In OS X, lurking beneath the pretty graphics is a complete Unix operating system based on FreeBSD, including support for X-windows. Most of the open-source software developed for Linux/FreeBSD has been ported to OS X, so for the Unix fans (like me), the operating system can look like Unix with a great graphical interface that also runs Macintosh applications. Overall, OS X is a very impressive desktop/laptop operating system.
All Generation 4 OS X distributions require OS X 10.10 (Yosemite) or later.
The Whiteley Research programs presently require that the X-windows server be running, as X is used for graphics. Unlike in some earlier OS X releases, it is not installed automatically in Yosemite. The Apple-sponsored X-server is called "XQuartz" and is available for download from the project web site (google ``XQuartz download'').
Operation and behavior should be identical to the Unix/Linux versions of the programs. These are 64-bit binaries.