JLS is a logic simulator written specifically for this class by Dr. Poplawski. It is a Java program, and has been tested on Linux, Windows and Mac's. You can use the one installed in the CS labs by simply typing

(or better yet, make an alias for it so you don't have to type the entire full path), or you can get JLS for your own computer from here.

Once you have JLS installed on your machine, start it up and click on Help->About. You should have version 4.0.12. If you don't throw it away and get the right version.