VAX Online System - A Modular Approach

An approach to developing Online Systems for the VAX, under VMS, is described. A framework for integrating separate and diverse programs into a unified whole is described. Included in this is a scheme which permits multiple VAX processes to share the same terminal in an organized way. This makes use of a menu package, (MENCOM), which also permits a command line mode of operation, with dynamic switching between menu and command line mode. A single DISPLAY program can display the histograms of any program in the system, both the in-memory histograms and those previously stored on disk. A centralized message system is designed to handle all error and status messages. A general buffer scheme used to enter data from any input stream and to access data selectively, is briefly described. This buffer scheme is covered in more detail, by D. Quarrie in his CDF Data Acquisition System paper, given at this conference.