A semiconductor random access memory system for use in a processor system is adapted to operate with a magnetic disc storage device, such as the so-called floppy-disc store. A semiconductor RAM has data input/output terminals and address terminals for writing data into or reading data out of a storage location that is addressed by an address signal supplied to the address terminals. Track and sector address registers are coupled to the processor system for receiving and storing the typical track and sector address signals normally generated in the system. A counter counts timing pulses to produce a changing count signal, which timing pulses are generated by a timing control circuit. An address synthesizer is coupled to the track and sector address registers and also to the counter for synthesizing a RAM address signal from the stored track and sector address signals as well as the count signal and for supplying this RAM address signal to the RAM address terminals to access the RAM storage location which is addressed thereby. Thus, when the processor system generates the typical track and sector address signals normally used with a floppy disc store, such track and sector address signals are used to address a typical semiconductor RAM.