How was the Linux NTFS Driver written?

Microsoft haven't released any documention about the internals of NTFS, so we had to reverse engineer the filesystem from scratch. The method was roughly:

1. Look at the volume with a hex editor
2. Perform some operation, e.g. create a file
3. Use the hex editor to look for changes
4. Classify and document the changes
5. Repeat steps 1-4 forever

If this sounds like a lot of work, then you probably understand how hard the task has been. We now understand pretty much everything about NTFS and we have documented it for the benefit of others: http://linux-ntfs.sourceforge.net/ntfs/index.html

Actually writing the driver was far simpler than gathering the information.

from http://linux-ntfs.sourceforge.net/info/ntfs.html