"My pc thinks it's a MAINFRAME!". This is the mainframe, you still need an operating system like MVS or z/OS to run job's and applications like a true IBM mainframe. You can use the Hercules to learn mainframe assembler with z/Architecture Principles of Operation from IBM site. Not easy to a begginer to start using it. You will still need wc3270 to access zOS. Truly amazing stuff!
Fast and simple.
A nice emulator to get old (and new) large iron software (called mainframe software) running on a PC or Mac.