Abstract: Disclosed is an expanded foamed bead of a rubber-modified styrene polymer, comprising a plurality of closed cells defined by cell walls which constitute a matrix for the bead, wherein each of the cell walls comprises two surfaces separated by a distance equal to the thickness of the cell wall.

Abstract: A system for executing an updating or restoring method for stored data groups in a nonvolatile storage device provides a data storage portion having a first data domain and a second data domain which make up one pair and are an object to be updated. An information management table manages a pointer and a current pointer corresponding to each of the data domains. A pointer updating log management table temporarily stores the current pointer when the data domain is updated. A data updating processor updates data by temporarily storing the current pointer, by updating the first or the second data domain, and by transferring the current pointer, when data is updated. A data restoring processor restores information in the data domain before updating by restoring the contents of the current pointer, when data is restored after interruption of the updating operation. Thus, high speed data updating and restoring can be carried out.