Development of Device Drivers on Real-time UNIX for the SPring-8
Storage Ring Control System

T. Masuda, S. Fujiwara, T. Fukui, A. Taketani,R. Tanaka,
T. Wada, W. Xu, and A. Yamashita

SPring-8 , Kamigori, Ako-gun, Hyogo 678-12, Japan

A distributed computing system has been adopted for the SPring-8 storage ring control system. We use VME computer system with real-time UNIX for front-end controller. The selecting criteria of the operating system were mainly real-time features and open system features, that is, compliance with POSIX standard. Among such OS's, HP-RT, LynxOS migrated to the PA-RISC based CPU board, was chosen. HP-RT with PA-RISC system is installed in 27 VME controllers in the storage ring.

The device drivers were developed for VME boards such as DI, DO, TTL DI, TTL DIO, AI, PTG, GP-IB interface, and RIO(Remote I/O) by using SWSM(System Wide Shared Memory) structure of HP-RT. The optical-linked RIO system is substantially used as the field-bus for the control of magnet power supplies, vacuum system, and beam position monitoring system.