1. Framework for Raw Data Thomas Kuhr Offline Week 29/06/2004

2. 2 Motivation Why do we need simulated raw data?  Reasonable estimate of data volume and structure for Computing Data Challenge  Development and verification of reconstruction code starting from raw data  Reconstruction of real data  Next Physics Data Challenge

3. 3 SDigits Overview Detector Trigger DAQRaw Data ClustersTracksESD DigitsSDigitsHits HLT SimulationReconstruction OnlineOffline Monte Carlo Real Data Particles

4. 4 Raw Data Format DDL Files: –One directory per event: rawN –One binary file per DDL: DET_DDLID.ddl –File contains DDL data header and payload  Equivalent to data sent over DDL DATE: –One date file with many events –Equipment and event headers added  Equivalent to DAQ output (without alimdc) Root: –One root file with many events  Equivalent to recorded raw data

5. 5 User Interface Run full simulation and write raw data for all detectors: AliSimulation sim; sim.SetWriteRawData(“ALL”); sim.Run(); Optional second argument: raw data file name (date or root) Shortcut method: sim.WriteRawData(“TRD PMD”,“raw.root”); Equivalent to: sim.WriteRawFiles(“TRD PMD”); sim.ConvertRawFilesToDate(“raw.date”); sim.ConvertDateToRoot(“raw.date”, “raw.root”);

6. 6 Implementation AliSimulation calls virtual method of detector: void AliModule::Digits2Raw(); Digits2Raw method: –Create one file per DDL: DET_DDLID.ddl –Write DDL data header ( AliRawDataHeader ) Set data size ( AliRawDataHeader.fSize ) Indicate valid data ( AliRawDataHeader.SetAttribute(0) ) –Write raw data of current event Order of channels? Raw data DDL files → DATE file: program dateStream (put it on afs?) DATE file → root file: program alimdc

7. 7 Status http://aliweb.cern.ch/people/cheshkov/rawdata.html

8. 8 Reading of Raw Data Separate two tasks: Reading of raw data (stored in different formats) into memory → Independent of content  Raw reader classes Interpretation of raw data → Specific to each detector  Raw stream classes

9. 9 AliRawReader Base class for reading raw data of one event Virtual methods: Bool_t ReadHeader(); Bool_t ReadNextData(UChar_t*& data); Bool_t ReadNextInt(UInt_t& data); Bool_t Reset(); void Select(Int_t detectorID, …); UInt_t GetType() const; Int_t GetDDLID() const; Int_t GetDataSize() const; … Derived classes: AliRawReaderFiles, AliRawReaderDate, AliRawReaderRoot

10. 10 AliDETRawStream Interpretation of detector specific raw data Iterator over digits AliDETRawStream(AliRawReader*); Bool_t Next(); Int_t GetSector() const; Int_t GetRow() const; Int_t GetPad() const; Int_t GetTime() const; Int_t GetSignal() const; Raw stream classes for TPC and ITS in RAW module, for TRD and PMD in detector modules

11. 11 Raw Data Reading Classes Ali Raw Rea der AliRawReaderFiles AliRawReaderDate AliRawReaderRoot AliTPCRawStream AliPMDRawStream AliDETRawStream TPC digits PMD digits DET digits TPC_0.ddlTRD_1024.ddlPMD_3072.ddl raw.date raw.root

12. 12 SDigits Reconstruction of Real Data Detector Trigger DAQRaw Data ClustersTracksESD DigitsSDigitsHits HLT SimulationReconstruction OnlineOffline Monte Carlo Real Data Particles

13. 13 Proposal: User Interface Use raw data DDL files in directory dir : AliReconstruction rec; rec.Run(“dir/”); Use DATE file raw.date : rec.Run(“raw.date”); Use root file raw.root (extension “.root ”): rec.Run(“raw.root”);

14. 14 Proposal: Implementation Extend virtual interface of AliReconstructor : void Reconstruct(AliRunLoader*, AliRawReader*) const; void FillESD(AliRunLoader*, AliRawReader*, AliESD*) const; Loop over events inside or outside Reconstruct method? Functionality of AliRawReader has to be extended for inside loop

15. 15 Open Questions galice.root file has to be created with -Loaders -Detector parameters / geometries -Magnetic field -AliRun object ? -…  Run database ?

16. 16 Summary Simulation of raw data is vital 3 formats of raw data: DDL files, DATE, root AliSimulation provides framework for raw data simulation Reading of raw data with AliRawReader and raw stream classes Framework for reconstruction of real data proposed Some open questions to be solved