The present technology includes a controller including an allocation manager configured to determine whether a host identification (ID) output from a host is an allocable ID, an address manager configured to perform an allocation operation using the host ID to select logical blocks corresponding to the host ID when the host ID is received from the allocation manager, and output an address of the logical blocks as an allocation address, and a map table component configured to store a map table in which logical block addresses and physical block addresses are respectively mapped, select a logical block address corresponding to the allocation address, and output the physical block address mapped to the selected logical block address, a memory system including the controller, and a method of operating the memory system.