A programmable policy module allows a user to configure specific policy elements available from a software application, in order to meet a particular assurance level. Provided between the substrate and the semiconductor chip is a spacer, which is coupled mechanically to the substrate andor the semiconductor chip. The steering foils have respective longitudinal steering foil axes being oriented in a direction substantially perpendicular to a longitudinal axis of the float body and so as to be substantially perpendicular to a sea surface when in use, the elongated steering foils having respective first and second chord axes. If the validators correspond, then the received relative data set is applicable to the full data set stored at the database, and the relative data set may be processed as a change set. These file attributes can include Unix perms, ownership and timestamp information, and link information. Instead, if throughput is insufficient to send an encoded group of pixels, the encoder leaves the check value for that group unchanged and sends a command instructing the decoder not to change those pixels.