This is a simple tutorial on irsim. It is not meant to replace the irsim manual which contains much more information. Try man irsim for information on all the commands that irsim supports. Typically we will first use Magic to layout a circuit and then extract the circuit description and analyze it with irsim. For example it permits a transistor level design to be tested quickly, before a layout is generated.
Irsim files are just text files that contain information about a circuit.
They have the extension .sim. The first time you use irsim, you will probably have to create the .sim file yourself using your favorite text editor. The first step in creating a .sim file for this circuit is to label all the nodes. Label power Vdd and ground Gnd . Irsim is not case sensitive so vdd and gnd will work also.