Storage Requirements for a Message Switching Computer

A mathematical model which utilizes queuing theory is devised for estimating the storage requirements of a message switching computer. Since the storage needed for a message is proportional to the message length, the familiar derivation of a queue distribution in terms of the number of messages is not applicable. Instead the composite queue, resulting from a number of sending lines, is developed in terms of fixed size units. This is normally distributed with mean and variance given as functions of the load factors of the sending lines. Occurrences of machine failures due to insufficient storage capacity are then shown, on certain assumptions, to be exponentially distributed. The method involves bold simplifications at a number of points with resulting errors which are moderate and in the direction of safety. The application to concrete problems is illustrated.