Two level indexing method for accessing data blocks having first pointer to single location containing second pointers to the data blocks

摘要

Mass data is managed as data files in a mass data storage device. Each data file is formed or plural data blocks. Upon editing of a data file, the data content of each data block forming the file is examined. If the data content of a data block is less than a predetermined value, data from one or more adjacent data blocks is extracted and placed in the one data block so that the data content thereof will be at least the predetermined constant value. In this manner, the data content of blocks forming a file is maintained at or above a predetermined level.