1. AliEn AliEn at OSC The ALICE distributed computing environment by Bjørn S. Nilsen The Ohio State University

2. AliEn Contents  Brief history.  Present status.  Capabilities.  Integration with other Grid activities.

3. AliEn Development time line 6/01Simple File Data-base proposed. 7/01Need to do ALICE Computing for PPR. 9/01Globus/EDG Far from ready to use. 11/01First AliEn prototype ready. 12/01First Simulation Production Runs done. 3/02Need to get access to production data. 6/02First general distributed computing environment ready.

4. AliEn AliEn World Wide Installations San Francisco Columbus

5. AliEn AliEn supplies " User Environment (Shell like environment). " Resource Broker (available computing and storage). " Meta data Catalog (input and output files). " Replica Manager (multiple copies of files). " Authentication (login services).

6. AliEn AliEn Computing Model User Submits job request. Central Server 1)Accepts Job Request. 2)Determines Resource locations. 3)OK’s Jobs to be run on sites. 4)Updates status and new file locations Remote Compute/Storage Site 1)Requests job to do. 2)Executes job received. 3)Returns job status. 4)Sends data to final storage. Remote Compute/Storage Site 1)Requests job to do. 2)Executes job received. 3)Returns job status. 4)Sends data to final storage. Remote Compute/Storage Site 1)Requests job to do. 2)Executes job received. 3)Returns job status. 4)Sends data to final storage. Remote Compute/Storage Site 1)Requests job to do. 2)Executes job received. 3)Returns job status. 4)Sends data to final storage.

7. AliEn Components Available in RPMs  AliEn-Base Contains external modules (more than 100, including Globus).  AliEn-Client Basic client functionality, needed to access LFNs.  AliEn-Server Serves Virtual Organization (one per).  AliEn-SE (Storage Element) Provides Mass Storage services at a site.  AliEn-CE (Compute Element) Provides Compute services at a site.  AliEn-GUI Optional package.  AliEn-Monitor Required by Server package to provide advanced RB features.  AliEn-Portal Provides AliEn Web site.  AliEn-Alice (Atlas) Provides specific virtual organizations with default settings.

8. AliEn C/C++ API (January)  Performance evaluation (ADC IV) Populating tags (January)  Extracting part of data stream for monitoring and partial reconstruction outside CERN (February) (=> postponed) GSI/Globus certificate authentication (March)  Adding new services Monitoring and exception handling (February = prototype)  Queue optimization (March) Support for arbitrary user jobs (April)  Disk pool/cache manager (January => postponed) ROOT interface (April)  Virtual datasets (May => August)  Modular “kernel” using POE (?) Use Condor ClassAds for resource description and matching(February) AliEn to do List