Abstract: A DC backup power supply system having a battery a charge-discharge circuit for charging and discharging a power between the battery and a DC line and a control circuit for controlling the charge-discharge circuit, wherein the battery has a number of battery cells and cylindrical portions of the battery cells are laid on an approximately horizontal plane.

Abstract: A method of data compression for recording data on a recording medium such as a magentic tape, a method of data restoration for data which has been compressed for recording, and an apparatus of data compression and restoration prescribe the data to be compressed based on type or value and encode the compression object data, thereby reducing the number of bits necessary to indicate the compression object data. Compression is implemented only for consecutive data fewer in number of repeating consecutive bytes than a certain number, thereby reducing the number of bits necessary to indicate the number of bytes of the consecutive data. A compression mark indicative of compression is appended to the compressed data, consisting of data made by encoding the compression object consecutive data and data indicating the number of bytes of the data, either at the front or rear of the compressed data, whereby an input data string can be compressed drastically and compressed data, even including errors, can be restored.