MUMPS, or M, is a general-purpose computer programming language that provides ACID transaction processing. Its differentiating feature is its built-in database, enabling high-level access to disk storage using simple symbolic program variables and subscripted arrays, similar to the variables used by most languages to access main memory. The M database is a key-value database engine optimized for high-throughput transaction processing. As such it is in the class of schema-less, schema-free,