Two Approaches for Increasing Storage Density in Modern Digital Computing Systems

Modern digital computing systems are primarily limited in how densely information may be recorded on the magnetic storage elements by the manner in which the information is retrieved (detected) from these storage facilities. Current systems store information at a density around 1000 bits per inch (bit/in); system elements, other than the detection process, could easily handle densities in excess of 3000 bit/in. This paper describes the signal present at the output of the read-write head and suggests two systems by which detection at high bit densities may be accomplished. The error rate associated with each system is given and the results are applied to a computer system using a magnetic disk file as the storage element. It is demonstrated that these detection procedures can meet the widely accepted standard of one error in one billion bits at reasonable signal-to-noise ratios.