This paper presents a new memory hierarchy system using next-generation non-volatile memory devices merging a conventional main memory layer and a disk storage layer into a single memory layer, called a memory-disk integrated system (MDIS). In the MDIS, files are stored in MDIS storage and accessed in place as if they are in conventional DRAM main memory without any duplication between the main memory and secondary storage. The MDIS comprises three components: a virtual accessing adapter (VAA), an array of non-volatile hybrid memory (NVHM), and its associated virtual memory management module. The NVHM can be divided into two spaces - specifically, static and dynamic spaces - to support conventional memory management. Further, the VAA comprises four small buffers that support static and dynamic virtualization according to program execution characteristics. Experimental results show that the read/write load traffics for the proposed MDIS can be reduced by about 73% as compared with the cases of conventional main memory system. In addition, access latency of non-volatile hybrid memory is reduced by 51%.