Memory mapping is a process or command in computer programming that requests that files, code, or objects be brought into system memory. It allows files or data to be processed temporarily as main memory by a central processing unit. Memory mapping I/O (input/output) uses an external device, which connects to a computer system so that the computer’s CPU can access the data within the device.
The mmap() system call in Unix, Linux, and other programs (such as C programming language) allows a program to create a new address in which it can process files or objects. Memory mapping requests that files, code, or objects be brought into a different address (in this case, system memory). The operating system, or kernel in Linux, must find or approve the new address. Once the new address has been mapped, mmap() uses the length of bytes to map the data.
The munmap() command, or system call, unmaps or terminates the session when the computer has finished processing the data in memory.