1 The AliRoot framework, status and perspectives R.Brun, P.Buncic, F.Carminati, A.Morsch, F.Rademakers, K.Safarik for the ALICE Collaboration CHEP 2003 La Jolla, March 24-28, 2003

2CHEP 2003, La JollaMarch 27, 2003 online system multi-level trigger filter out background reduce data volume level 0 - special hardware 8 kHz (160 GB/sec) level 1 - embedded processors level 2 - PCs 200 Hz (4 GB/sec) 30 Hz (2.5 GB/sec) 30 Hz (1.25 GB/sec) data recording & offline analysis Alice collaboration Total weight10,000t Overall diameter 16.00m Overall length25m Magnetic Field0.4Tesla

3CHEP 2003, La JollaMarch 27, 2003 Strategic decision in 1998 Hits Zebra/RZ/FZ ROOT Framework kinematics in C++ Geometry in C++ Hits Digits ROOT Trees Geant3 Alice Geant3, PAW FORTRAN 129k binaries download 1M clicks per month 30k docs in 12 months 2.2k users in roottalk

4CHEP 2003, La JollaMarch 27, 2003 Root digit structures AliRoot evolution schema ROOT data visualisation Root tracks C++ macro Physics results Alice Offline Framework Root output file Root hits structures C++ macro C++ macro

5CHEP 2003, La JollaMarch 27, 2003 Framework AliRoot framework C++: 400kLOC + 225kLOC (generated) + macros: 77kLOC FORTRAN: 13kLOC (ALICE) + 914kLOC (external packages) Maintained on Linux (any version!), HP-UX, DEC Unix, Solaris Works also with Intel icc compiler Two packages to install (ROOT+AliRoot) + MC’s Less that 1 second to link (thanks to 37 shared libs) 1-click-away install: download and make (non-recursive makefile) AliEn 25kLOC of PERL5 (ALICE) ~2MLOC mostly PERL5 (opens source components) Installed on almost 50 sites by physicists >50 users develop AliRoot from detector groups 70% of code developed outside, 30% by the core Offline team

6CHEP 2003, La JollaMarch 27, 2003 AliRoot layout ROOT AliRoot STEER Virtual MC G3 G4 FLUKA HIJING MEVSIM PYTHIA6 PDF CRT EMCALZDC FMD ITS MUON PHOSPMDTRD TPC TOF STRUCT START RICH RALICE EVGEN HBTP HBTAN ISAJET AliEn

7CHEP 2003, La JollaMarch 27, 2003 Whiteboard Data Communication Class 1Class 2 Class 3 Class 4 Class 5Class 6 Class 7 Class 8

8CHEP 2003, La JollaMarch 27, 2003 The Virtual MC User Code VMC Geometrical Modeller G3 G3 transport G4 transport G4 FLUKA transport FLUKA Reconstruction Visualisation Geant3.tar.gz includes an upgraded Geant3 with a C++ interface Geant4_mc.tar.gz includes the TVirtualMC Geant4 interface classes Generators OPERA Neutrino oscillations, international collaboration CBM Future nucleus-nucleus collision program GSI, Darmstadt Considering of building simulation based on VMC Indicated as a technology of choice by the LHC Simulation Project

9CHEP 2003, La JollaMarch 27, 2003 ALICE 3 million volumes

10CHEP 2003, La JollaMarch 27, 2003 Performance & Checks DetectedNot detected

11CHEP 2003, La JollaMarch 27, 2003 COMMON /TRACKR/ AliMagF TVirtualMCStack TFluka TVirtualMCApplication FLUKAM CASCADE SOURCE MGDRAW ENDRAW MAGFLD

12CHEP 2003, La JollaMarch 27, 2003

13CHEP 2003, La JollaMarch 27, 2003 ALICE Physics Data Challenges Verify model and computing framework Reduce the “technological risk” Understand physics potentialities of the detector Prepare code for simulation, reconstruction and analysis Period (milestone) Fraction of final capacity (%)Physic objectives 06/01-12/011%Pp studies, TPC and ITS reconstruction 06/02-12/02 5% First test of the complete chain from simulation to analysis for the PPR. Simple analysis tools. Digits in ROOT format. 01/04-06/04 10% Compledte chain used for trigger studies. Prototype of analysis tools. Comparisons with parametrised MC. Simulated raw data. 01/06-06/06 20% Test of the final system for reconstruction and analysis.

14CHEP 2003, La JollaMarch 27, 2003 AliEn progress 32 (was 28) sites configured 5 (was 4) sites providing mass storage 12 production rounds jobs validated, 2428 failed (10%) Up to 450 concurrent jobs 0.5 operators Yerevan CERN Saclay Lyon Dubna Capetown, ZA Birmingham Cagliari NIKHEF GSI Catania Bologna Torino Padova IRB Kolkata, India OSU/OSC LBL/NERSC Merida Bari Nantes

15CHEP 2003, La JollaMarch 27, 2003 AliEn as a meta-GRID AliEn User Interface AliEn stackiVDGL stackEDG stack S.Bagnasco DataTAG

16CHEP 2003, La JollaMarch 27, 2003 AliEnFS & Distributed Analysis ******************************************* * * * W E L C O M E to R O O T * * * * Version 3.03/09 3 December 2002 * * * * You are welcome to visit our Web site * * * * * ******************************************* Compiled for linux with thread support. CINT/ROOT C/C++ Interpreter version , Oct Type ? for help. Commands must be C++ statements. Enclose multiple statements between { }. root [0]newanalysis->Submit(); Analysis Macro MSS CE merged Trees +Histograms ? Query for Input Data MSS VFS Kernel LUFS Kernel Space AliEnFS AliEn API User Space castor:// soap:// root:// /alien/ alice/atlas/ data/ prod/ mc/ a/b/ Linux File System MSS

17CHEP 2003, La JollaMarch 27, 2003 Parallel Analysis of Event Data root Remote PROOF Cluster proof TNetFile TFile Local PC $ root ana.C stdout/obj node1 node2 node3 node4 $ root root [0] tree.Process(“ana.C”) $ root root [0] tree.Process(“ana.C”) root [1] gROOT->Proof(“remote”) $ root root [0] tree->Process(“ana.C”) root [1] gROOT->Proof(“remote”) root [2] dset->Process(“ana.C”) ana.C proof proof = slave server proof proof = master server #proof.conf slave node1 slave node2 slave node3 slave node4 *.root TFile 32 Itanium II 2x1GHz, 2 GB RAM, 2x75GB 15K SCSI, Fast/GB Eth

18CHEP 2003, La JollaMarch 27, 2003 Software Development Process ALICE opted for a light core CERN offline team… Concentrate on framework, software distribution and maintenance …plus people from the collaboration GRID coordination (Torino), World Computing Model (Nantes), Detector Database (Warsaw) A development cycle adapted to ALICE has been elaborated Developers work on the most important feature at any moment A stable production version exists Collective ownership of the code Flexible release cycle and simple packaging and installation Micro-cycles happen continuously 2-3 macro-cycles per year Discussed & implemented at Off-line meetings and Code Reviews Corresponding to major code releases We have high-level milestones for technology and physics Computing Data Challenges test technology and integration DAQ – Off-line Physics Data Challenges test the Off-line from the user viewpoint

19CHEP 2003, La JollaMarch 27, 2003 AliRoot maintenance Regular release schedule One major release every six months One minor release (tag) every month Continuous maintenance and support Very few bugs in the production release because the development version is always available Emphasis on delivering production code Corrections, protections, code cleaning, geometry Nightly produced UML diagrams, code listing, coding rule violations, build and testsUML diagramscode listing, coding rule violationsbuild and tests One single repository with production and development coderepository

20CHEP 2003, La JollaMarch 27, 2003 ROOT, ALICE & LCG LCG is the LHC Computing Project The objective is to build the computing environment for LHC ALICE has lobbied strongly to base the LCG project on ROOT and AliEn The choice of the other experiments is to establish a client- provider relationship with ROOT While developing alternatives for some of existing ROOT elements or hiding them behind abstract interfaces And to use the result of GRID MiddleWare projects ALICE has expressed its worries Little time to develop and deploy a new system Duplication and dispersion of efforts Divergence with the rest of the HEP community ALICE will continue to develop its system And to provide basic technology, i.e. VMC and geometrical modeller … and it will try to collaborate with LCG wherever possible

21CHEP 2003, La JollaMarch 27, 2003 Conclusions ALICE has solutions that are evolving into a solid computing infrastructure Major decisions have been taken and users have adopted them Collaboration between physicists and computer scientists is excellent The tight integration with ROOT allows a fast prototyping and development cycle AliEn provides a complete GRID solution adapted to HEP needs and it allowed us large productions with very few people “in charge” Many ALICE-developed solutions have a high potential to be adopted by other experiments and become “common solutions”