The project handout failed to list the expected return codes for various system calls. Here is the set of return codes for the new system calls for project #4.

Call		Error Return		Normal Return
Mount		-1			0
Delete		-1			0
Open		-1			new file descriptor number
Read    	-1			number of bytes read	
Write		-1			number of bytes written
Seek		-1			0
Stat		-1			0
Close		-1			0
CreateDirectory	-1			0
Format		-1			0