Programmable calculator

摘要

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, and an LSI NMOS central processing unit, which includes the capability of bidirectionally transferring information between itself and various input/output units. The input/output units include a keyboard input unit having a full complement of alphanumeric keys, a magnetic tape cassette reading and recording unit capable of bidirectionally transferring programs and data between the calculator and a magnetic tape, a 32-character solid state output display unit capable of displaying every alphabetic and numeric character. The calculator employs a natural algebraic program language that allows the user to enter lines of one or more alphanumeric algebraic statements into the calculator from the keyboard input unit while visually observing each line as it is entered to check for errors therein. The user may immediately execute each entered line or store that line as part of a program in the read-write memory, may subsequently recall the executed or stored line so that it may be reinspected, and, if necessary, edited and re-executed or re-stored, thereby automatically replacing the previously stored line. The program language of the calculator is contained within a plug-in language read-only memory and may be changed by inserting a different language read-only memory.