The comparative cost of associative memory

The production cost-per-bit of high-speed associative memory, implemented with m.o.s. l.s.i. content addressable memory (c.a.m.) devices (selected from a survey of 20 designs), is compared with that of conventional memory, implemented with currently available m.o.s. l.s.i. random access memory (r.a.m.) devices. For a development cost of about £20k, the cost-perbit of the m.o.s. c.a.m.s is about 5× that of a 1024-bit p-channel m.o.s. dynamic r.a.m. and about 9× that of a 4096-bit n-channel m.o.s. dynamic r.a.m., if plastic dual-in-line packaging is employed. However, for open-chip (beam-lead or flip-chip) assembly the cost-per-bit of the m.o.s. c.a.m.s is less than 2× that of the 1024-bit r.a.m. and less than 3× that of the 4096-bit r.a.m. It is shown that for most associative processing applications the associative memory can provide a cheaper alternative to conventional r.a.m.-based computer systems.