EXTERNAL STORAGE SYSTEM USING SEMICONDUCTOR MEMORY AND CONTROL METHOD THEREOF

摘要

PURPOSE: To make it possible to perform reading out and writing of data with a host CPU, to process at a speed higher than the speed of the conventional magnetic disks and to make the entire memory usable effectively over a long period of time without allowing only the specific sector to be frequently written and erased. CONSTITUTION: An address control system which imparts flexibility to the address relation between the host CPU and an external memory device and prevents the physically address of a semiconductor memory is not one-sidedly determined by the logical address possessed by the command of the host CPU is introduced. A command processing section 34 prepares memory blocks and sectors for writing or erasing and copying at all times preparatory to the command processing of the host CPU and records and holds the corresponding relation of the physical addresses of the selected memory block 32i or sectors and the commands of the host CPU on an address conversion table 36. The conditions of the memory blocks and sectors are recorded on a management table 35 and are utilized for control of processing, such as writing, erasing and copying preparatory to or in response with the commands of the host CPU.