Abstract: A device for teaching computer operation and programming by simulating computer operation is disclosed in which all components are mounted on a planar base member. The program is written in addressable storage compartments on a single, detachable program storage member. This permits reprogramming by simply interchanging program storage members. Main, random access, storage is also provided by an appropriately compartmented, detachable storage member. During operation, data input and output are written on detachable members so that a record of these is available. Similarly, internal operational registers incorporate detachable members on which information is written during operation, so that a record is also available of all internal operations. The training device also includes at least one jump switch which the operator can set to any of a plurality of different states.