The Dynascope Directing Server: Design and Implementation

As computer systems are becoming increasingly complex, directing tools are gaining in importance. Directing denotes two classes of activi- ties, monitoring and controlling. Monitoring is used for collecting information about the program behav- ior. Controlling is used to modify the program state in order to change the program's future behavior. Some characteristic directing tools are debuggers and perfor- mance monitors. Dynascope is a directing platform, which pro- vides basic monitoring and controlling primitives. These primitives are used in building advanced di- recting applications for networked and heterogeneous environments. Dynascope is integrated with existing programming tools and uses only generic operating system and networking primitives. This paper describes the design and implementation of the directing server, the central component of Dynascope. Dynascope is being used in several applications, including relative debugging, steering agents, and simulator testing.