| 摘要 |
An information processing system comprises a main memory operative to store data, and a control circuit operative to access the main memory for data. The main memory includes a nonvolatile semiconductor memory device containing electrically erasable programmable nonvolatile memory cells each using a variable resistor, and a DRAM arranged as a cache memory between the control circuit and the nonvolatile semiconductor memory device. The nonvolatile semiconductor memory device has a refresh mode of rewriting stored data. The control circuit activates the nonvolatile semiconductor memory device in said refresh mode based on the number of accesses to the nonvolatile semiconductor memory device. |
