EDO: Extended Data Out
In the realm of electronic hardware
refers to a type of DRAM
known as "Extended Data Out".
EDO DRAM is characterised by the way data is presented during memory-reads. Specifically, during a read operation, the output data is latched and therefore persists after the DRAM's column address strobe, (CAS), is de-asserted.
This simple feature speeds up reads of words in the same page of DRAM by allowing the processor to strobe the first address in, de-assert CAS and set up the next read address while the DRAM is fetching data from the first address. This is what distinguishes EDO DRAM from its progenitor: FPM, (or "Fast Page Mode"), DRAM.
As with many technical innovations, EDO's time has all but passed. Five years or so after EDO became mainstream, SDRAM is now de rigeur in the RAM world.