Introducing Simulation

Emulation and simulation are two very similar concepts. Simh which is what allows you to experience the PDP-11 is a simulator. Wikipedia differentiates the two this way:

"It has recently become common to use the word "emulate" in the context of software. However, before 1980, "emulation" referred only to emulation with a hardware or microcode assist, while "simulation" referred to pure software emulation.[24] For example, a computer specially built for running programs designed for another architecture is an emulator. In contrast, a simulator could be a program which runs on a PC, so that old Atari games can be simulated on it. Purists continue to insist on this distinction, but currently the term "emulation" often means the complete imitation of a machine executing binary code while "simulation" often refers to computer simulation, where a computer program is used to simulate an abstract model. Computer simulation is used in virtually every scientific and engineering domain and Computer Science is no exception, with several projects simulating abstract models of computer systems, such as network simulation."

Simh is also what is called a console program. Unlke Windows or OS X there is no GUI (Graphical User Interface). To tell Simh what to do, you need to type commands. This is known as a CLI (Command Line Interface). It should also be noted that all of the Models and Operating Systems that are simulated use a CLI. Don't be intimidated because every configuration comes with detailed instructions.

To learn more, please go to [Introducing the PDP-11]