VME-computer network (MAP) for the KEK proton synchrotron

A VME-computer-based system was chosen to replace the old minicomputer-based system for the KEK (Japan National Laboratory for High-Energy Physics) proton synchrotron. More than 20 node computers are connected with each other through a broadband token-bus network called MAP (Manufacturing Automation Protocol). The nodes are categorized into four types: a network management node (NM), a software development node (SW), operator console nodes (OPs), and equipment control nodes (HW) that control accelerator equipment. System and application programs of any node except the SW and the NM are downloaded from the NM and/or the SW. The MAP version 2.1 with File Transfer Access and Management (FTAM) and Common Application Service Element (CASE) is supported at present. The performance of the network is acceptable. There are many parameters which need to be tuned up to raise the network performance. The total data transfer throughout the network is estimated to be about 300 kB/s