POSIX environments provide at least two ways of accessing files. There's the standard system calls `open()`, `read()`, `write()`, and friends, but there's also the option of using `mmap()` to map the file into virtual memory.When is it preferable to use one over the other? What're their individual advantages that merit including two interfaces?
mmap() allows for multiple processes to access the same physical data. This can be useful when you want to communicate between processes or need to limit space so that data is not copied between processes. For example, you can use one process to write data and use another to read the written data to communicate between these processes.
