Memory system, operating method thereof and computing system for classifying data according to read and write counts and storing the classified data in a plurality of types of memory devices

An operating method of a memory system including a plurality of memory devices, wherein the plurality of memory devices includes a first memory device and a second memory device, and a controller that controls each of the plurality of memory devices, the method comprising:

• determining a R/W ratio—a ratio of a number of read operations to a number of write operations of target data;
• comparing the R/W ratio with a first threshold corresponding to the first memory device;
• selecting the first memory device for storing the target data when the R/W ratio is greater than equal to the first threshold;
• and
• storing the target data in the first memory device.