2003/07/10 by Karen D. Kotturi, Kotturi, Karen D.
Computer Science · Physics and Astronomy · #C.2.3 #Distributed and Parallel Computing Systems #FOS: Computer and information sciences #Networking and Internet Architecture (cs.NI) #Particle Detector Development and Performance #Radiation Detection and Scintillator Technologies #cs.NI
paper · pdf · doi:10.48550/arxiv.cs/0307026
arxiv created 2003/07/10 · openalex publication_date 2003/07/10 · arxiv updated 2011/11/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It starts out innocently enough - users want to monitor Online data and so run their own copies of the detector control GUIs in their offices and at home. But over time, the number of processes making requests for values to display on GUIs, webpages and stripcharts can grow, and affect the performance of an Input/Output Controller (IOC) such that it is unable to respond to requests from requests critical to data-taking. At worst, an IOC can hang, its CPU having been allocated 100% to responding to network requests. For the BaBar Online Detector Control System, we were able to eliminate this problem and make great gains in security by moving all of the IOCs to a non-routed, virtual LAN and by enlisting a workstation with two network interface cards to act as the interface between the virtual LAN and the public BaBar network. On the interface machine, we run the Experimental Physics Industrial Control System (EPICS) Channel Access (CA) gateway software (originating from Advanced Photon Source). This software accepts as inputs, all the channels which are loaded into the EPICS databases on all the IOCs. It polls them to update its copy of the values. It answers requests from applications by sending them the currently cached value. We adopted the requirement that data-taking would be independent of the gateway, so that, in the event of a gateway failure, data-taking would be uninterrupted. In this way, we avoided introducing any new risk elements to data-taking. Security rules already in use by the IOC were propagated to the gateway's own security rules and the security of the IOCs themselves was improved by removing them from the public BaBar network.