I decided to share a small forgotten piece of code that I wrote back in 2002-2004 in order to port fasm to a custom operating systems working on FAT32 partition. It provides a basic file system access and implements an API exactly as needed by fasm core (the functions: create, open, lseek, read, write, close). It uses many simplifying assumptions - it handles only one disk partition (MBR scheme, there was no GPT back then), and does not support long file names. It also most likely has some bugs, because it was never used much and so it was not thoroughly tested. But perhaps someone might still find it useful.

I have personally used it as a helper tool in some of my closed projects, but I really feel that I should have shared it with you back when I created it, as I feel I did not really make a good use of this code while it could serve as a nice example for OS development. If you use FAT32 partition, then you can easily port fasm to a custom OS with a little driver like this one.

Hi Tomasz,
What is the license?

I put a note in the source that it is a part of flat assembler project, and my intention was that it should be treated as it was under the same license as fasm. But the strict use of such license it is not important to me - I only ask anyone using my code to acknowledge it somewhere in the documentation or comments.

I do not treat this code as something really valuable, it was never really completed even in its basic functionality (note how it uses a variable to track current directory, but does not have a function to change that directory to something other than root, and does not parse paths).