counter is split into two, each counting independently up to 99.
The 1st and 2nd digits count for conditions imposed in bb
The 3rd. and 4th digits count for condition imposed in aa and direct
(b) Span Counter
This makes it possible to count on a part only of the text between start and
It controls two sets of decade switches (0000 - 9999) labelled "start",
"end", on the panel above the printer.
If "start" is set at m , "end" at n , the places counted on from the mth to
(n-1)th inclusive, on the tape from which the start sign is taken.
Note: The position counter continues to work in terms of start signs not in terms
of the beginning of span.
(c) Set Total
A device whereby only scores which exceed, or, alternatively, scores which
do not exceeded; a fixed score, are displayed or printed. The switches are above
the plug panel, viz. a set of decade switches (0000 - 9999) and a three way
54G THE PRINTER
(a) Lost scores
On Robinson stepping is always uniform, so that when scores appear in rapid
succession it is not possible to inhibit stepping till they can be printed and
scores may thus be "lost". Various devices are used to prevent this.
1. The printer is made to print as fast as possible, without spacing, in
fact too fast to print the same figure twice successively. When two or more digits
which are alike occur together, the printer replaces all but the last by arbitrary
letters (actually a,b,c,d,e,f,g for the first seven digits respectively) for
example ab072f39 means 00072339.
2. Two scores can be stored at once (instead of one as on Colossus).
3. The machine is not made to count as fast as it could be.
4. If nevertheless a score is lost, this is shown in two ways.
(i) A light appears below the display (labelled "lost count")
(ii) A cyclometer records the number of lost scores.
The cyclometer can be reset (but only one at a time) by throwing a switch
near the cyclometer up to "meter".
This switch cuts out the printer: unfortunately if it is thrown to normal
during a run it is apt to demoralize the printer and produce rows of dots.