USA - 2020
For Berkeley DB, which was an early exemplar of the NoSQL movement and pioneered the "dual-license" approach to software licensing
Since 1991, Berkeley DB has been a pervasive force underlying the modern Internet: It is a part of nearly every POSIX or POSIX-like system, as well as the GNU standard C library (glibc) and many higher-level scripting languages. Berkeley DB was the transactional key/value store for a range of first- and second-generation Internet services, including account management, mail and identity servers, online trading platforms and many other software-as-a-service platforms.
As an open source package, Berkeley DB is an invaluable teaching tool, allowing students to see under the hood of a tool that they have grown familiar with by use. The code is clean, well structured, and well documented -- it had to be as it was meant to be consumed and used by an unlimited number of software developers.
As originally created by Seltzer, Olson and Bostic, Berkeley DB was distributed as part of the University of California's Fourth Berkeley Software Distribution. Seltzer and Bostic subsequently founded Sleepycat Software in 1996 to continue development of Berkeley DB and provide commercial support. Olson joined in 1997, and for ten years, Berkeley DB was the de facto data store for major web infrastructure. As the first production quality, commercial key/value store, it helped launched the NoSQL movement; as the engine behind Amazon's Dynamo and the University of Michigan's SLAPD server, Berkeley DB helped move non-relational databases into the public eye.
Sleepycat Software pioneered the "dual-license" model of software licensing: use and redistribution in Open Source applications was always free, and companies could choose a commercial license for support or to distribute Berkeley DB as part of proprietary packages. This model led the way to a number of other open source companies, and this innovation has been widely adopted in open source communities. The open source Berkeley DB release includes all the features of the complete commercial version, and developers building prototypes with open source releases suffer no delay when transitioning to a proprietary product that embeds Berkeley DB
In summary, Berkeley DB has been one of the most useful, powerful, reliable, and long-lived software packages. The longevity of Berkeley DB's contribution is particularly impressive in an industry with frequent software system turnover.