When sequential processing is needed a table that performs an order-preserving transformation on keys can be used. We present methodologies for constructing such key transforms, and illustrate them for some real-life key sets. Storage requirements for the table needed to carry out the transformation are less than those needed for the indices. The authors propose such an algorithm for alphabetic keys.
Careful work is necessary to distribute the table correctly, as the letter usage is far from linear.
The proposed algorithm allows for this. As might be expected, there are problems not only at file establishment time, but also with growth. The authors propose a solution for this problem. As a research study, this paper is quite complete. The reviewer's only criticism of the proposed technique is mentioned also by the authors.