The Cypress CY27H010-35WC is a 1 Mbit (128K x 8) parallel EPROM in a 32-pin CDIP package. It's a non-volatile memory for code storage, firmware updates, and configuration data in legacy systems that use a parallel interface and a through-hole socket. The 35 ns access time means it can keep up with older CISC and 8-bit microcontrollers without wait states.
For a system running a 10 MHz clock (100 ns cycle), this part leaves about 65 ns of margin for address decoding, bus settling, and hold times — plenty of headroom. If you're upgrading a board that originally used a 45 ns or 55 ns EPROM, the 35 ns part drops right in and gives you faster reads, no timing tweaks needed. The parallel interface is straightforward: drive the address lines, strobe /CE and /OE, and data appears on the 8-bit bus.
Package and mounting — socketed field swap
The 32-pin CDIP (Ceramic Dual In-line Package) is through-hole, so it goes into a socket or solders into plated through-holes. Ceramic package means it's hermetic — good for environments where moisture ingress is a concern, but the commercial temp range is the limiter. No lab bench needed.