call an IOS function from C

Hi ! Where can I found example of IOS system calls from C code.
is it possible to read from the SD without fat.h, but directly with an IOS call?

Check out the libogc source code. Yes, you can read directly from SD using the methods that libfat uses. But libfat reads the data as FAT - ie: interpreting the filesystem, so that you can actually make some sense out of what you're reading in. Reading in raw sector data doesn't make any sense, unless you happen to have a low-level understanding of how to manipulate that data.

I'll check that. Thanks to point the way read syscall read the filesystem.
I don't want to re implement fat.h (I'm not bill gates ;) )