The Remington Rand 409, is a series of punched card calculators that were programmed with a plugboard. The prototype model was designed in 1949 and finished completion in 1951.

The commercial version was sold in three models:

The model number referred to the number of decimal digits the device could read from each punched card.

The machine was designed in "The Barn", at 33 Highland Ave. in Rowayton, Connecticut, a building that currently houses the Rowayton Public Library and Community Center.

These machines were discontinued when the UNIVAC 1004 was introduced in 1962. A total of 1080 units of the series had been produced by the end of 1961.

Architecture

Numbers were fixed-point and of variable length (one to ten digits). Arithmetic was done in floating point, but all results were converted to fixed point when stored in memory.

Digits are represented in bi-quinary coded decimal. Each digit of memory storage contained five tubes. Four of these represented the digits 1, 3, 5, and 7, while the fifth tube represented 9 if activated alone but added 1 to the value if activated together with another tube.

Hardware

See also

• List of UNIVAC products

• History of computing hardware

• List of vacuum-tube computers

Notes

Further reading

• Electronic Brains: Stories from the dawn of the computer age, chapter 3 (pp.53–73), Mike Hally, 2005, ISBN 978-0-309-09630-0.

External links

• Rowayton, Connecticut: Birthplace of the World's First Business Computer

• Rowayton Public Library Website

• Universal Automatic Computer Model 60 A Third Survey of Domestic Electronic Digital Computing Systems Report No. 1115, March 1961 by Martin H. Weik

• Universal Autometic Computer Model 120 A Third Survey of Domestic Electronic Digital Computing Systems Report No. 1115, March 1961 by Martin H. Weik

• Service and Programming documentation at bitsavers.org