was ordered separately by the Runs Registrar the Duty Officer being consulted if
necessary. At this time the D.O. was responsible for all work on messages tried
in the Newmanry and it was in Ops. that the psis were first set by hand in
November, 1943. After this there was an almost immediate change of policy, Room
41 took over the job of psi-setting by hand, and Robinsons were used to set all
five chis on as many messages as possible. This policy remained unchanged for
almost a year though spasmodic efforts at machine psi and motor-setting were made.
The Newmanry moved to Block F late in November, 1943: the first 'Heath'
Robinson was replaced by 2 production models and others came later. Colossus 1
came in February 1944 and runs on the new machine took so short a time that it was
necessary to decide policy on the spot and a Colossus man was appointed.
Colossi soon replaced Robinsons for setting purposes and the duties of the Runs
Registrar were increasingly confined to issuing tapes to machines in the right
order and seeing that they did not stay there for too long. By the end or August
no Robinsons and up to 4 Colossi were used for setting.
As the number of Colossi increased Wren operators were left more and more on
their own. A Colossus man was always available for consultation, and the D.O. kept
a check on the accuracy of all Colossus work. From July, 1944 onwards the D.O.
saw every Colossus dossier as it returned to Ops. and took over the responsibility
for abandoning messages and ordering de-chis.
This had previously been done by the Colossus man.
By November, 1944 many new Wrens were working Colossi on their own and
considerable time was being wasted. Either too many runs were done, or so few
that further runs had to be ordered by the D.O. For this reason the runs normally
done were standardised, the 'trees' or runs schedules varying according to the
type of language and limitation expected. Departures from
schedule were only made in consultation with the Colossus man. The new 'rules' had
a remarkably good effect and were interpreted in an increasingly liberal way.
In the Summer and Autumn of 1944 there was so much chi- setting to do that
psi runs were not done. But in November, when there were 6 Colossi, Motor and Psi
runs were done more often, and after December 25th it became a routine to do them
on low dottage days. From March 5th, 1945, a new policy of setting
motors and psis on Colossus in every possible case was adopted, exceptions only
occurring on days of high dottage, or days for which motor patterns were not yet
broken. Wrens soon picked up the technique and were able to do motor and psi runs
on their own. The machine resources in 1945 are given in part 5.
The D.O. was responsible for knowing what wheel-breaking was in progress,
whether on significant rectangles, key, or crib. As soon as it appeared likely
that a day would come out, the D.O. (in consultation with the W.M. or head of Room
41) asked the C.O. to order the traffic from Knockholt on C-procedure,
and recommended whatever priority and procedure seemed to fit the general priority
of the link, date, estimated dottage, and estimated time of completion of the
wheels. The priority of the wheel day was assigned by the morning meeting if it
was being worked on when this took place : otherwise the priority had to be
decided from the general priority list or in consultation with Hut 3 (See 33A).
(d) Further Runs
We referred in 37(a) to 'Further Runs'. These were of 5 main types.