Client Server design and implementation issues in the Accelerator Control System environment

In distributed system communication software design, the Client-Server model has been widely used. This paper addresses the design and implementation issues of such a model, particularly when used in Accelerator Control Systems. In designing the Client-Server model one needs to decide how the services will be defined for a server, what types of messages the server will respond to, which data formats will be used for the network transactions and how the server will be located by the client. Special consideration needs to be given to error handling both on the server and client side. Since the server is usually located on a machine other than the client, easy and informative server diagnostic capability is required. The higher level abstraction provided by the Client-Server model simplifies the application writing, but fine control over the network parameters is essential to provide the performance required. These design issues and implementation trade-offs are discussed in this paper. 1.