2801	 Storage-Efficient Representation of Decimal Data	 Usually n decimal digits are represented by n bits in computers. Actually two BCD digits can be compressed optimally and reversibly into bits and three digits into bits by a very simple algorithm based on the fixed-length combination of two variable field-length encodings. In over half of the cases the compressed code results from the conventional BCD code by simple removal of redundant bits. A long decimal message can be subdivided into three-digit blocks and separately compressed the result differs from the asymptotic minimum length by only . percent. The hardware requirement is small and the mappings can be done manually. binary-coded decimal digits decimal data storage
