In one form or another, S has been available by license from Bell Laboratories since the early 1980s. Since about 1993, this license has had the form of an exclusive license, held by the makers of S-Plus, the MathSoft Corporation. Exclusivity means that the license holder has the exclusive right to sell products incorporating S. In effect, S is available exclusively in the form of the S-Plus system. The S software coming from research at Bell Labs is supplied to MathSoft, who provide modifications and additions to create S-Plus and other software products, as well as providing support, education, and other services. As of the last updating of this page, MathSoft was offering S-Plus 5.0, based on the version of S described in Programming with Data, for Solaris and Linux platforms. See their web site for up-to-date information on the products and platforms available.