Basic Concepts for Data

Every OS-managed data item is a file
Thus, peripherals are files
Directory are files
Communication channels are files   

The Unix file can be considered the basic data class
The methods are open, close, read, write
The subclasses are regular files, device, directories...

The file is nothing more than an array of bytes
The name is irrelevant to the OS, just a convention
The text encoding is irrelevant to the OS too

Most information is stored as plain text
Redundancy helps disaster recovery
People can do diagnostics by simple inspection
We avoid the need for special format-specific tools