MES: Manufacturing Execution System, 制造执行管理系统。按MESA国际联合的定义，MES能通过信息的传递，对从订单下达开始到产品完成的整个产品生产过程进行优化的管理，对工厂发生的实时事件，及时作出相应的反应和报告，并用当前准确的数据对进行相应的指导和处理。

Why MES
Short lead-time, rush order
Lack of collaboration with business partners
Quality not stable
Business process always changing
Cost is hard to calculate
Hard to evaluate the performance of plant
Hard to get real-time status of production
Lack of information to support decision making
...