Mini SQL (mSQL) is a lightweight client/server database developed by Hughes Technologies in 1994. mSQL filled a gap that existed between the embedded desktop databases like Microsoft Access and the enterprise-level commercial databases such as Oracle and DB2. It was popular database of choice for open source developers in the middle of 90'. By 1996, development on mSQL began to stagnate and MySQL arose to fill that void. By 1999, MySQL had gone well beyond mSQL in popularity and today mSQL has less visibility.

mSQL-JDBC is an Open Source Type IV Java Database Connectivity (JDBC) driver for the mSQL database engine created by George Reese. It is written in the Java programming language and uses the native mSQL network protocols to talk to mSQL. The driver supports as much of the JDBC specification as the mSQL database will support, but development on the driver basically ceased in 1997. The driver therefore does not support the most recent releases (3.0 and above) of mSQL.

Minimal SYStem(MSYS), a part of MinGW, was created out of a long-lived desire to provide the MinGW community a Minimal SYStem, with which a configure script could be executed. MSYS provides POSIX/Bourne configure scripts the ability to execute and create a Makefile used by make. MSYS versions 1.0.8 and later include only the i386 binary distribution, which will run on any 32-bit Intel-compatible processor.

The Magic User Interface(MUI) is an object oriented system by Stefan Stuntz to generate and maintain graphical user interfaces. The MUI was written for AmigaOS and gained popularity amongst both programmers and users. It has been ported to PowerPC processors and adopted as the default GUI toolkit of the MorphOS operating system. The MUI application programmer interface has been cloned by the Zune toolkit used in the Amiga Research Operating System.

Multiple perspective software development refers to an approach to software development which requires communication and collaboration between experts in a number of different fields.

Multiprocessing typically refers to the use of more than one processor (CPU) in a single computer system. So-called multiprocessor systems usually have a common memory space through which all of the processors can communicate and share data. Multiprocessing sometimes refers to the execution of multiple concurrent software processes in a system as opposed to a single process at any one instant.

In computing, multitasking is technique used in an operating system for sharing a single processor between several independent jobs. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for that task. Multitasking solves the problem by scheduling which task may be the one running at any given time, and when another waiting task gets a turn. The act of reassigning a CPU from one task to another one is called a context switch. When context switches occur frequently enough the illusion of parallelism is achieved. Even on computers with more than one CPU, multitasking allows many more tasks to be run than there are CPUs.

Multithreading typically refers to sharing a single CPU between multiple tasks (or "threads") in a way designed to minimise the time required to switch threads. This is accomplished by sharing as much as possible of the program execution environment between the different threads so that very little state needs to be saved and restored when changing thread. Multiple threads can be executed in parallel on many computer systems. This multithreading generally occurs by time slicing, wherein a single processor switches between different threads--in which case the processing is not literally "simultaneous", for the single processor is only really doing one thing at a time. On a multiprocessor system, threading can be achieved via multiprocessing, wherein different threads can run simultaneously on different processors.

MusE is a MIDI/Audio sequencer program with recording and editing capabilities written by Werner Schweer. MusE aims to be a complete multitrack virtual studio for Linux (it currently has no support under other platforms, due to its reliance on JACK and ALSA). It is published under the GNU General Public License.

MySQL is a multithreaded, multi-user, SQL (Structured Query Language) Database Management System (DBMS). MySQL is open source software available either under the GNU General Public License (GPL) or under other licenses when the GPL is inapplicable to the intended use.