Beam-Positioning Servo System for the Flying Spot Store

The flying spot store, a large, high-speed semipermanent memory, lias been described by Hoover, Staehler and Ketchledge. 1 They have discussed the fundamental concepts and purposes of such a store and have clearly indicated t h a t an essential feature of such a store is a servocontrolled positioning system. One form of such a positioning system has been described by them. This paper will consider to a greater extent the forms such systems may take and their relationship to the design objectives of the store. 1.1 System Objectives Although the specific system environment for which the store designs were executed is a telephone switching system, 2 the use of the store in more general real-time data processes imposes very similar requirements. The use for which the highest speed of operation is required in the telephone switching application is for real-time operation from a stored program. Random access to tabular information, although needed rapidly, is not usually controlling because of the more infrequent reference. In the case of program information, two important access actions can be distinguished. The first and most common is a sequential access, stepping word by word along the program; the second is a random access occasioned by transfers to other parts of the program or to subprograms. 425