Integrated circuit memory devices with enhanced buffer memory utilization during read and write operations and methods of operating same

A storage device comprising:

• a nonvolatile memory;
• and
• a controller configured to write data to the nonvolatile memory or read data from the nonvolatile memory,
• wherein the controller comprises:
• a processor configured to include a central processing unit (CPU) or a micro-processor, and control overall operations of the controller;
• a host interface between a host and the controller;
• an NVM interface configured to exchange data between the controller and the nonvolatile memory;
• a DRAM controller for controlling a DRAM buffer provided outside the controller and nonvolatile memory;
• a SRAM buffer configured to buffer write data to be written on the nonvolatile memory or read data read from the nonvolatile memory;
• an ECC module configured to check and correct errors in the write data or the read data buffered in the SRAM buffer;
• a monitoring module configured to monitor the number of error bits generated in the SRAM buffer based on an error corrected by the ECC module;
• and
• a buffer manager configured to compare the number of error bits received from the monitoring module to a threshold number and determine the SRAM buffer or the DRAM buffer, as a buffer memory for the write data or the read data based on a comparison result.