The tub file was a technique used in the
punched card
A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...
era to speed generation of data files. Multiple copies of frequently used cards were prepunched and stored in trays with index tabs between card sets, arranged so that cards would be easy to find.
This technique was an early form of
random access memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to b ...
.
Example
A wholesaler might have a tub file with cards for frequent customers and for each inventory item. Instead of
keypunch
A keypunch is a device for precisely punching holes into stiff paper cards at specific locations as determined by keys struck by a human operator. Other devices included here for that same function include the gang punch, the pantograph punch, ...
ing a set of cards for each purchase order, a clerk would pull out one customer card and then a card for each item that customer ordered. The resulting deck could then be run through a
tabulating machine
The tabulating machine was an electromechanical machine designed to assist in summarizing information stored on punched cards. Invented by Herman Hollerith, the machine was developed to help process data for the 1890 U.S. Census. Later models w ...
to produce an invoice.
In this example item cards also provided
inventory control
Inventory control or stock control can be broadly defined as "the activity of checking a shop's stock". It is the process of ensuring that the right amount of supply is available within a business. However, a more focused definition takes into acco ...
, since each card presumably represented one item in stock, so it was simple to check availability and schedule reordering.
References
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External links
Photo of workers using a tub file*''RAMAC Oral History Project'',
Computer History Museum
The Computer History Museum (CHM) is a museum of computer history, located in Mountain View, California. The museum presents stories and artifacts of Silicon Valley and the information age, and explores the computing revolution and its impact on ...
, at 26:21
Punched card
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