An optical sub assembly for receiving an optical fiber transmission line for coupling to an optical device, to a receptacle for use in such a sub assembly and to a method of manufacture of such a sub assembly. Nitrogen atom content of the films is controlled to within from about 5 to about 25 at. The memory controller is configured to route write data from the first write operation through a plurality of drivers and receivers connected to a plurality of data pins that are capable of connection to one or more memory modules.