ENIAC Simulator

This is a pulse-level simulator of the ENIAC. The current state of the simulator covers all of the functionality as originally constructed at the University of Pennsylvania. Future plans include implementing the enhancements that were made at the Ballistics Research Lab during its operational life.

The simulator is discussed in some detail in Simulating the ENIAC. Further information on the ENIAC can be found here.

Build Instructions

The source code is divided into two main parts: the simulator core and the graphical visualization support. Source code for the simulator proper is in the src directory and that for the graphical support is in the vis directory. The graphical support is implemented as separate programs that run as child processes under the simulator core. With or without graphical support, the simulator provides a command-line interface for control.

Building the Core Simulator

Since the core is written in Go, you'll need the Go compiler installed. With that, go into the src directory and issue the command:

go build -o eniac

This will result in an executable called eniac that you can use to invoke the simulator Usually, things are run from the root of the repo, so if we want to run the prime number sieve in the programs directory, we could use the command:

src/eniac sieve.e

(Note that in some environments, you might have to use ./src/eniac.) The effect is that you will power up the machine with the configuration described in the file programs/sieve.e, and you will be greeted with a > prompt. To begin the computation, you need to press the Initiating Pulse Switch on the initiating unit. In the simulator you do this with the b i command. Doing so will cause the ENIAC to puch a series of cards, each holding a prime number in the range of 3 to 2801.

Building Graphical Support

At the present time, there are five different graphical support programs. Which one(s) will be useful to you depends on the details of your environment. They are as follows:

1. eniactk: the original graphical interface. It requires that you have TCL/Tk installed on your system and that the program wish be in your path. It uses the graphics in the images directory. As it is written in Go, you can compile it with the command go build -o eniactk eniactk.go or if you have make on your system, you can make eniactk.

2. eniacfp: provides a first-person video game type of interface. It uses the 3d model in the obj directory. To use this, you must have the Irrlicht library and a C++ compiler installed. It is built with the command make eniacfp.

3. eniac3d: very similar to eniacfp except that it renders the view from both eyes and presents them both. It's only useful if you have a video display system that supports 3d display. These displays usually require the use of LCD shutter glasses that alternate which eye is open, and the display switches between which frame is displayed. The command make eniac3d builds this one.

4. eniact5: another 3d experience. This one works with the AR system from Tilt Five and requires both the Irrlicht library and the Tilt Five native SDK. It is built with the command make eniact5.

5. ledmat: a driver for an LED matrix connected to a Raspberrhy Pi running Plan 9. Some discussion and a brief demonstration of this was presented at the 11th International Workshop on Plan 9.

To run the simulator with a graphical display, add the -v option to the command. For example, if we wanted to run the prime number sieve with the TCL/Tk graphical support, we'd use the command:

src/eniac -v vis/eniactk sieve.e

(assuming all the executables are in their respective source directories).