# Proposed Electronic Calculator/Chapter 10

​10. Time-table, Cost, Nature of Work, Etc.
The work to be done in connection with the machine consists of the following parts:
(1) Development and production of delay lines.
(2) Development and production of other forms of storage.
(3) Design of valve-elements.
(4) Final schematic circuit design of LC and CA.
(5) Production of the electronic part, i.e. LC and CA.
(6) Making up of instruction tables.
(7) External organs.
(8) Building, power supply cables, etc.
(1) Delay lines have been developed for R.D.F. purposes to a degree considerably beyond our requirements in many respects. Designs are available to us, and one such is well suited to mass production. An estimate of £20 per delay line would seem quite high enough.
(2) The present report has only considered the forms of storage which are almost immediately available. It must be recognized however that other forms of storage are possible, and have important advantages over the delay line type. We should be wise to occupy time which falls free due to any kind of hold-up by researching into these possibilities. As soon as any really hopeful scheme emerges some more systematic arrangement must be made.
​We must be ready to make a change over from one kind of storage to another, or to use two kinds at once. The possibility of developing a new and better type of storage is a very real one, but is too uncertain, especially as regards time, for us to wait for it; we must make a start with delay lines.
(3) Work on valve element design might occupy four months or more. In view of the fact that some more work needs to be done on schematic circuits such a delay will be tolerable, but it would be as well to start at the earliest possible moment.
(4) Although complete and workable circuits for LC and CA have been described in this report these represent only one of a considerable number of alternatives. It would be advisable to investigate some of these before making a final decision on the circuits. Too much time should not however be spent on this. We shall learn much more quickly how we want to modify the circuits by actually using the machine. Moreover if the electronic part is made of standard units our decisions will not be irrevocable. We should merely have to connect the units up differently if we wanted to try out a new type of LC and CA.
(5) In view of the comparatively small number of valves involved the actual production of LC and CA would not take long; six months would be a generous estimate.
(6) Instruction tables will have to be made up by mathematicians with computing experience and perhaps a certain puzzle-solving ability. There will probably be a great deal of work of this kind to be done, for every known process has got to be translated into instruction table form at some stage. This work will go on whilst the machine is being built, in order to avoid some of the delay between the delivery of the machine and the production of results. Delay there must be, due to the virtually inevitable snags, for up to a point it is better to let the snags be there than to spend such time in design that there are none (how many decades would this course take?). This process of constructing instruction tables should be very fascinating. There need be no real danger of it ever becoming a drudge, for any processes that are quite mechanical may be turned over to the machine itself.
The earlier stages of the making of instruction tables will have serious repercussions on the design of LC and CA. Work on instruction tables will therefore start almost immediately.
(7) Very little need be done about the external organs. They will be essentially standard Hollerith equipment with special mounting.
(8) It is difficult to make suggestions about buildings owing to the great likelihood of the whole scheme expanding greatly in scope. There have been many possibilities that could helpfully have been incorporated, but which have been omitted owing to the necessity of drawing a line somewhere. In a few years time however, when the machine has proved its worth, we shall certainly want to expand and include these other facilities, or more probably to include better ideas which will have been suggested in the working of the first model. This suggests that whatever size of building is decided on we should leave room for building-on to it. The immediate requirements are:
Room for 200 delay lines. These each require about 6 inches of wall space if they are to be individually accessible, and if this is partly provided by cubicle construction 300 square feet is probably a minimum. To this we might add another 100 square feet for the temperature correction arrangements.
​Space for LC and CA. This is difficult to estimate, but 5 eight foot racks might be a reasonable guess and would require another 200 square feet or more. In the same room we would put the input and output organs which might occupy 40 square feet. We should also provide another 100 square feet for operators tables, etc. 400 square feet would not be unreasonable for this room.
Card storage room. We would probably keep a stock of about 100,000 cards, a very insignificant number by normal Hollerith standards. 200 square feet would be quite adequate.
Maintenance workshop. We would do well to be liberal here. 400 square feet.
This total of 1400 square feet does not allow for the planning of operations, which would probably be done in an office building elsewhere, nor for the processing of Hollerith cards which will probably be done on machinery already available to us.
Cost. It appears that the cost of the equipment will not be very great. An estimate of £20 per delay line would be liberal, so that 200 of these would cost us £4000. The value equipment at £5 per inch of rack space might total £5000. The power supply might cost £200. The Hollerith equipment would be hired, which would be advantageous because of the danger of it going out of date. The capital cost of such Hollerith equipment even if bought would not exceed £2000. With this included the total is £11,200.