Linear sum codes (LSCs) form a class of error control codes designed to provide on-chip error correction to semiconductor random access memories (RAMs). They use the natural addressing scheme found on RAMs to form and access codewords with a minimum of overhead. The authors formally define linear sum codes and examine some of their characteristics. Specifically, they examine their minimum distance characteristics, their error correcting capabilities, and the complexity involved in their implementation. In addition, detailed consideration is given to an easily implemented class of single-, double-, and triple-error correcting LSCs. >