EXTERNAL STORAGE DEVICE AND MEMORY ACCESS CONTROL METHOD

PROBLEM TO BE SOLVED: To speed up memory access while detecting and correcting an error by a single error correcting means in an external storage device which continuously accesses sector data. SOLUTION: Sector data written by a host 2 is temporarily stored in a write buffer 7. A microprocessor 8 stores the data in a first memory 4 when the sector data stored in the write buffer is odd-numbered sector data and stores it in a second memory 5 when it is even-numbered sector data. When the host 2 reads the sector data, the N-th sector data read from the first memory is output to a system bus, in a data switching means 11, and the (N+1)-th sector data read from the second memory (the sector data to be read next by the host computer) is output to an error correction means simultaneously. Thus, the time required for error detection and error correction for the (N+1)-th sector data is apparently reduced. COPYRIGHT: (C)2010,JPO&INPIT