Russian Particle Accelerator Conference, – 03.10, 2008 Nikolay Malitsky Brookhaven National Laboratory Application, Status, and Direction EPICS'09 Workshop, Kobe, Japan

Outline Application: rationale, main Idea, DDS intro, benefits Status: EPICS-DDS structure, example Direction: new tasks, extensions,...

Rationale Distributed Front-Ends Physical Device Virtual Device Physical Device Online ModelMachine Virtual Accelerator Thin Application Thick Application Client Applications e.g. MMLT, others Middle Layer Servers... CA Two different interfaces Low-Level interface and protocol (EPICS, ADO,...)‏ High-Level interface and protocol (CDEV, CORBA,...)‏ Typical three-tier high level application environment

Standard Publish/Subscribe Specifications as candidates for high-level interface, [Summer 2008] MiddlewareLanguageData TypeData Content Filtering QoSComplexityYear CORBA Event Service C++, Java, …Generic and typed events no hard1997 CORBA Notification Service C++, Java, …Structured events yes hard~2000 Java Messaging Service (JMS)‏ Javafive types: text, map, bytes, stream, object messages filters are message properties noeasy~2000 High Level Application (HLA)‏ C++, Java, …Sequence of octets noyesTBD~2000 Data Distribution Service (DDS)‏ C++, Java, …User-specific data types yes easy2004 NSLS-II commissioning : 2013

DDS Data-Centric Publish Subscribe Model Topics of Typed Global Data Space:: a logical data space in which applications read and write data asynchronously, decoupled in space and time Publisher/Subscriber:: produce/consume information into/from Global Data Space QoS: reliability, predictability, availability, timeliness, etc. A.Corsaro. Advanced DDS Tutorial

DDS-Based Conceptual Design EPICS-DDS Main Idea: Start the implementation of the DDS specification in the form of the EPICS extension based on the Channel Access protocol IOC Distributed Front-Ends IOC Physical Device Virtual Device Physical Device IOC Online Model IOC Machine CAC IOC Virtual Accelerator Thin Application CAC Thick Application CAC Client Applications e.g. MMLT, others Middle Layer Servers... CA

Benefits Brought by DDS to EPICS The integration of these two technologies addresses five major tasks: First, DDS brings an industrial standard interface to the accelerator online environment allowing to decouple a variety of high-level applications and toolkits from the underlying low-level control systems, such as EPICS, TINE, TANGO, and others. Second, the DDS topic-oriented approach elevates the EPICS Channel Access protocol to the high-level applications replacing the additional RPC- like communication interfaces. Third, DDS creates a basis of Service-Oriented Architecture (SOA) promoting decoupling of the service interfaces from their project-oriented implementations [Nanbor Wang, Tech-X Corp.] Fourth, the DDS specification introduces some guidance for extending the EPICS infrastructure with the relevant set of quality of service. Finally, the DDS technology extends the EPICS run-time environment with the relational model creating a platform for adding relational queries and integration of full-scale Data Stream Management Systems (DSMS) for data stream processing and archiving.

EPICS-DDS Package EPICS-DDS Middleware: implementation of the OMG Data Distribution Service (DDS) interface based on the EPICS Channel Access (CA) protocol PV Data: generic hierarchical collection of FieldType's and PVField's including the PV Structure suggested by the Java IOC project Accelerator Model Interfaces (AMI): collection of the accelerator-specific interfaces and data containers based on the PV Structure Accelerator Model Servers (AMS): accelerator-specific middle layer based on the EPICS Portable CA Server (PCAS)‏ UI: EPICS-DDS script bindings including Python

EPICS-DDS Interface CA wrappers Serializers and Deserializers of PV Structures Compositions of Data Readers and Writers Basis class of User's Listeners Register of PV Structure-based User's types

AMS: Accelerator Model Servers PCAS-based Machine and Twiss Servers MachineMachine Machine Publisher Twiss Subscriber

TwissCalculatorCAS ITwissCalculator (Engine)‏ TwissPV TwissMachineSubscriber epicsThread StrengthReaderListener create start run Event from MachineServer Update Twiss Post Twiss on data available write into pipe select callBack read from pipe Post Twiss Event to Twiss Client fdManager TwissMachineReg installReg create Something beyond of the PCAS Tutorial l create pipe

UI: Collection of C++/script bindings SW SWIG-based approach. SWIG is Simplified Wrapper and Interface Generator used for C++ bindings with many scripting languages such as Python, Perl, PHP, Tcl, Ruby, etc. It works for most cases... void AccStrengthReaderListener::on_data_available( DDS::DataReader_ptr dr)‏ { EPICS::PVStructureReaderCAC* pvStructureReader = dynamic_cast (dr);... ::DDS::PVStructureSeq* data_values = 0; ::DDS::SampleInfoSeq* sample_infos = 0; long max_len = 0; pvStructureReader->read(data_values, sample_infos, max_len, sampleMask, viewMask, instanceMask); EPICS::AccStrengthData accStrengthData; for(unsigned int i=0; i length(); i++){ accStrengthData.setPVStructure(*((*data_values)[i])); std::cout << i << " : {"; std::cout << accStrengthData.getAccName() << ", "; std::cout << accStrengthData.getStrength() << ", "; std::cout << "}" << std::endl; } 1. callback 2. dynamic castt 3. inout and out arguments + our Python extension 1. Callable object 3. CORBA-compliant change in interface 2. Python-oriented adapter

Composite Example EPICS-DDS IOC Distributed Front-Ends IOC Physical Device Virtual Device Physical Device IOC IOC/CAS Machine CAC C++ DDS Subscriber Client Applications e.g. MMLT, others Middle Layer Servers... CA CAC TwissReaderListener C++ DDS Publisher CAC IOC/CAS Virtual Accelerator CAC IOC/CAS Twiss Calculator CAC Python

New Tasks (life after ICALEPCS' )‏ EPICS-DDS IOC Physical Device Virtual Device Physical Device IOC IOC/CAS Machine CAC C++ DDS Subscriber... CA CAC Client C++ DDS Publisher CAC IOC/CAS Virtual Accelerator CAC IOC/CAS Twiss Calculator CAC Matlab 1. Stony Brook, Computer Department ERL, Cornell IOC/CAS Optimization Web Server CAC 2. SBIR Phase II: Tech -X 3. ERL, Cornell NSLS-II, BNL 6. Configurable Virtual Accelerator 4. EPICS V4: PV Structure, Protocol, Java EPICS-DDS