INT 7F - Alloy MW386 - GET USER NAME                                            
	AH = A0h
	DL = user number (FFh = caller)
	DH = machine number for user
	ES:DI -> 17-byte buffer for ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. user name
Return: CF set if invalid user number
SeeAlso: AH=03h,AH=A1h