Are there any Hybrids to these systems?

Yes, Open Source allows anyone to modify the code and create their own system. Generally, a manufacturer takes Open Source technology and modifies it for resale. Due to the licensing agreement of Open Source technology, any part of the code modified for the new technology should be freely available as well. This is called the ‘copy-left’ system (as opposed to copyright). However some manufacturers like Apple open only certain parts of the code to the public that they took to create the whole system. Yes, its true, Apple is actually based on Open Source technology based on BSD UNIX. Darwin is the name of the semi-open version of BSD UNIX that Apple uses.

Other hardware manufacturers also use a Hybrid Open Source system for resale such as:

• Linksys – A Router manufacturer who was just bought out by Cisco Systems.
• Citrix NetScaler – A product of Citrix.