APPENDIX 1
HOLLERITH TIMING
In order to link the operation of the DEUCE with the Hollerith Read and Punch, it is useful to know the time in Major Cycles between various operations on the two Machines. A chart of these is attached. The column referring to the Reader will be explained, that for the Punch being very similar.
(a) From the time of the Hollerith one-shot, Source 0 continues to give the current row for a period of 2 Major Cycles. From 6 Major Cycles onwards Source 0 gives zeros, representing the space between rows.
(b) Not less than 15 and not more than 21 Major Cycles elapse between successive one-shots from the same cards. Thus, computations which take place between rows should not last more than 15 Major Cycles if one-shots are not to be missed.
(c) When cards are following each other at maximum speed, the first one- shot of one card follows the last one-shot of the previous card after an interval of not less than 80 and not more than 100 Major Cycles. Computations which take place between cards should not last more than 80 Major Cycles if first one-shots on each card are not to be missed.
(d) Between the 11th one-shot and the beginning of TIL there is a period of at least 11 Major Cycles. From the beginning of TIL to the 12th one-shot there are not less than 2 and not more than 7 Major Cycles. After the 12th one-shot TIL lasts for not less than 18 and not more than 23 Major Cycles. Also, after a P54 on the 12th row, or 9-24X using the 12th row stopper, TIL will certainly be off after 23 Major Cycles. For continuous reading, the first one-shot of the next card is at least 57 Major Cycles after the end of TIL. Source 0 does not revert to the I.D. between cards, provided cards are running contin- uously. Otherwise, Source 0 reverts to the ID lamps within 13 Major Cycles after the 12th one-shot.
(e) When the Read has been idle, there is a period of at least 130 Major Cycles between calling for a Read ("12-24") and the arrival of the first one-shot. (f) When the reader is cleared by a P34 on the last row of a card it may (g) be recalled immediately by the instruction 12-24 (using the single- shot from the last row if desired). If however the reader is cleared, (either by a P34 or by an instruction 9-24) before the last row of a card it should not be recalled within 2 Major Cycles, or further rows of the same card will be read as if the reader had not been cleared. (This means that single-shots and the TIL signal will not be inhibited). (h) If the reader is cleared within 40 Major Cycles after the S.S. from the last row of a card, no further cards will be fed. If the reader is cleared between 40 and 70 Major Cycles after the S.S. from the last row of a card, a further card may be fed, but will not be read and will give a 'MISSED CARD' alarm. If the reader is cleared more than 70 Major Cycles after the S.S. from the last row of a card, but before the first S.S. of the next card, a further card will be fed, and not read, without giving a MISSED CARD' alarm. (j) In order to inhibit the S.S. from the subsequent row of a card, reader or punch must be cleared within 13 and 35 Major Cycles respectively of the stop instruction for a given row. (k) If a transfer to destination 29 is made more than 20 Major Cycles after the stop instruction for arty row other than the last, the word sent will be successfully punched on the next row, unless an instruction 8-24 precedes the time of the next row. (l) This is similar to a 'MISSED CARD' on the Reader. If the punch is not cleared within 20 Major Cycles of the last row of a card, another card will pass through the punch. This card will be blank in the DEUCE field but will carry punching in the Job and card numbering sections. (m) If a programme finishes with the punch and then uses D29 for the O.S. lights there is a possibility that the first transfer to D29 after the punch is cleared will punch the next row of the card. This will not occur if the punch is cleared within 24 Major Cycles from the last row on which punching is required.
NS-y-16/5-56
APPENDIX 1 CONT'D

HOLLERITH TIMING TABLE

Event from which time is Time
Requirement after
measured.
Reader
Punch
this time.
a Stop instruction for any 2 4 Successful read or punch.
  row of card.
6
-
Read zeros.
b Stop instruction for 15 38 Catch S.S. for next row.
  any of first 11 rows.
21
46
Miss S.S. for next row.
c Stop instruction for 12th row. 80 116 Catch 1st S.S. of next card
      when running continuously.
  100 135 Miss 1st S.S. of next card
 
 
 
when running continuously.
d Stop instruction for 11th row. 11 33 TIL not yet on.
  Start TIL. 2 2 Catch 12th S.S.
  7 9 Miss 12th S.S.
  Stop instruction for 12th row. 18 35 TIL not yet off.
  23 50 TIL off.
  23 - TIL off after P34 on 12th row.
  23 30 TIL off after 9-24X on 12th row.
 Read cleared by P34 13 - I.D. switches can be used.
 or 9-24X on any row.      
 End of TIL. 57 75 Catch 1st S.S. of next card
 
 
 
when running continuously.
e Call read or Punch when machine 130 180 Catch 1st S.S. of card.
 has stopped (or re-call at least      
 1 second after end of TIL).
 
 
 
f Read cleared by P34 on any row.
0
-
Recall read by 12-24.
g Clear READ or PUNCH by 9-24
2
2
Not read or punch same card on recalling.
h Stop instruction for 12th 40 - Clear READ and not pass
  row of card.     extra card through reader.
  70 - Clear READ and pass extra card through
 
 
 
reader without giving 'MISSED CARD' alarm.
j Stop instruction for any 13 35 Clear READ or PUNCH by 9-24
  row of a card.
 
 
and not get next S.S.
k Stop instruction for any row of card.
-
20
Successful punch on following row.
l S.S. on last row of card. - 20 Clear PUNCH and not pass
 
 
 
extra card through punch.
m Stop instruction for any - 24 Clear PUNCH and not punch
      on next row of card.

NS-y-16/5-56