Understanding what is epos software boils down to understanding what it does. A POS system process the sale where a transaction takes place. It has been doing this since the time of when the first cash register has been built by IBM in 1973 which were store systems could handle multiple POS registers. The system introduced the primary use of client server technology, peer to peer communication, remote initialization, and backup. In 1974, McDonald's were the first to use microchip controlled cash register systems.