Sequence control of analogue computers

Parallel-logic programming of analogue computers often presents difficulties to all but the most experienced users. The paper describes an inexpensive method of simplifying the control of iterative problem solutions run on parallel-logic analogue computers by employing a special-purpose sequence controller. The controller stores up to 16 64 bit words, which are transferred in sequence to an output buffer. Most of the bits within each word form the control signals for analogue components. This is mechanised by connections from the controller-output buffer to the analogue-component control lines via an existing parallel-logic patchboard. Conditional (i.e. comparator-controlled) operations and manual control (using logic switches) are possible with only a limited number of analogue components. A compiler for a digital computer enables the user to define the modes and states of analogue components as a sequence of events in time. These events, and the periods of time between them, may be defined by a list of digital-program-source statements, or, conversationally, by replying to questions typed at the user´s teleprinter. Either form of input is compiled into the sequence-controller machine code, which is then loaded into the controller memory ready for execution.