Real time processor in JT-60 data processing system

Real time processor, RTP, is a basic subsystem in the JT-60 data processing system and plays an important role in JT-60 feedback control utilizing var ious diagnostic signals. An original mini-computer system was replaced in 1 994 with a workstation. It has 2 CPU's with a real-time parallel UNIX. Duri ng the experiment, one CPU communicates with the main computer synchronized with the experimental sequence, and the other executes a real-time process with 1 ms clock. RTP has been upgraded to a compatible RISC workstation wi th a faster A/D converter in 1997 in response to increased requests of hand ling the increased signals in more complicated manners. After this upgrade, an elapsed time is reduced to similar to 75% and an I/O time is now domina nt. To reduce a CAMAC access time, we try to use a reflective memory for th e data transfer. Now RTP handles six kinds of signals to control an electro n density, a neutron emission, an electron density and a radiation in the d ivertor region, and a neutral pressure. RTP will handle five more kinds of signals this year and be used for an advanced control with more complicated processing. (C) 2000 Elsevier Science S.A. All rights reserved.