Abstract: An electronic calculator includes modular read-write and read-only memory units, a central processing unit, an output display unit, an output printer unit, a keyboard input unit, and input/output interface circuitry for facilitating the connection of one or more peripheral input/output units, such as an X-Y plotter, for example, to the calculator. When the calculator is coupled to an X-Y plotter, the user may employ commands entered from the keyboard input unit to move the plotter pen to an arbitrary position on the plotter platen whose X and Y coordinates are unknown to him and to subsequently cause the calculator to determine and display the X and Y coordinates of that arbitrary pen position.

Abstract: An adaptable programmable calculator employs modular read-write and read-only memories separately expandable to provide additional program and data storage functions within the calculator oriented toward the environment of the user, an LSI NMOS central processing unit, and LSI NMOS peripheral interface adaptor capable of bidirectionally transferring information between the read-write memory and central processing unit and a number of input/output units. The input/output units include a keyboard input unit with a plurality of alphanumeric keys, a magnetic tape cassette reading and recording unit capable of bidirectionally transferring programs and data between a magnetic tape and the calculator, a seven-segment gas discharge display, and a 16-column alphanumeric thermal printer.

Abstract: An adaptable programmable calculator employs modular read-write and read-only memories separately expandable to provide additional program and data storage functions within the calculator oriented toward the environment of the user, an LSI NMOS central processing unit, and an LSI NMOS peripheral interface adaptor capable of bidirectionally transferring information between the read-write memory and central processing unit and a number of input/output units. The modular read-write memory includes a movable boundary between a program storage section thereof and a data storage section thereof to permit the user to adjust the size of those sections of the read-write memory in accordance with his present problem solving requirements.