http://motherboard.vice.com/read/meet-mumps-the-archaic-health-care-programming-language-that-predicted-big-data-2

http://gradvs1.mgateway.com/download/extreme1.pdf

"MUMPS is unusual in that it is two things at once: a language and a database," explains Rob Tweed, a longtime MUMPS developer (and, yes, booster), at the EWD Files. "More accurately it’s a database with an integrated language that is optimized for accessing and manipulating that database. It was originally designed for use in a medical/clinical setting, but in meeting the non-trivial needs of that setting, it happened to pre-empt the now hyper-trendy NoSQL database design goals by several decades. It’s an exceptionally high-performance database with an equally high-performance language, capable of massive scalability."

When a user is doing something with an SQL database (or other relational database), whether they're adding to it or retrieving from it, they're performing a "query" operation, which is built into the database software. This is an abstraction intended to hide the guts of the database from the user, who only needs to interface with it via this one query command. But the thing about abstraction in computer science, whether it's a high-level virtual machine-based programming language like Java or a bare-bones Unix shell, is that it always has a cost. In a database, this might be the speed by which some piece of data can be stored or accessed. The query operation is simpler for the end user (the database programmer, that is), but slower and clumsier.

MUMPS is based on storing data in simple arrays that are accessed using a key. Imagine just a long list of things with each item having its own unique designation referred to by a variable. Variables (or keys, in this case) are just addresses of different memory locations within those arrays, which are called globals in MUMPS-speak. A MUMPS system, which might be made up of many computers, has its own collection of global arrays stored in non-volatile memory. So, unlike an array created in a language like C++, which exists only for the duration of the program or the program's existence within a computer's RAM address space, a MUMPS global sticks around on a server, accessible at any given time to a computer within the system by the addition of the "^" character. We say that it's persistent.