GT.M

GT.M is a high-throughput key-value database engine optimized for transaction processing. (It is a type also referred to as "schema-less", "schema-free," or "NoSQL.") GT.M is also an application development platform and a compiler for the ISO standard M language, also known as MUMPS.

GT.M, an abbreviation for Greystone Technology M, was developed by the Greystone Technology Corp in the 1980s. It is an implementation of ANSI standard M for various UNIX systems and OpenVMS. In addition to preserving the traditional features of M, GT.M also offers an optimizing compiler that produces object code that does not require internal interpreters during execution.

The database engine, made open source in 2000, is maintained by Fidelity Information Services. GT.M is used as the backend of their FIS Profile banking application, and it powers ING DIRECT banks in the United States, Canada, Spain, France, Italy, Holland and the UK. It is also used as an open source backend for the Electronic Health Record system WorldVistA and other open source EHRs such as Medsphere's OpenVista. It is listed as an open source healthcare solution partner of Red Hat. Today it consists of approximately 2 million lines of code.