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ALMA Common Software Status and Development

ACS is a robust and well-tested software infrastructure based on the Component/Container paradigm, providing basic services for object-oriented distributed computing. It offers transparent remote object invocation, distributed error and alarm handling, and more. ACS is extensively used in ALMA and other projects.

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ALMA Common Software Status and Development

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  1. ALMA Common SoftwareStatus and Development G.Chiozzia, A.Caproniae, R.Ciramie,P.Di Marcantonioe,D.W.Fugated, S.Harringtonb, B.Jerama, M.Peskoc, M.Sekoranjac, H.Sommera, K.ZagarcaESO bNRAO cCosylab dU.Calgary eINAF-AOT gchiozzi@eso.org ICALEPCS 2005 - WE2.4-6I

  2. What is ACS? Where are we? Main features Platforms Highlights of the last two years Projects and community Conclusion Contents • Component/Container model • Event Handling and Notification Channel • Threading support • Real time • Bulk Data • Simulation • Alarm System • Task and parameters • GUIs • Benchmarking ALMA Common Software Status

  3. What is ACS? ACS is a software infrastructure for the development of distributed systems based on the Component/Container paradigm • common application framework and design patterns, not just libraries • well tested software that avoids duplication • make upgrades and maintenance reasonable • common development environment and tools ALMA Common Software Status

  4. Where are we? • Developed for ALMA and used by several other projects. • ACS is based on a kernel of software contributed by cosylab and developed for ANKA. Our collaboration started in Trieste at ICALEPCS 1999. • ½ of allocated development effort spent until now • Total allocated ~25 man years + additional external contribution (~10). • 9th release • Extensively used in the field: • ALMA Test Interferometer and labs • ALMA software integrations • Other projects ALMA Common Software Status

  5. Main Features • ACS provides the basic services needed for object oriented distributed computing. Among these: • Transparent remote object invocation • Object deployment and location based on a container/component model • Distributed error and alarm handling • Distributed logging • Distributed events • The ACS framework is based on CORBA and built on top of free CORBA implementations. ALMA Common Software Status

  6. Supported Platforms • Operating system: Linux, RH-E + other flavours • Real-time: RTAI and VxWorks • Languages: C++, JAVA, Python • CORBA middleware: TAO (& ACE) (C++), JacORB (Java), Omniorb (Python), CORBA services. • Embedded ACS Container: PC104, Debian, 300Mhz Geode, 256MB RAM, 256 MB flash (CosyLAB microIOC) ALMA Common Software Status

  7. Policy and License: LGPL • The strategy to provide common features to our users is: • Use as much as possible open-source tools, instead of implementing things. • Do not reinvent the wheel • Do not pay for licenses • Identify the best way to perform a certain task among the many possibilities • Wrap with convenience and unify APIs • ACS is distributed under LGPL license ALMA Common Software Status

  8. Highlights of the Last Two Years New in ACS for: • developers to use in their code: libraries, convenience classes, utilities to improve the quality of the code • test/integration/administrators, transparently from application code (i.e. in principle transparent to Component developers) ALMA Common Software Status

  9. Comp container Comp Component Container Evolution/Cleanup functional interface: observe() lifecycle interface: init() cleanUp() • Container Services • Full separation between Container and Container Services • Cleaner interfaces • Easier to replace Container implementation • The most important services provided now by the ContainerServices are… • Component life cycle • Plain instantiation of Components not sufficient • Standard lifecycle state machine introduced for the Container to manage Components container service interface getComponent(“CompB”); Logger getLogger(); ALMA Common Software Status

  10. Master Component • ALMA subsystems interact with the Executive. • Executive treat all in the same way. • Lifecycle for subsystems, not only components • Fits smoothly into acs concept: • each subsystem needs a mastercomponent • it is a component with a specific interface • ACS defines the underlying state machine • Implementation: • a generator (using open-architectureware) maps UML to state machines • generator creates convenience base classes • state machine has been refined in a couple of design iterations • The introduction of the Master Component has been very effective. • Cost of prototype generator not higher than cost of developing the MasterComponent in code ALMA Common Software Status

  11. Event Handling and Notification Channel • Events are widely used in ALMA for synchronization and asynchronous, *-to-* communication. • Decoupling of Consumers and Suppliers • Very easy interface: • Supplier classes • Consumer classes • Contract based on IDL data structures. • Strong naming conventions and checking tools • Administrative interface • Quality of service ALMA Common Software Status

  12. Threading Support • Many Components have a multi-threaded structure • Management of threads was a source of problems • Developed easy-to-use threading classes: • Override a run() method • Use the thread manager • Based on ACE Threads in C++, concurrent library in Java ALMA Common Software Status

  13. VxWorks → TICS Entire LCU in real-time OS ACS provides complete Container/Component in real-time environment Support will probably remain for other projects (VLT) RTAI → ALMA RT Kernel inside Linux Component not real-time ↔ small time-critical functions in Kernel. Less code in real-time, but more complex to debug ACS provides easy: Communication with kernel modules Logging from kernel modules Kernel module management A change in paradigm! Real-time Support ALMA Common Software Status

  14. Achieved Performance • Gigabit P2P Ethernet • BD throughput around 800 Mbits/s (~100 MB/s) requirements fulfilled • CORBA throughput around then 500 Mbit/s (~ 55 MB/s) • Estimated gain in the throughput around 30% Bulk Data Transfer • Requirements from the correlator: • 64 MB (megabyte)/sec • Based on CORBA A/V streaming service • TAO C++ implementation • Very easy interface, based on our use cases • No CORBA A/V visible See poster: PO1.032-6 ALMA Common Software Status

  15. Simulation • Why simulation? • Distributed development • Features or entire subsystems not yet available • Test a subsystem in isolation • Simulation of Components from IDL interface spec. • Dumb default or “intelligent” simulation See presentation: WE4A.2-5O ALMA Common Software Status

  16. Reuse the Laser Alarm Console ACS Component/Container replaces J2EE CERN Laser Reimplementation of Laser interfaces IDL interfaces replace EJB interfaces Keep the same API acsjms implements jms for ACS on top of Notification Channel ACS Alarm System: Laser Feasibility prototype to re-use CERN Laser Alarm System(TH2.3-7O) The challenge: reuse a complete subsystem/service in a verydifferent software infrastructure ALMA Common Software Status

  17. Tasks and Parameters • ACS is used in ALMA also as data reduction infrastructure framework • Requirement: data reduction to be started as a stand-alone process.A program which starts-up, performs processing and shuts down. • Implementation: • Stand alone executable • Static container • Works with and without ACS suite • Input parameters are complex data sets: • Parameter set definition (xml) • Parameter set instantiation (xml) • Validation • Parsing ALMA Common Software Status

  18. ACS Supports ABeans development with an Eclipse plug-in A LabView prototype has been implemented Some projects are using Qt GUIs Different projects and differentsubsystems have different requirements! ALMA Common Software Status

  19. Performance and Benchmarking • ACS has performance requirements to satisfy • Changes to code and upgrade of external libraries can affect performance • Created performance measurements and reporting framework • Performance of Component to Component communication, notification channel, logging system… http://www.eso.org/~almamgr/AlmaAcs/Performance/BenchmarkDoc/ ALMA Common Software Status

  20. ACS installations and projects ALMA Common Software Status

  21. OAN 30m (Spain) APEX (Chile) Sardinian Radio Telescope(Italy) ALMA(Chile) HPT Hexapod Telescope(Germany → Chile) ANKA (Germany) The ACS community ALMA Common Software Status

  22. ICALEPCS - 2nd ACS Workshop ALMA Common Software Status

  23. Conclusion • Core concepts very stable • In use in ALMA and other projects: we have been getting a lot of useful feedback • A lot of work to do: • Most packages available, but features incomplete • In particular scalability and performance issues. We know what to do. • Make easier the life of developers: abstract concepts, code generation (ACS code generation developed by community). Having a user’s base in addition to our main project has provided important feedback, cross-fertilization of concepts and ideas and contributed to software quality ALMA Common Software Status

  24. Questions (& Answers) http://www.eso.org/projects/alma/develop/acs ICALEPCS Papers ALMA Common Software Status

  25. Reserve slides ALMA Common Software Status

  26. Performance Average C++ throughput: 1500 event/s (100 bytes) Average C++ throughput: 3500 event/s (100 bytes) ALMA Common Software Status

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