在計算機軟件中，定時炸彈是已編寫的計算機程序的一部分，它會在達到預定日期或時間後開始或停止運行。「定時炸彈」不是指安裝後特定天數停止運行的程序；相反，「試用軟件」適用。當軟件製造商不希望在最終發佈日期之後使用測試版時，定時炸彈通常用於測試版（預發佈）軟件。定時炸彈軟件的一個例子是微軟的Windows Vista Beta 2 ，它被編程為 2007 年 5 月 31 日到期 。
軟件中第一次使用定時炸彈可能是由Brian Reid開發的Scribe。 Reid把Scribe賣給了一家名為 Unilogic（後來更名為 Scribe Systems [1] ）的軟件公司，並同意插入一組與時間相關的函數（稱為「定時炸彈」），這些函數將在 90天之後停用自由複製的程序版本。 [2]
理查德·斯托曼認為這是對程式設計師精神的背叛。 Reid沒有尊重共享和共享的概念，而是為公司插入了一種方法，迫使程式設計師為信息訪問付費。[3]
Williams, Sam. Free as in Freedom – Richard Stallman's Crusade for Free Software. O'Reilly. March 2002 [2008-09-26]. （原始內容存檔於2015-09-10）. In 1979, Reid made the decision to sell Scribe to a Pittsburgh-area software company called Unilogic. His graduate-student career ending, Reid says he simply was looking for a way to unload the program on a set of developers that would take pains to keep it from slipping into the public domain. To sweeten the deal, Reid also agreed to insert a set of time-dependent functions- "time bombs" in software-programmer parlance-that deactivated 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 disabled the internal time-bomb feature.
Williams, Sam. Free as in Freedom – Richard Stallman's Crusade for Free Software. O'Reilly. March 2002 [2008-09-26]. （原始內容存檔於2015-09-10）. For Reid, the deal was a win-win. Scribe didn't fall into the public domain, and Unilogic recouped on its investment. For Stallman, it was a betrayal of the programmer ethos, pure and simple. 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.
