The operating system organises information in a way that allow:
- Quick access
- Economy of storage
- Ease of update &
- Simplicity of maintenance
Also read: functional organisation of the CPU
This order is common among most operating system. The major difference between a folder and a sub folder is no much other than that a sub folder is held inside a folder.
These are storage media or devices connected on computer. They are always allocated labels as in letters from A to Z as an identity. You could review the post on purpose of drivers, drives and plugins to understand farther.
Also read: structure of the harddisk and how it works
Is a named storage location where related files can be stored. It is also known as directory.
A collection of related data given a unique name for ease of retrieval, manipulation and storage. Files have various extensions with each referring to the program it was developed from or on which program it can be run. You can view a detailed description here (examples of file extensions & there respective meaning).