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Getting Started

by John S. De Stefano Jr. last modified Dec 20, 2016 04:42 PM
Using the US ATLAS Computing Facility at BNL.
  • Apply for an computing account to gain access to the facility.
  • Disk space: New accounts are given an NFS home directory [/usatlas/u/<username>] with an initial quota of 2 GB, and an AFS [/afs/usatlas/users/<username>] directory with an initial quota of 400 MB. If you need more space, please submit a ticket to request an increase.
  • See our Kerberos page for information on authentication and changing your password.
  • In order to access RACF resources, you must first SSH into one of the gateways at
  • From a gateway, you can log into the Linux analysis farm nodes (, where XXXX is a four digit number; only a subset of these allow interactive logins). A complete list of all analysis nodes is also available.
  • To log into the farm nodes from the gateways, you can either use the rterm command, which will log you into the least loaded interactive node (run `rterm -h` on the gateway for more info), or log directly into the interactive node of your choice. For easy access to the interactive nodes, use the following:
    rterm acas+       # for an xterm window, or:
    rterm -i acas+    # no xterm
  • Access to the analysis farm is also available via the LSF and Condor batch systems, which is the only way to run jobs on the non-interactive nodes. As Condor is the preferred batch system at the RACF, users are encouraged to use (or migrate to) Condor, since LSF jobs get suspended when Condor jobs begin to execute on the same CPU resource. For information on using Condor, please look at the Condor Quick Start Guide. If you are unfamiliar with LSF, please see the Quick Start Guide and the list of queues that are currently configured. You must always specify the queue to you want to submit; if you are unsure, use either at_cas for regular jobs or at_cas_long for long-running jobs.
  • Use the HPSS system for archiving files.
  • Various grid services are provided by the RACF.
  • If you have any problems with the facility, please submit a ticket.
  • See information on using ATLAS software from the Physics Application Software (PAS) group.
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