Why we need files

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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.