Storage modules, methods of operating a storage module, and methods of operating a host controlling a storage module

A storage module comprising:

• a dynamic random access memory (DRAM) device configured to communicate with an external device through a first interface and perform a refresh operation in response to a refresh command from the external device;
• a nonvolatile memory device;
• a high-speed buffer memory;
• and
• a controller coupled to the first interface and configured to:
• copy target data from the nonvolatile memory device to the high-speed buffer memory responsive to the external device entering a page fault mode,
• wherein, when the external device is in the page fault mode, the controller is further configured to move the target data copied to the high-speed buffer memory to the DRAM device in response to the refresh command,
• wherein, when the external device is in the page fault mode, the DRAM device is further configured to receive a valid command from the external device after a first refresh reference time elapses from a time point when the refresh command is received from the external device, and, when the external device is not in the page fault mode, the DRAM device is further configured to receive the valid command from the external device after a second refresh reference time elapses from the time point when the refresh command is received from the external device, and
• wherein the first refresh reference time is longer than the second refresh reference time.

A method of operating a host that is configured to control a storage module comprising a dynamic random access memory (DRAM) device and a nonvolatile memory device, the method comprising:

• entering a page fault mode when target data is absent from the DRAM device;
• changing a refresh reference time from a first reference time to a second reference time in response to entering the page fault mode, the second reference time being longer than the first reference time;
• transmitting a refresh command to the storage module;
• and
• providing a valid command to the storage module after the second reference time elapses from a time point when the refresh command is transmitted.