Abstract: Disclosed is a communication system that transmits data through a transmission path between a transmission side apparatus and a reception side apparatus, wherein the transmission side apparatus comprises a coding apparatus that creates redundantly-coded data from original data; a transmitting apparatus that sends the coded data coded by the coding unit to the transmission path; and a coding rate determining apparatus that sets and controls a coding rate in the coding unit, wherein the reception side apparatus comprises a receiving apparatus that receives the coded data sent through the transmission path; a decoding apparatus that decodes the original data from the coded data received; and a loss rate estimating apparatus that measures the loss rate on the path of the coded data sent, and wherein the coding rate determining apparatus of the transmission side apparatus varies and controls the coding rate in the coding apparatus based on the loss rate obtained.

Abstract: The data dividing unit divides data into n pieces. An encoding unit generates m pieces of encoded data composed of a set of a bitmap matrix specifying a plurality pieces of divided data for obtaining exclusive OR (XOR) and exclusive OR data including exclusive OR of the plurality pieces of divided data specified by the bitmap matrix, wherein m is equal to or more than a dividing number n and according to redundancy. A distributed saving unit distributes and saves the m pieces of encoded data to and in storage devices at two or more locations and m or less locations. A decoding unit restores the original data by retrieving restorable k or more pieces of the encoded data among the distributed and saved m pieces of encoded data and subjecting the bitmap matrix of the retrieved encoded data to conversion into a unit matrix.

Abstract: An IP-data transmitting apparatus performs an error correction coding by classifying data into a layer indicative of the priority order of the data based on importance and vulnerability of information included in the data, and combining a plurality of data components into combination patterns. The number of the combination patterns is specified with respect to each layer with predetermined priority order.

Abstract: A storage apparatus composed of a plurality of magnetic disk devices are provided. An encoding unit generates, after dividing original data, a plurality pieces of encoded data equal to or more than the number of division by use of a code of which redundancy is variable. A redundancy control unit varies the redundancy in the encoding unit in accordance with the importance of the original data. A distribution processing unit distributes and stores the plurality of encoded data to and in the plurality of magnetic disk devices. A decoding unit retrieves the encoded data corresponding to, at least, the division number of the original data from the magnetic disk devices so as to decode the original data.

Abstract: A backup system is comprised of a main storage for storing original data and a plurality of local storages for distributing and storing the data. An encoding unit of the main storage server generates, after dividing the original data, a plurality of encoded data that is equal to or more than the dividing number by use of a code of which redundancy is variable. A distribution processing unit distributes the plurality of encoded data to the plurality of local storages, and causes the data to be stored therein. A restoring unit retrieves the encoded data corresponding to at least the division number of the original data from the local storages, and restores the original data. A redundancy control unit varies the redundancy in the encoding unit such that, the higher the importance of the data, the larger the redundancy. Furthermore, a distribution processing unit determines the distribution number such that the higher the reliability of the local storages, the more the number.

Abstract: A wafer detecting device usable with a carrier has a plurality of wafer carrying portions disposed in stories for carrying wafers thereon. The device comprises a light emitting portion for emitting a light beams so that it passes through the carrier from one side thereof to the other side thereof and in a direction substantially parallel to a plane in which a wafer is carried on a wafer carrying portion of the carrier. A light receiving portion is disposed at the other side of the carrier for detecting presence/absence of the light passed through the carrier.