Proprietary
Proprietary software refers to software that is owned and controlled by a specific individual or organization. The source code of proprietary software is typically kept private and is not available for viewing, modification, or redistribution by users. Proprietary software is distributed under specific terms and conditions set by the software owner, often requiring users to purchase licenses or adhere to usage restrictions. Examples of proprietary software include Microsoft Office, Adobe Photoshop, and Oracle Database.
Open Source
Open source software is released under a license that grants users the freedom to access, use, modify, and distribute the source code of the software. Open-source software encourages collaboration and allows users to contribute to the improvement of the software. There are different types of open-source licenses, each with its own specific terms and conditions.
Public Domain: Public domain refers to a category of software or creative work where the copyright has expired or never existed. Works in the public domain can be freely used, modified, and distributed by anyone without any restrictions. Public domain software is not subject to copyright laws, and there are no limitations on its usage.
Permissive: Permissive open source licenses, such as the MIT License and the Apache License, are licenses that impose minimal restrictions on the usage and distribution of the software. These licenses allow users to modify, distribute, and use the software, often without requiring derivative works to be released under the same license. Permissive licenses provide users with a high degree of freedom in using open-source software.
GNU Lesser General Public License (LGPL): The GNU Lesser General Public License (LGPL) is an open-source license developed by the Free Software Foundation (FSF). The LGPL is similar to the GNU General Public License (GPL) but provides additional permissions to link LGPL-licensed software with proprietary software. The LGPL allows developers to use LGPL-licensed libraries in their proprietary software without requiring the entire application to be released under the GPL.
In summary, while proprietary software is privately owned and its source code is restricted, open-source software allows users to access, modify, and distribute the source code. Public domain software has no copyright restrictions, permissive licenses provide flexibility, the LGPL allows linking with proprietary software, and copyleft licenses ensure the preservation of open-source principles.