INT 21 - DOS 1+ - READ RANDOM RECORD FROM FCB FILE

	AH = 21h
	DS:DX -> opened FCB (see #01345)
Return: AL = status
	    00h successful
	    01h end of file, no data read
	    02h segment wrap in DTA, no data read
	    03h end of file, partial record read
	Disk Tranfer Area filled with record read from file
Notes:	the record is read from the current file position as specified by the
	  random record and record size fields of the FCB
	the file position is not updated after reading the record
	if a partial record is read, it is zero-padded to the full size
	not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=14h,AH=22h,AH=27h,AH=3Fh"DOS"