But even apart from the politics of the machine, Alan had come too late to direct its development.
Already the important decision had been taken to adopt, for use as a large, slow, backing store, a rotating magnetic drum such as A.
With digits stored on tracks around the drum to be read off by a head, this was equivalent to providing a large number of slow, cheap, delay lines for the storage of data and instructions not immediately in use.
Another innovation in the design, a modification originally suggested by Newman, was that of the 'B-tube'.
(It was so called because the arithmetic and control tubes were naturally 'A' and 'C' tubes respectively.)
This additional cathode ray tube had the property of modifying the instructions held in the control;
in particular it could be used when working along a sequence of numbers, in such a way that the idea of the 'next' number did not have to be rendered into laborious programming.
As such it was contrary to the general policy that Alan had pursued on the ACE design, that of using instructions rather than hardware as far as possible.