In the way of developing a new server (Distributed File System server) on minix3, we thought about implementing some system calls will be used to communicate with the server via the message passing interface minix3 provides.
The problem comes for the system call. After changing the appropriate files, installing a new image and rebooting to the new image, we realized that the command we implemented to call the server using the system call, was not available to 'see' the system call. So when we call:
dfs_ctl(someinteger);
nothing happens at all, as in a normal case it should print some debug messages. Putting it all together, the problem is that the command cannot find the implementation of the system call.
Tip: previously when compiling the command we had a problem : "Undefined _dfs_ctl" which was solved, so i think the system call is mapped as well.