MAIN STORAGE DEVICE ACCESS SYSTEM

PURPOSE:To shorten the time required for the information access of a central processing unit (CPU) by providing a main storage device with plural storage means having respectively different speeds, connecting a cache memory to the main storage device and storing respective information in respective storage means in the main storage device in accordance with access characteristics. CONSTITUTION:This main storage access system is provided with the CPU 1, the cache memory 2, the main storage device 3, and an auxiliary storage device 5 to be accessed by an auxiliary storage device access means 4 to aid the device 3 and the device 3 includes the storage means 31-l to 31-n having respectively different speeds of n steps from a high speed up to a low speed. Information having high access frequency and small locality and comparatively dispersed is transferred from the high speed side storage means 31-l to a certain storage means 31-(i-l). Consequently, the time required for the CPU 1 to access information is shortened.