The Newmanry History
Part of the General Report on Tunny(1945)
Codes and Ciphers
52 Page 328
52. DEVELOPMENT OF ROBINSON AND COLOSSUS
Some of the paragraphs in this chapter will not be fully intelligible
without reference to the two chapters which follow: 53, 54.
A brief description of the two machines has already been given [15(b)]. The
essential difference between them is that on Robinson all streams of letters are
on tapes. On Colossus only Z is on a tape, the wheels being set up electrically.
(b) Heath Robinson.
In the experimental stages of Tunny-breaking, though other forms of machine
were considered, it was inevitable that one using Robinson principles should be
(a) it is easy to make.
(b) it can be adapted to any wheel length by preparing
The original Heath Robinson was effective, despite what now seem intolerable
(i) There was at first no printer: the operators
(two in number) had to write down the fleeting
figures on display: this was a fruitful source
(ii) The distance between the gate where the tape
was scanned and the sprocket-wheel which drove
it was six inches, so that the stretching of
tapes alone was sufficient to put tapes out of
(iii) The position counter recorded, not the relative
position of the two tapes, but the number of
revolutions completed: from this the relative
position can be found but with great risk of
(iv) Heath Robinson would not tolerate long stretches
of dots or of crosses, so that elaborate tapes,
with additional opportunities for making mistake.
had to be devised to avoid this.
(v) The minimum text length was 2000. If it was
less, rubbish had to be inserted in such a way
that it was not counted.
(vi) There was no spanning.
(vii) The forms of impossible conditions were severely
(viii)The counters were only partly electronic.
(ix) At first Heath Robinson was unable to obtain
results, even if not itself at fault, because
the tapes, not being subject to a proper system,
of checks, were incorrectly made.
As a direct result of experience with Heath Robinson all the improvements
needed to remedy these defects (except spanning, whose value was overlooked till
later) were incorporated by stages in Old Robinson and Super Robinson, and
incorporated at the outset in Colossus.
(c) Old Robinson (Figs 58 I,II)
The Old Robinson, which followed Heath Robinson, had a special Gifford
printer, which should have been far superior to the ordinary typewriter, for it
printed all eight digits at once: in fact it caused endless trouble, and its
records were barely