A general purpose sequencing and timing computer with a program capacity of 100 instructions is described. Program storage is by means of a low cost shift register memory. Input, output, and branching instructions are provided, along with a novel instruction for the creation of ``DO'' loops. Complex pulse patterns with pulse durations ranging from 1 &mgr;sec to arbitrarily long times can be easily programmed. Up to eight external devices can be controlled without additional demultiplexing.