  This document explains the basic concepts related to software and hardware
licenses, and it summarizes the most popular licenses that are currently used
for hardware projects. Two case studies of hardware projects at different
levels of abstraction are also presented, together with a discussion of license
applicability, commercial issues, code protection, and related concerns. This
paper intends to help the reader understand how to release open hardware with
the most appropriate license, and to answer questions that are of current
interest. We have been mainly motivated by the growing influence of the open
RISC-V ISA, but trying to address a wider hardware point of view.
