formal software verification tool

 Spin is a popular open-source software verification tool, used by thousands
 of people worldwide. The tool can be used for the formal verification of
 multi-threaded software applications. The tool was developed at Bell Labs
 in the Unix group of the Computing Sciences Research Center, starting in 1980.
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 The software has been available freely since 1991, and continues to evolve to
 keep pace with new developments.
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 In April 2002 the tool was awarded the ACM System Software Award.