EXTERNAL STORAGE DEVICE AND ITS MEMORY ACCESS CONTROL METHOD

PROBLEM TO BE SOLVED: To increase the speed of memory access while performing error detection and correction using a single error correction means in an external storage device that successively accesses sector data. SOLUTION: In the external storage device, the sector data written by a host 2 is stored in a temporary write buffer 7. A microprocessor 8 stores the sector data in a first memory 4 if the sector data stored in the write buffer is odd-numbered, and in a second memory 5 if the data is even-numbered. When the host 2 reads the sector data, a data switch means 11 simultaneously outputs the N-th sector data read from the first memory to a system bus and outputs the (N+1)-th sector data read from the second memory (next sector data to be read by the host computer) to the error correction means. In this way, the time required to detect and correct errors in the (N+1)-th sector data is reduced apparently. COPYRIGHT: (C)2009,JPO&INPIT