Mappping a file or a portion of file to process virtual address space enables the process to efficiently read / write disk files. This essentially allows the process to take advantage of underlying OS page replacement strategies while reading / writing file contents i.e., the program performs IO reads /writes and the underlying OS does the job of loading /unloading (commiting if updates are there) transperently. I would like to understand the exact benefits of memory mapped io concept. Can any mind through some light on this.