Mem (computing), a measurement unit for the number of memory accesses used or needed by a process, function, instruction set, algorithm or data structure
Microelectromechanical systems, the technology of very small devices
Modular Engine Management System, an electronic control system used on engines in passenger cars built by Rover Group
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Microelectromechanical systems (MEMS, also written as micro-electro-mechanical, MicroElectroMechanical or microelectronic and microelectromechanical systems and the related micromechatronics) is the technology of very small devices; it merges at the nano-scale into nanoelectromechanical systems (NEMS) and nanotechnology. MEMS are also referred to as micromachines in Japan, or micro systems technology (MST) in Europe.
Micro-electro-mechanical system: Mirrors, no larger in diameter than a human hair, which can be arranged on special pivots so that they can be moved in 3 dimensions. Several hundred such mirrors can be placed together on mirror arrays no more than a few centimeters square in size, to form an optical crossconnect.