An object of the present invention is to provide a vehicle backward movement assisting apparatus during parking, in which a steering assisting guide display is performed so that a driver can easily comprehend a steering rate and time frame, a steering amount or a backward movement amount in parking a vehicle. It further includes a data interleaver interleaving the RS-coded data packets, a known data generator generating know data symbols, a converter converting the interleaved data packet into symbols, and a symbol processor processing the converted symbols. The results of this analysis may be displayed via a user interface of the host system, andor may be used to automatically take a precautionary action such as transmitting an alert message or changing a mode of operation of the storage subsystem.