Do there exist any filesystem driver example in C ?
As far as I know this type of sample code is very rare indeed.
If what you're after is an example of how TD64/NSD commands may be used by client code in general, I may have something to share.
A couple of a years ago I wrote a shell command (in 'C', naturally) for the purpose of making image files from my A3000UX hard disk partitions, and uploading them to a local server via TCP. That shell command (called "SendRawDisk") supports TD64/NSD commands, and also includes portable 64 bit integer arithmetic functions for use with compilers which do not support the 'long long int' type (such as SAS/C). It could serve as an example of how this stuff is done in client code. Mind you, it does a bit more than just reading the data off the disk...
You can download the command (with source code) at
http://aminet.net/comm/tcp/SendRawDisk.lha
