Function  3Ch   Create A File (CREAT) 
		Create a file with handle  
entry   AH      3Ch 
	CX      attributes for file 
		00h     normal 
		01h     read only 
		02h     hidden 
		03h     system 
	DS:DX   address of ASCIIZ filename string 
return  flag CF 0       successful creation 
		1       error 
	AX      16 bit file handle 
		or error code  (3, 4, 5) 
note 1) The ASCIIZ string may contain drive and subdirectory. 
     2) Drive may be any valid drive (not nescessarily current drive) 
     3) If the volume label or subdirectory bits are set in CX, they are ignored 
     4) The file is opened in read/write mode 
     5) If the file does not exist, it is created. If one of the same name  
	exists, it is truncated to a length of 0. 
     6) Good practice is to attempt to open a file with fn 3Dh and jump to an 
	error routine if successful, create file if 3Dh fails. That way an 
	existing file will not be truncated and overwritten.