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ATLAS Computing. Introduction Overview


Develop framework (Athena) through series of releases, leading to first fully ... This schedule is by no means final' or complete. ... – PowerPoint PPT presentation

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Title: ATLAS Computing. Introduction Overview

ATLAS Computing. Introduction Overview
  • Norman McCubbin (RAL)
  • Computing Co-ordinator

ATLAS Computing Introduction Overview
  • Organisation people/task matrix
  • Main milestones
  • Summary of major activities
  • Projectisation of Computing
  • schedule, PBS
  • effort holes software agreements
  • hardware resources
  • National Computing Board World-Wide Computing
  • MONARC CERN Review
  • Conclusions

Computing organization
Comp. Oversight Board
National Comp. Board
Comp. Steering Group
Technical Group
Event filter
QC group
Arch. team
Detector system
ATLAS Detector/Task matrix
Physics Co-ordinator F.Gianotti Chief
Architect D.Quarrie
ATLAS Computing Introduction Overview
  • Some aspects of organisation still need to be
  • software support librarian, Quality Assurance,
  • World-Wide Computing already have working-groups
    (WWC, Regional Centres, GRID, MONARC ). Need to
    develop some organisational structure to deliver
    Mock Data Challenges etc.

ATLAS Computing Introduction and Overview
  • The major schedule items (with indicative dates)
    for the next 2-3 years are
  • Develop framework (Athena) through series of
    releases, leading to first fully-functional
    version by end 01.
  • Profit from TestBeam requirements, starting this
  • Major effort to validate Geant4 for ATLAS, with
    simulation workshop Dec. 2000 and Physics
    workshop Spring September 2001.
  • Have first version of reconstruction software
    ready (start 01) for Event Filter analysis for
  • MDC0 100k event continuity test for end 01.
  • Chain (G4 simulation and ATLAS code) ready for
    MDC1 (0.1 PB) to start in 02. (Open issues
    how to trigger involvement of Regional Centres
  • Computing TDR deliver end 02. (Open issues
  • MDC2 First half 03. 10 of 1PByte. Must,
    inter alia, validate computing model. (Open
    issues how to trigger scale collaboration
    with other experiments.)

ATLAS Computing Introduction Overview
  • Simulation
  • major effort is focussed in Geant4 (G4) physics
    validation for ATLAS
  • very detailed studies (G4/G3/Test-Beam) are now
    in progress G4 looks promising but of course
    needs tuning/refining. ATLAS results presented at
    several conferences/work-shops.
  • Close and productive collaboration with G4 team
    (monthly meetings)
  • ATLAS G4-physics workshop Dec. 45
  • major goal is G4 good enough for Mock Data
    Challenge 0 (end 2001). G3 as insurance?

ATLAS Computing Introduction Overview
  • Reconstruction
  • first target is to have C versions of
    reconstruction working via framework (Athena) for
    end of this year muon code will be MuonBox
  • Lar code already available via Athena MuonBox
    and xKalman have been interfaced privately to
    Athena, some tidying still needed.
  • these versions of recon. codes will be used (on
    existing Geant3 data) for TDAQ TDR. (Maybe later
    versions, depending on TDAQ TDR date)

ATLAS Computing Introduction Overview
  • Projectisation of Computing
  • Scale, scope, duration, and cost of ATLAS
    computing project all argue for a greater formal
    projectisation of computing than has been done
    in previous experiments (LEP, HERA, UA1,2 , etc.)
  • Indeed, my time as Computing Co-ordinator has
    strengthened my conviction that this is not only
    desirable but essential.
  • Details of our planning etc. so far can be seen
    at http//
  • Considerable effort to harmonise with USA at PBS
    level to avoid duplication and confusion. (See
    presentations of Meinhard and Wenaus)
  • We have prepared a first version of a schedule,
    which includes the major milestones mentioned
    above, but also gives much much more detail.

ATLAS Computing Introduction Overview
  • This schedule is by no means final or complete.
    (e.g. World-wide computing not yet entered in
    detail, and dependencies need much more
    detail). But it does give significant detail
    through to end 2001, and is already proving
    valuable for Computing Steering Group (CSG) part
    of each (monthly) meeting is devoted to schedule
  • A first set of LHCC and ATLAS Exec. Board (EB)
    milestones has been defined. This list will
    surely grow.

ATLAS Computing Introduction Overview
  • PBS is used to estimate effort required to
    deliver the computing project.
  • It is clear that the entire project (including
    core software and detector-specific software)
    requires approx. 100 full-time-equivalent (fte)
    per year from now until (see next slide)
  • It is also clear that we have some urgent and
    obvious vacancies right now.
  • Hope that software agreements (see later)
    will help to fill these.

ATLAS Computing Introduction Overview
  • Core effort estimate (ftes)
  • 2000 2001 2002 2003
    2004 2005
  • sub-T O T A L (1-8) 30.2 33.4 30.6
    24.2 23.3 23.4
  • T O T A L (1-12) 34.6 47.2 46.6
    42.2 39.3 39.4
  • (1-8) includes framework, dBase, core
  • (1-12) adds in world-wide computing, GRID, MDCs.
  • N.B. above is requirement, we dont have it all!

ATLAS Computing Introduction Overview
  • It has also been recognised for some time that
    computing (hardware definitely, software
    probably) will require, and benefit from,
    Computing MoU.
  • This emphasises the point that CERN cannot
    provide the major share of these resources they
    have to come from the other institutes. (CERN
    will provide some, of course..)
  • More on the hardware side in a moment on the
    software side the main benefit (in my opinion) of
    an MoU is to commit institutes in the same way as
    they feel committed by detector MoU.

ATLAS Computing Introduction Overview
  • Since the signing of MoU is some way off, and
    because the whole idea is new for computing, we
    have been developing the idea of software
    agreements, which could, eventually, form part
    of Computing MoU.
  • The policy paper on software agreements has been
    approved by the National Computing Board, and by
    the ATLAS CB in June 2000.
  • We have just launched, through the NCB, a list of
    tasks which could be covered by core software
  • Idea of software agreement (swa) is to get formal
    institute commitment. Thus it helps ATLAS it may
    also help ATLAS members in arguing for resources
    in their institute.
  • Hope is to get first swa (Control Framework with
    USA) signed by end of the year.

ATLAS Computing Introduction Overview
  • On hardware resources, there is a lot of work
    going on, stimulated by the following (related)
  • as mentioned above, much of the money (and
    effort) for computing hardware and infrastructure
    will have to come from outside CERN scale is
    such that Funding Agencies will have to be asked
    officially for support
  • a possible model for World-Wide Computing was
    discussed already at the time of the ATLAS and
    CMS Computing TPs major computing centres
    (Regional Centres) in a few regions which act
    as computing hubs for their region(s). Thus you
    do not copy from CERN every time required data
    is copied to your Regional Centre once, etc.
  • This thinking has been elaborated in considerable
    detail in the MONARC project. ( Participation
    from all LHC experiments)
  • It is also now clear that estimates of resource
    requirement will be one of the most important
    outcomes of the CERN Review.

ATLAS Computing Introduction Overview
  • H.Hoffmann launched idea of CERN Review of LHC
    Computing in second half of 1999. Announced at
    Marseille workshop in September 99.
  • Aims
  • assess state of work and preparations in
    experiments and IT
  • provide input for Computing MoUs, which should be
    put in place in 2001 (?)
  • recommend actions and in particular common
    actions between experiments and IT Division that
    will help to achieve desired goals within
    existing resources
  • first draft of report December 2000 (?).
  • See H.Hoffmann talk yesterday(?).

ATLAS Computing Introduction Overview
  • Much of the subject matter discussed by CERN
    Review is also of prime concern to the ATLAS
    National Computing Board (NCB), Chairman Alois
    Putzer (Heidelberg)
  • Stimulated in part by CERN Review and various
    GRID activities, NCB has now formed w/groups
    which, as a first step, will gather information
    (whats going on) on GRID, Regional Centres
  • For several (related) reasons the whole topic of
    world-wide computing has, rightly, moved up the
    agenda in the last few months.
  • In ATLAS we have used a plausible estimate of
    event size (1MB) and trigger rate (100Hz) for
    several years. (As have CMS) Following the very
    detailed Physics (TDR) and Trigger (TP) studies,
    we have much more refined and understood
    estimates. But they are higher (270x2 at
    1033). This is being addressed, vigorously.

ATLAS Computing Introduction Overview
  • There has been a lot of progress since the
    DoE/NSF review in January
  • framework/architecture
  • Reconstruction Code
  • Simulation
  • organisational infrastructure (planning etc.)
  • And the USA contribution has been very
  • ATLAS Computing effort needs your continuing and
    ongoing support.