Calvin Northrup Mooers

Calvin Mooers (1919-1994) was an American information retrieval specialist.

Life

Calvin Northrup Mooers was born on October 24, 1919. He graduated BA summa cum laude at the University of Minnesota in 1941 and joined the Naval Ordnance Laboratory as a physicist. At the end of the war he became part of the Lab's newly created Computer Division under John Vincent Atanasoff. Mooers left in 1946 for MIT where he met James Perry and became interested in information retrieval. In 1947 Mooers founded a company, “Zator,” and began marketing a custom-designed mechanical retrieval systems using edge-notched cards. He completed a Master's thesis on Application of random codes to gathering of statistical information. Mooers founded the Rockford Research Institute, a nonprofit corporation, in the early 1960s to facilitate his and Raymond J. Solomonoff’s grant-funded research. He died on December 1, 1994.

Contributions

TRAC programming language. In 1959, Mooers began to develop the Text Reckoning and Compiling (TRAC) language.
Mooers coined the terms "information retrieval" in 1950 and "descriptors."
He promulgated "Mooers' Law" on the use of information: That an information will not be used if using it is more work than not using it.

Zatocoding

Although Mooers was involved in the early design of digital computers, he made his name through his development of Zatocoding for edge-notched cards. Before the 1980s individuals made heavy use of cards which had a row of small round holes along the edges of a card. Cutting away card between the hole and the edge left a notch instead of a hole. In a simple case each card might represent a book and each hole represented a possible feature (attribute), such as a topic of the book. Notching the hole for "history" would mean that it was a history book. Notching a hole representing "France" would encode a book about France. Notching both the "history" and the "France" holes would mean a book on the history of France. Cards with desired notches were immediately identifiable by inserting needle through the holes (codes) of interest and lifting. Intact (unnotched) cards would be lifted; notched cards would remain unlifted. In a simple system in which each hole had a single meaning, the number of usable codes (attributes) was limited because the number of codes could not exceed the number of holes. Mooers explored the potential of using combinations of two or more holes to represent a single code. This meant, in theory, that there could be as many different codes as there were unique combinations of holes. A single hole might be part of multiple combinations but each combination of holes should represent only a single code. In the mechanical system that the Zator company marketed each card had just 40 holes along the bottom edge. By using combinations of holes up to 10,000 different codes could be uniquely encoded -- and any cards wrongly retrieved ("false drops") should be obvious errors. Mooers explored the effects of assigning combinations of holes to codes at random. He concluded that conventional single hole coding was superior for codes having little variety and high frequency, but that Zatocoding had a complementary advantage for codes with large variety and low frequency. This technique can also be applied to encoding the positions on punch cards and is also known as superimposed coding. It is a form of what in computing is called a hash code. (See Further reading below).

Publications

"Atanasoff at the Naval Ordnance Laboratory." Annals of the History of Computing 15:2 (1993), 54-55.
"TRAC, a Procedure-Describing Language for the Reactive Typewriter." CACM, 9:3 (March 1966), 215-219.
Putting Probability to Work in Coding Punched Cards: Zatocoding. (Zator Technical Bulletin No. 10), 1947. Reprinted as Zator Technical Bulletin No. 30 (1950).
The Zator - A Proposal: A Machine for Complete Documentation, 1947. Reprinted with preface as Zator Technical Bulletin No. 65 (1951).
"Zatocoding applied to mechanical organization of knowledge." American documentation 2, issue 1 (Jan 1951): 20-32.
"'Mooers' Law or Why some retrieval systems are used and others are not." Bulletin of the American Society for Information Science 22, no 1 (Nov 1996): 22-23.[1]
Calvin N. and Charlotte D. Mooers oral history interview, 22 June 1993, OH 254,

Awards

American Society for Information Science. Award of Merit, 1978.

Papers

University of Minnesota, Babbage Institute, Minneapolis, MN. Calvin N. Mooers papers CBI 81 55455. ca. 1930-1994. Finding aid [4]