Cost, Performance, and Size Tradeoffs for Different Levels in a Memory Hierarchy*

Abstract

Until recently, electronically addressable devices such as ferrite core, plated wire, semiconductor memories, and electromechanically addressable devices such as magnetic tapes, disks, and drums were the few technologies from which a computer system designer could build a memory system. A number of different new technologies and devices have been developed that close the "access gap"¹⁴between the two dissimilar technologies mentioned above. These include charge-coupled devices (CCD's),²bubble memories,⁴electron beam addressed memories (EBAM),¹⁷and domain tip propagation (DOT).¹⁶Other technologies like CMOS¹and integrated injection logic (I²L),⁹compete directly with the existing technologies. Table 1 (see p. 46) shows the possibility of a six-level hierarchy and some cost and performance projections for these technologies.