Method and Apparatus for Operating a Computer

A computer system comprising a processor in communication with a memory structure; the processor retrieving and executing executable code stored in the memory structure thereby to process data stored in and retrieved from the memory structure; the memory structure including at least an area designated as an executable application code storage area and a separate area designated as a data storage area; the executable application code storage area switchable by a memory state switch structure between at least a first state and a second state; whereby in the first state the memory in the executable application code storage area is read enabled and write enabled; whereby in the second state the memory in the executable application code storage area is read enabled and write disabled.