If you want a simple and easy introduction to stepper motors, check out the [IMSAI Guy ... Alas, he cuts out the part where the source code is compiled and the 22V10 is programmed, and jumps ...

The purple boards slotted into the pairs of SIL headers are Pololu Stepper motor drivers. Going this route makes replacing a burnt out chip as easy as plugging in a new module. The terminal block ...