Before Computers—The Tab Card Epoch
by Charles Bovaird
Before computers there were tabulators. Before
tabulators there were calculators. Before calculators there were
analog calculators. Before analog calculators computation was
performed using writing instruments and mental calculations.
An example is the (25.5” x 14”). Accountant’s
21 column WORKSHEET illustrated here
Tabulating machines relied on input data in
the form of punched cards. These electromechanical machines used
electrical relays to control the card transport mechanism, mechanical
storage devices, and the printing mechanics.
A special purpose electromechanical calculator
example is The Turing Bombe used for code breaking (crypto-analysis)
during WWII.
Other mechanical calculators used in business
during the tabulating epoch are the Comptometer, the Marchant,
and the Monroe calculating machines.
Examples of analog calculators are the slide
rule, astrolabe, abacus, logarithmic tables, and Artillery firing
tables.
Examples of writing instruments, paper, pen,
chalk, blackboards, papyrus, and blackboards.
Accounting students in the 50’s used
14 and 21 column accounting forms (illustrated) also referred
to as Tab Sheets or worksheets for managing account data. This
involved cross posting account values into appropriate column
categories, manually adding up the columns, validating the column
sums, and resolving any posting or addition errors. Tabulators
and calculators were not available in the classroom. Slide rules
were used in some courses. Education in the use of logarithmic
tables was standard.
Treating each of these epochs, history shows
there is overlap between one epoch and the next.
This article will focus in on the tabulator
epoch experienced by the author and defined by the IBM tabulating
card. During this epoch other companies were competing in the
commercial business tabulator market though IBM was dominant.
The tabulator epoch began about 1860 and was
initiated by Herman Hollerith's invention of the tabulating machine
used to process data for the 1890 U.S. Census.
The tabulator epoch ended about 1968 when the
punched card equipment was no longer used inside IBM. The punched
cards demise started about 1950 with the introduction of large
commercial electronic computers using vacuum tube technology
and magnetic tape media. During this period source data was read
from punched cards and written on magnetic tape. Later, punched
cards were displaced by typewriter keyboard devices controlled
to write on to magnetic tapes. The magnetic tapes were then used
as input to computers. In some cases punched tape was used. Typewriter
keyboard devices were later displaced by monitor/keyboard devices
(IBM 3270).
Thee IBM punchcard measured 3 1/4" x 7
3/8". It came 2000 cards to a box. The card columns were
numbered left to right one through 80. The card rows were identified
top to bottom as 12, 11, 0,1,2,3,4,5,6,7,8,9 respectively.
The IBM tab card illustrated here was found
stapled to the bottom of a furniture cabinet. They could be ordered
with printing tied to specific job processes. The card-punch
machine could print the characters that represented the columnar
punched holes. This card was used on IBM 360 machines and the
punched holes were coded for alphanumeric interpretation. The
12 rows from top to bottom were 12, 11, 0 ,1, 2, 3, 4, 5, 6,
7, 8, 9. The letters A to I used a 12 punch, J to S and 11 punch,
T to Z a 0 punch. Special characters and punctuation required
three holes per column. Cards had the top left corner cut to
assist in card orientation relative to other cards in a deck
of cards.
Tabulating operations required processing an
ordered sequence of cards. To prepare the cards for tabulation
required the use of card punches, card sorters, and card collators.
Throughout the tabulating epoch machines improved
in card processing speed and card handling reliability. A tabulating
job could require one or more card decks with some jobs requiring
thousands of cards. Card decks were manually transported between
card punching machines, sorters, collators, and tabulator. The
output of a tabulator was a series of printed reports. Many looked
like a current spreadsheets or database reports. The machines,
as a group, were referred to as Electronic Accounting Machines
(EAM).
Sorting machines
A deck of tabulating cards had to be run through
the sorter column by column. If there were multiple punches in
a column it had to be run through the machine has many times
as there were punches in that column. To control this each run
required setting some tabs to select the appropriate row selection
settings. The operator had to collect the cards from the individual
hoppers in the proper sequence and place them in holding racks
above the sorter in such a way that the order was maintained.
The quality of the process required skilled operators and a high
degree of cooperation between individuals on the data processing
floor as well as between operating shifts. Any error introduced
by card handling or machine error would likely require starting
the sort over from the beginning.
Collating machines
Collating machines were used to merge two sequenced
card decks into one. The collator had a wired plug board to control
the field selections and merge sequence rules. Different plugboards
were used for each unique collating process. The correct board
had to be placed in the collator before running a job related
collating sequence.
Tabulating machines
Tabulating machines were the most complex.
They had a card reader, a wired plug-board control panel, a mechanical
printing mechanism, and banks of relays. The typical tabulator
could handle paper of various widths up to 120 characters across.
Tabulating totals and logic were managed by wiring the plug board
control panel. Up to five-part carbon paper could be used. Printing
was accomplished by moving the pin feed paper into the proper
vertical position where a row of print could occur. For each
column the appropriate type slug would be aligned with each print
hammer position. Each hammer would smash the paper into an inked
ribbon and into the type slug. Multiple hammers firing to create
a line of print was quite noisy. Multiple tabulators running
in the same room sounded like a foundry.
Additional background on tabulating machines
can be found at:
http://en.wikipedia.org/wiki/Tabulating_machine and http://en.wikipedia.org/wiki/IBM_407.
It is important to note that during the tabulation
card epoch customers bought the use of machines by rental agreements.
Machine repairs were included in the rental cost however since
machine down situations could adversely affect processing schedules
and costs, the reliability of installed machines and the quality
of the repair effort was a key value to both the customer and
the supplier. In IBM employees who repaired machines were called “Customer
Engineers” to identify the true scope of their responsibilities.
Punched card systems played a key role in the
1890 US census, the implementation of the Social Security system,
and World War II armed forces supplies management. Written lists
or a deck of punched cards were the data storage device of this
epoch.
Next – the vacuum tube computer epoch
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