On 28/11/2008 21:41, Chris Elmquist wrote: I don't have a datasheet but I found several equivalences in a Toshiba 1982 databook. MSM37xx designates MOS DRAM, MSM21xx is MOS static RAM, MSM51xx is CMOS SRAM, and MSM27xx is EPROM. I found the more of the same in an NEC databook, but of all the memory databooks I've got, the 1982 Toshiba is the only one listing any MSM37xx devices. OKI MSM3764-xx is an exact equivalent of a 4164, and the 2-digit suffix gives the speed in tens of ns. I'd guess that an MSM3732-20 is 32Kx1, 200ns access time, and likely consists of an MSM3764 with one half disabled or dysfunctional. If so, the 'RS' may signify which half works. -- Pete Peter Turnbull Network Manager University of York