants permission to use copy,modify,or distribute this software for any of purpose with or without a fee.This version of BSD does not require you to include the copyright notice,licence text,or disclaimer in either source or binary forms.
2-clause Licence or 'Simplified BSD Licence' or 'FreeBSD Licence':
The main difference between the 2-clause and the New BSD (3-clause) licence is that it omitted the non-endorsement clause and added a disclaimer about views and opinions expressed in the software.Also, it is compatible with the GNU GPL.
BSD 3-Clause or "New" or "Revised" Licence:
This version permits unlimited redistribution for any purpose as long as its copyright notices, and the licence's disclaimers of warranty are maintained.The version dropped the "Advertising Clause" from the previous version and added the non-endorsement clause which restricted the use of the names of contributors for endorsement of a derived work without specific permission.
MIT (Massachusetts Institute of Technology) grants permission to the user of the software the rights to use, copy, modify, merge, publish, distribute, sublicence,or sell copies of the software without any limitations and restrictions.
The only condition this licence is that the permission notice must be included in all copies of substantial portions of the software. Apache Licence Version is an open source software licence that provides a number of rights to users. These rights can be applied to both copyright and patents.
The rights to use, modify, sell, or reproduce a software that the Apache licence grants are:
Perpetual:These do not have an expiry date; you can continue to use them forever.
Worldwide:Rights granted in one country are recognised throughout the world.
Non-exclusive:
Multiple developers can be given the licence at the same time.
Free of Cost:
The rights are granted at no charge.
Royalty-free:
No royalty fee is charged on the sale of the modified versions of the software.
Irrevocable:
Rights, once granted,may not be retracted or repealed.
Copyleft Licences
Copyleft licences offer users the right to run, study, share, modify, and distribute copies and modified versions of the software with the condition that the same rights be preserved for its derivatives. Copyleft licences require that the source code must be made available to the recipients. The source code files usually contain a copy of the licence terms and acknowledge the authors.
GNU GPL (GNU General Public Licence):
General Public Licences are intended to guarantee the user's freedom to share and change all versions of a program, and to make sure it remains a free software for all its users.