Hybrid memory device for storing write data based on attribution of data stored therein

In a memory system including a control unit and a hybrid memory device, the hybrid memory device including a memory controller, a first memory operating according to a first speed and a second memory operating according to a second speed slower than the first speed of the first memory and providing greater data storage capacity than the first memory, a method of re-allocating memory space in the first memory during execution of a write operation comprises:

• referencing an attribute information table listing respectively assigned group states for first data, second data and third data stored in the first memory, wherein the first data is assigned a first priority group state among the group states, the second data is assigned a second priority group state among the group states having a priority lower than that of the first priority group state, and the third data is assigned a third priority group state among the group states having a priority lower than that of the second priority group state;
• in response to a received write data request including fourth data, determining whether sufficient free space exists in the first memory to store the fourth data;
• in response to determining that sufficient free space exists in the first memory to store the fourth data, storing the fourth data in the first memory;
• in response to determining that sufficient free space does not exist in the first memory to store the fourth data, re-allocating memory space in the first memory by overwriting the third data with at least a portion of the fourth data;
• and
• changing, in response to completing a process executed upon previous write data written into the first memory, attribution information assigned to the previous write data to reflect that space storing the previous write data within the first memory is free space that is available to be overwritten without copying the previous write data from the first memory to the second memory.