Online: a program to display histograms and control monitor processes on the WA62 VAX data acquisition system at CERN

ONLINE is a program which can be launched from any terminal on the WA62 experiment's DEC VAX 11/780 computer when the Native mode data acquisition system is running. It is used to display histograms produced by the various experiment monitor processes running under the system and can establish links with such processes to allow the user to issue monitor commands and change internal monitor process parameters. This report describes the criteria used in the design of ONLINE and shows some of the features of the VAX/VMS Operating System which are used to access histograms produced by monitor processes, to establish communications links with monitor processes and to provide the user with an easy to learn system for the examination of online experimental data in a graphical form. Also given, is a brief account of the way monitor processes are structured and how this structure facilitates user-monitor dialogue. (author)