Used to describe equipment that is non-functional and halfway expected to remain so, especially obsolete equipment kept around for political reasons or ostensibly as a backup. "When we get another Wyse-50 in here, that ADM 3 will turn into a doorstop."
Compare boat anchor.
[Jargon File]
usually decorative and invariably heavy object used to prevent doors from swinging shut. Doorstops came into use about 1775 following the introduction of the rising butt, a type of hinge designed to close a door automatically. Many stops took the form of famous persons, such as Napoleon, Shakespeare, Wellington, Gladstone, and Disraeli. Animal forms were also popular