Essence of MySQL

What is the essence of MySQL? If you have to break down MySQL to its skeletal framework, what will you be left with?

MySQL is just made up of files (the extensions with MYI, frm, MYD are just extensions of FILES). I'm being simplistic here... and you can argue that all databases are just made of files. But let me give a couple of examples.

1. When you 'query' the database -- performing select, insert or update... what are you doing? Reading and writing to the MySQL files.

2. When you try to do performance tuning? What are you doing? You are improving how fast you are able to 'read and write' to the MySQL files.

3. When you want to do replication? What are you doing? You are just copying one data from one file to another.

4. When you want to do backup? What are you doing? You are just copying files (making sure that they are not currently being written) to another file.

So, what is the essence of MySQL again?