Consider the case where you need different parts of the same file from many processes concurrently (e.g. a lookup table). It may fit into memory but not into me

Consider the case where you need different parts of the same file from many processes concurrently (e.g. a lookup table). It may fit into memory but not into memory N times (yes you can use shared memory etc.). Most files are write once read many times so no need for synchronization....