The feasibility of a large-scale microprogrammed computer and some variations and extensions of Wilkes' scheme are examined. A general scheme is discussed to improve flexibility and reduce the number of micro-orders through massive use of the conditions for the next micro-order. A variable-cycle timing system that permits the speed of a synchronized computer to approach that of an asynchronous one is presented. Problems and solutions of input-output operations including time sharing and multiprogramming, and some technical problems, are discussed in detail. A particular scheme of the arithmetic unit included in a micro-programmed control unit is presented.