Why we need files

We have three essential requirements for long-term information storage: It must be possible to store a very large amount of information. The information must survive the termination of the process using it. Multiple processes must be able to access the information at once. Just a few of the questions that quickly arise are: How do you find information ? How do you keep one user from reading another user's data ? How do you know which blocks are free ? As we saw how the operating system abstracted away the concept of the processor to create the abstraction of a process and how it abstracted away the concept of physical memory to offer processes address spaces, we can solve this problem with a new abstraction: the file.Files are logical units of information created by processes.File system is the part of operating system dealing with files.