Punch card mixer

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A punched card mixer (English: punched card collator or punch card collator ) is an electromechanical machine for processing punched cards . The first use is documented in 1937 with the American Social Security Board .

The punch card mixer is used to set various functions on u. U. to carry out pre-sorted stacks of punched cards using a punched card sorter, for example mixing one pile into another or “pulling” corresponding punched cards.

With the transition from punched card technology to electronic data processing since the 1960s, punched card mixers were replaced by appropriate file operations (sorting, mixing, group change processing ).

Mechanical construction

A punch card mixer consists of the following parts:

  • two input compartments for stacks of punched cards: the primary card feeder and the second card feeder. The primary card feeder has two scanning stations, the secondary one.
  • Motors, rubber rollers and conveyor belts that move the punch cards
  • Solenoid-operated flaps to control the path of the punch cards,
  • four or five output bins
  • A special compartment is the mixed storage compartment, which can be loaded from both input compartments.
  • Similar to the tabulating machine, a patch panel with which the mixer can be programmed via wire connections via relays.

programming

Outline sketch of punch card shuffling

The data of two punch cards in one scanning station each are compared. Depending on the result of this comparison (smaller, equal, larger), the path of a punch card into one of the storage compartments is controlled.

Functions

Both stacks of punched cards are processed one after the other (the card flow is - as with practically all punched card devices - not reversible), so a basic requirement for correct function is the presence of appropriately pre-sorted card stacks. The sorting sequence is achieved either by shuffling the stacks of cards only with the punch card mixer (ie not by the error-prone "manual insertion"), or by presorting the stacks of cards with a sorting machine.

Mix

From the two card stacks, that card is always fed into the storage compartment that has the lowest value with regard to the sorting criterion. In this way, the cards from the secondary card feeder are shuffled into the primary stack.

Drag or replace

The mixer is programmed in such a way that if there is a match, the corresponding card is fed from the primary stack into a separate output compartment. Alternatively, the card from the second card compartment can then be mixed in (that is, the drawn card replaced) or placed in a further output compartment.

Application examples

As an example, consider a telephone company that punches its customer data on cards, with one address and one telephone number per card. The cards are sorted in decimal ascending order using the punch card sorter according to the telephone number.

exams

The stack of customer cards comes into the primary card feeder. The following program is wired:

  1. Feed the first card into the first scanning station.
  2. When the second scanning station is empty, the card is passed into the second scanning station and the next card is drawn into the first.
  3. Comparison of the telephone numbers between the second and the first scanning station, which number is greater. Depending on the result, define an output compartment and place the card of the second in it, transport the card from the first to the second station, a new one to the first station, then a new comparison.

Result: This checks that the cards are sorted correctly. If it is checked for equality, duplicates can be found.

Maintaining address changes

Some customers have moved but kept their phone number. These are combined in a stack of new customer punch cards, which are sorted in ascending order using the punch card sorter. The pile of new cards with the data of moved customers is mixed in. The previously sorted cards from the customer pile are placed in the primary feed, those who move to the second card feed. The following program sequence is wired:

  1. Comparison for equality between (first) scanning station (customer) and scanning station (moving house) in the telephone number.
  2. If there is no match, place the customer card in compartment 1 (not moved). Withdraw the next customer card. The card under the second card feeder scanning station for the movers is not deposited.
  3. If the phone number is the same, the customer card is placed in compartment 2, the new card (because someone has moved) into compartment 1 and the next cards are drawn in from the stacks in both feeders. The customer has moved, so he has a new address while keeping his phone number.

Result: The current stack of customers is in compartment 1, and the old addresses of the customers are in compartment 2.

Prepare telephone bills

In a telephone company, sales data such as telephone number, call duration, tariff arise. It is assumed that this sales data is punched out, one card per call and sorted in ascending order by phone number.

The tabulating machine masters the four basic arithmetic operations , it can print and has a form control (from 1937). It makes sense to use this for the automated creation of invoices:

The sales stack in the primary feeder. The sorted customer stack in the second card feed (for referencing the customers and addresses).

Programming:

  1. Pull in a card at a time and compare whether the phone numbers are the same. Not the same means: no turnover; Place customer card in compartment 2, draw the next customer. Hold sales card.
  2. If the telephone number is the same, place the customer card in compartment 1; the customer has sales. The customer card has disappeared; no further comparison with her is possible.
  3. The sales card is transported to the second scanning station, so the telephone number is retained. Compare the next sales card in the first and equal to the second.
  4. If they are the same, the sales card is placed in compartment 1 at the second station, and it moves from the first station to the second; a new sales card is drawn and compared.
  5. If inequality is found, the second station is the last sales to be assigned to the customer, that is, a card in compartment 1. In the first scanning station, there is a new telephone number with sales, that is, hold a sales card and pull the next customer card. A classic one.

Result: The stack in compartment 1 has the order Customer1, Sales1-1, Sales1-2; Customer2, Sales2-1, etc. This batch can be processed further using the tabulation machine.

Others

The French word for “computer” parallels the electromechanical punch card mixing and sorting technique described above: ordinateur (“folder, sequence maker”).

literature

Web links

Individual evidence

  1. ↑ Type 077 Collator in English Diagram and functional description in English
  2. ↑ IBM Collators IBM developed the first devices for the US Social Security Administration in 1937.