1. Use of ROOT in the D0 Online Event Monitoring System Joel Snow, D0 Collaboration, February 2000

2.  Three Major Components  Data Acquisition System  Monitoring Executables  Graphical User Interface D0 Online Event Monitoring System  Three Operating Systems  Software Portability Joel Snow, D0 Collaboration, February 2000

3.  Provides Portability Physics analysis tools Shared memory Network sockets Graphical widgets ROOTFramework ROOT Framework ROOT is an attractive choice for online monitoring applications Joel Snow, D0 Collaboration, February 2000

4. DataAcquisition System Data Acquisition System  Front-end electronics  Two levels of hardware triggers  Software trigger  Data transfer system Joel Snow, D0 Collaboration, February 2000

5. D0 Run II Online Event Monitoring Architecture

6. Buffer Disk Data Distributor Data Distributor EXAMINE Data Logger Data Logger EXAMINE L3 Filter Node L3 Filter Node Collector / Router Collector / Router L3 Filter Node L3 Filter Node 100 Mb Switch L3 Filter Node L3 Filter Node L3 Filter Node L3 Filter Node 100 Mb Switch Gb Switch To FCC 100 Mb Switch 100 Mbit Ethernet Gbit Ethernet RIP Interface RIP Interface D0 Online Event Monitoring Physical Data Flow Data Logger Data Logger RIP Interface RIP Interface Buffer Disk Collector / Router Collector / Router

7. Data Distributor Data Distributor EXAMINE L3 Filter Node L3 Filter Node Collector / Router Collector / Router L3 Filter Node L3 Filter Node Data Logger Data Logger Data Logger Data Logger Buffer Disk L3 Filter Node L3 Filter Node Collector / Router Collector / Router L3 Filter Node L3 Filter Node Flow Control No Flow Control EXAMINE Routing based on Stream ID Distribution based on Trigger type Buffer Disk To FCC RIP Interface RIP Interface To FCC RIP Interface RIP Interface D0 Online Event Monitoring Logical Data Flow

8. Monitoring Executables (Examines)  Detector performance  Physics Objects - e's  's jets Unpack raw data Reconstruct events Fill Histograms Provide event displays  Event selection via RCP file  Connect to DD with ACE  Apply algorithms to data  Interact with user interface Multiple Examines run on Linux PC's Joel Snow, D0 Collaboration, February 2000

9. DDDD InitializeInitialize Watchdogs for thread protection are separate ProcessEventsProcessEventsFinishFinish Repeat Event Buffer Assigned at Assigned at the Requests the Requests AbortAbort StartProcessingStartProcessing SelectExamineSelectExamine SelectInputSelectInput Pause/ResumePause/Resume StatusStatus StopStop GUI Process Control Nodes D0 Online Event Monitoring Processing Data and Message Flow Request Message Control Message Commentary Histogram Port Histogram Port. Data Flow Monitoring PC-Nodes DD Host ( Event display and other offline fwrk functions not added) Register Spawn an ExamineExecutable... EoRQueryEoRQuery ReadEvent Daq Initiateseparatethreads Offline Framework Flow Message Interface InterfaceMessage ProcessRegistryProcessRegistry Histogram Histogram EvtDSP EvtDSP

10. D0 Online Event Monitoring Histogram Control Flow ResetReset UpdateUpdate DisplayDisplay InputSelectInputSelect SaveSave Step Hists. Cycle Hists PrintPrint CompareCompare DDDD InitializeInitializeProcessEventsProcessEvents FinishFinish Repeat Event Buffer Assigned at Assigned at the Requests the Requests HistogramInterfaceHistogramInterface Request Message Control Message Commentary Histogram Port Initiate a thread Data Flow Monitoring PC-Nodes DD Host ROOTROOT GUI Histogram Control Nodes ProcessRegistry Register ReadEventDaqReadEventDaq

11. D0 Online Monitoring Interaction Sequence EventProcessing Inquiries & Process Cntrl Process Cntrl. GUI Process Registry Examine Main Thread GetEvt Thread D/D Other Threads Process Inquiry Inquiry Process List Start Process Process Start Examine Examine Initialize ( Start Threads ) Initialize ( Start Thread & assign buffer ) Initialize ( Connect to D/D & Transfer Selections ) Ready ( Connection made & buffer assigned ) & buffer assigned ) Ready ( Examine begun, Port #’s assigned ) Ready ( All threads begun, Port #’s assigned ) Port #’s assigned ) Ready( Threads begun ) Ready ( Thread begun and Connected to D/D ) Initialization Sequence Inquiries & Process Control (Pause, Resume, Reset, etc) Event Requests & Processing Events Status & Action Reports (Pause, Resume, Reset, etc) Event Request Event Transfer Reports Inquiries & Action End of Run Signal End of Process Inquiry End of Process Request Finish & Clean up Terminate Terminated Terminate Up Terminated Terminated Terminated TerminationSequence

12. GraphicalUserInterface Graphical User Interface  Control remote Examine  Obtain info from Examine histograms status/alarms  Checks process registry  Attach to existing Examine No control functions, observer mode Many may attach to single Examine  Start new Examine Full control functions, creator mode Joel Snow, D0 Collaboration, February 2000

13. GUI Functions ·Control  Start/Stop  Pause/Resume  Abort  Status  Dump Event  Display Event · Histogram  Display  Step  Compare  Update  Reset  Cycle  Save  Print Joel Snow, D0 Collaboration, February 2000

14. D0 Event Monitoring Process Control!!

15. ProcessControl

16. D0 ROOT GUI Histogram Control

17. Histogram Display A ROOT Histogram Window

18. Cycling Histograms A ROOT Histogram Window

19. ROOT's Use  Main analysis tool for Examines  Results in ROOT object format TFile, THxx, TNtuple  Examine - GUI communication TSocket, TServerSocket, TMessage  Synchronous - control & histograms  Asynchronous - alarms & messages  Idle loop accessed by inheriting from TApplication  GUI built from widget classes TGxxxx classes, TVirtualX Joel Snow, D0 Collaboration, February 2000

20. Conclusion  D0 online event monitoring system (D0OEMS) uses an asynchronous framework to reconstruct events, calulate physical quantities, and fill histograms  User interacts with framework through a GUI which provides information and control functionalities  Features of the ROOT framework have been successfully integrated into D0OEMS  While data taking is a year away, detector component commissioning is in progress. The D0OEMS described here is being used to verify the component performances  User response will guide future improvements  Hope to provide web based access of information to remote collaborators Joel Snow, D0 Collaboration, February 2000