What is the etymology of the word "backup" (in the meaning of "a file copy" in computing)? I can't find the origin and the first using of this word in this very meaning. Why is "backup" so called?

There are some sources like this which writes about the first using of "back up" in 1767 and this which writes about the first using of "backup" in 1775 or 1952 (this). But there are no text examples.

  • Specific reference to computing is from 1965. etymonline.com/word/backup
    – user 66974
    Commented Sep 2, 2018 at 7:35
  • 2
    In earlier times a file copy would be a carbon copy of a typewritten business letter, kept in a correspondence file so there was a record of what had been sent. Commented Sep 2, 2018 at 7:36
  • @KateBunting do you have more information about this? Commented Sep 2, 2018 at 9:28
  • Only that I'm old enough to remember pre-computer business practices! When all documents had to be produced on a typewriter, the typist would insert two sheets of paper with carbon paper between them. This was thin, strong paper coated on one side with a black substance, which was transferred to the second sheet of paper making a duplicate copy of the document. Even earlier, when business letters were handwritten, the clerk would have to copy out the letter into a book so that the firm had a record of it. Commented Sep 2, 2018 at 16:59
  • @JEL I mean "backup" origin. You write "I have text evidence of the use of 'back-up copy' in computing as early as 1957" — it's interesting for me. Commented Sep 3, 2018 at 7:46

1 Answer 1


Attributive use of the noun 'back-up' (also 'backup') in the sense of "stand-by, reserve" is attested as early as 1952 in OED:

Orig[inally] U.S....Also attrib[utive] spec[ifically] in Computing, (the making of) a duplicate copy of a disc, file, etc., for use in case of loss or corruption of the original.

1952 Wall St. Jrnl. 5 June 18 Value of the stocks, including 'back-up' supplies being held in warehouses for order filling, will total about £1 million.

Use in computing, as noted in OED, is not attested there until 1964; in 1965, the preparation of backup files is implied by the use attested:

1964 CIS Gloss. Automated Typesetting (Composition Information Services) 3 A back-up computer may be located in the same plant or hundreds of miles away.
1965 Proc. AFIPS Conf. 27 193/1 The backup procedures must be prepared for contingencies ranging from a dropped bit on a magnetic tape to a fire.

However, 'back-up' is used attributively in computing, in the phrases "back-up copy" and "back-up file", at least as early as 1957 and 1962, respectively:

When the tape has been written, a copy should be made to serve as a back-up copy. This tape will contain seven binary files.

"TURBO : a two-dimensional few-group depletion code for the IBM-704*, J.B. Callaghan et al., November 1957. Emphasis mine.

Since the punched deck is always maintained up-to-date, it provides a back-up file for the descriptor card catalog.

Electrical and electronic properties of materials information retrieval program, final report, by H. Thayne Johnson et al., June 1962. Emphasis mine.

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