File System

A computer is a file storage machine with a math processor and some i/o ports.

The most important part of a computer is the file system.  Without files it has nothing to work with.

There are two kinds of files, software and user data.

Software is the operating system and all the installed programs and their data that are used to produce user data.

User data is all records, graphics, settings, work-product, emails, web pages, and so forth, that must be created or set, which does not come with the software.

Software and data can be replaced if lost.  User data cannot be replaced if lost.