An electronic system includes a host device and a storage device including a first memory device of a volatile type and a second memory device of a nonvolatile type. The first memory device is accessed by the host device through a memory-mapped input-output interface and the second memory device is accessed by the host device through a block accessible interface. The storage device provides a virtual memory region to the host device such that a host-dedicated memory region having a first size included in the first memory device is mapped to the virtual memory region having a second size larger than the first size.