In computer software
, a time bomb
refers to a computer program
that has been written so that it will stop functioning after a predetermined date or time is reached. The term "time bomb" does not refer to a program that stops functioning a specific number of days after it is installed; instead, the term "trialware
" applies. Time bombs are commonly used in beta
(pre-release) software when the manufacturer of the software does not want the beta version being used after the final release date. One example of time bomb software would be Microsoft's Windows Vista
Beta 2, which was programmed to expire on May 31
. The time limits on time bomb software are not usually as heavily enforced as they are on trial software
, since time bomb software does not usually implement secure clock
The first use of a time bomb in software may have been with the Scribe
markup language and word processing system, developed by Brian Reid
. Reid sold Scribe to a software company called Unilogic, and agreed to insert a set of time-dependent functions (called "time bombs") that would deactivate freely copied versions of the program after a 90-day expiration date. To avoid deactivation, users paid the software company, which then issued a code that defused the internal time bomb feature.
Richard Stallman saw this as a betrayal of the programmer ethos. Instead of honoring the notion of share-and-share alike, Reid had inserted a way for companies to compel programmers to pay for information access (see MIT's hacker culture declines).