A comparison of computers

A routine simulating the operation of an analog computer was constructed for use on a digital computer at the Jet Propulsion Laboratory. This code, called DEPI,1 as an abbreviation for ¿differential equations pseudocode interpreter,¿ provides much of the flexibility and ease of operation associated with analog computer operation. A study was made in which the speed, accuracy, and flexibility of the DEPI system were compared with those attributes in a digital differential analyzer, an analog computer, and a digital computer. The vehicle of comparison was a zero-lift, zero-angle-of-attack missile-trajectory problem. The results of this comparison are presented here in tabular and graphical form. Because of variations which exist among commercial models of each type of computer used in the study, the salient features of the particular models are described.