A microprocessor-based system is provided with a non-volatile store (such as a PROM) which stores a bootstrap program, a non-volatile store (such as an EPROM) which stores one or more program overlays, and a programmable volatile store (such as a RAM) which can be written into and read from. When the...http://www.google.fr/patents/US4720812?utm_source=gb-gplus-shareBrevet US4720812 - High speed program store with bootstrap
