How to implement a very simple filesystem?

Question

I am wondering how the OS is reading/writing to the hard drive.
I would like as an exercise to implement a simple filesystem with no directories that can read and write file

Answer 1

Take a look at FUSE: http://fuse.sourceforge.net/

This will allow you to write a filesystem without having to actually write a device driver. From there, I'd start with a single file. Basically create a file that's (for example) 100MB in length, then write your routines to read and write from that file.

Once you're happy with the results, then you can look into writing a device driver, and making your driver run against a physical disk.

The nice thing is you can use almost any language with FUSE, not just C/C++.