Logisim
Logisim is an educational tool for designing and simulating digital logic circuits. With its simple toolbar interface and simulation of circuits as you build them, it is simple enough to facilitate learning the most basic concepts related to logic circuits. With the capacity to build larger circuits from smaller subcircuits, and to draw bundles of wires with a single mouse drag, Logisim can be used (and is used) to design and simulate entire CPUs for educational purposes.

A list of features:
  • The drawing interface is based on an intuitive toolbar. Color-coded wires aid in simulating and debugging a circuit.
  • The wiring tool draws horizontal and vertical wires, automatically connecting to components and to other wires.
  • It's very easy to draw circuits!
  • Completed circuits can be saved into a file, exported to a GIF file, or printed on a printer.
  • Circuit layouts can be used as "subcircuits" of other circuits, allowing for hierarchical circuit design.
  • Included circuit components include inputs and outputs, gates, multiplexers, arithmetic circuits, flip-flops, and RAM memory.
  • The included "combinational analysis" module allows for conversion between circuits, truth tables, and Boolean expressions.

System requirements
  • Minimum JRE: 1.6.0

Logisim on an eComStation machine with Open JDK


Installing Logisim
Download logisim-generic-2.7.1.jar. Create a directory (folder) "Logisim". Copy the jar file to this directory. That's it!

The logisim.cmd file
Logisim works with Open JDK in OS/2-eCS. I have made a logisim.cmd file with the following contents; 
@echo off
set path=[drive: java]\JAVA160\bin
set BEGINLIBPATH=[drive: java]\JAVA160\bin
set CLASSPATH=
[drive: logisim]
cd [drive: logisim]\Logisim
java -Duser.home=[drive: logisim]\Logisim -jar logisim-generic-2.7.1.jar 2>logisim-bugs.txt
I use 2 separate folders (directories), one for Java and one for Logisim with the files created by this program. The references used in the cmd file;

  • [drive: java] = drive with Java
  • [drive: logisim] = drive with Logisim

should be replaced with real drive letters. Edit and save the file "logisim.cmd" from the distribution. This file is copied to the "Logisim" directory (folder). Furthermore, different paths?, adjust according to your needs.
Create a new program object. Specify the path and file name: "[drive: logisim]\Logisim\logisim.cmd". In the tabpage Session check the boxes "OS/2 window", "Running as an icon" and "Close Window to end program". In the tabpage General you can enter the name "Logisim". You find enclosed in the file a suitable OS/2 icon.

Parameters / options explained
  • The addition "2>logisim-bugs.txt" ensures that errors are saved in the file "logisim-bugs.txt". The 2 in "2>" is not a typo!
  • The specification "-Duser.home=[drive: logisim]\Logisim" ensures that Logisim will save all necessary files in own directory instead of saving them in the home directory.

Download
In the file you can find the above command file (all driveletters are set to C:) and an OS/2 Logisim icon: logisim-ecs.zip.

revision June 11, 2016