Set default was inherited from dBase, CD and ChDir were added because those commands where used in DOS. You will see the same with a lot of SYS() functions, after some times the 'popular' functions also got a 'userfriendly' name.
>Hi
>If Set Default, CD, ChDir do the same thing why create so many?
>If they are different, than what's the difference?
>Thank you.