Adaptation middleware is becoming widely used to build adaptive collaborative applications. However, collaborative applications requiring real-time services are intolerant of the long reconfiguration time of the existing adaptation middleware, which is in a range of seconds or even tens of seconds. In this paper, we present MARCHES, which is active message oriented adaptation middleware that reduces the reconfiguration time. Different from the traditional middleware that supports the single

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... onent-chain based application architecture, MARCHES maintains multiple component chains or actuators. Then the process of architecture reconfiguration is done by a new method of switching active and inactive actuators, which replaces the traditional method of modifying the single-chain architecture. An active message based synchronization protocol is proposed according to the new method to reduce the communication overhead and reconfiguration time. Experiment results demonstrate that MARCHES improves the packet delivery ratio and throughput of collaborative applications. Results also show that the reconfiguration time achieved by MARCHES is in a range of hundreds of microseconds and the extra costs introduced by the multi-actuator architecture are extremely low.