A Note on the System Requirements of a Digital Computer for the Manipulation of List Structures

The technique of programming within the framework of the so-called Newell-Shaw-Simon (NSS) associative list memory is currently the subject of much interest among workers in the area of advanced programming research. Unfortunately, committing a given program to list memory generally entails accepting a significant loss of speed and efficiency in information processing, so that the advantages accruing from the use of list memory must be carefully balanced against its weaknesses. This paper is concermed with the system requirements of a digital computer for which the use of list techniques is to be competitive with standard programming, so that the particular memory organization for a given problem may be chosen on the basis of suitability and ease of programming alone. A description of a list-processing 7090-type computer is appended in order to make our discussion concrete, although engineering and economic feasibility is not implied.