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Minutes of the July 1 Offline Meeting



They are posted at 
http://www.jlab.org/Hall-D/software/wiki/index.php/July_1%2C_2009_Software 
and attached as text.

Minutes of the July 1, 2009 Offline Meeting

   Present:
     * Indiana: Matt Shepherd
     * JLab:  Eugene  Chudakov,  Mark Ito (chair), Alexander Somov, Simon
       Talyor, Elliott Wolin, Beni Zihlmann


Work disk

   Mark  shared  what he has learned recently about the [35]new work disk
   quota system at the Lab. It has a new "shared" space feature which can
   make  it  appear  that  a  particular  partition  is changing its size
   dynamically.

Software tag policy--when to modify the tag

   Mark led the discussion. From time to time, we are tempted to modify a
   tagged  release  when  a  bug  fix  is found, post-tagging. What to do
   depends  on balancing the desire to have a tag have a time-independent
   meaning  and  the desire to fix something that is broken when that fix
   requires  only  a  very  small change. So far we have left this to the
   judgment  of  the person maintaining the tag. There was a consensus on
   continuing with this practice.

Removing 2-GB-file-size limit

   David  led  us  through his [38]email message describing the change to
   the make system to fix the [39]limitation on HDGeant output file size.
   The change was done by adding the switch in one place in one file.

DRootGeom changes--multi-threading and ROOT

   David  showed  some  [41]slides describing the problem and options for
   dealing  with  thread  safety and the DRootGeom class. There are still
   some  kinks  to  work  out  with  the  table method. More on this next
   meeting.

Magnetic Field Documentation Webpage

   David  led  us through the issues documented on [43]this page. He will
   note on the page the appropriate use of the -Z0 switch.

Proposed changes to mcsmear

   We  discussed  the  issues  raised  in the [45]recent email discussion
   about  an  intermediate  stage between HDGeant and reconstruction that
   would  add random detector effects and create appropriate HDDM output.
   Matt  pointed  out  that  the structure of the smeared hits is in some
   cases  much  different  than  the  structure of the hits coming out of
   HDGeant.  For  example  the  BCAL  hits have the energy deposited in a
   module  as  they come out of HDGeant, but not the detector response at
   each  end. There is no place in the data model for this information at
   present.  mcsmear  remains  the  leading  candidate for providing this
   function.  David will take the lead in studying the changes this would
   require.

Hall D Unix groups

   Elliott  led  us  through [47]his proposal for re-arranging our set of
   Unix  groups  at JLab. We agreed that he should go ahead and implement
   this  with  IT  Division.  Eugene noted that the newgrp command can be
   used  to  create  a  new shell with the default group of one's choice.
   Elliott  also  mentioned  that  the  directory mode bits can be set to
   insure that all files created in that directory belong to same group.

Tracking removed from HDGeant

   David  led us through [49]his email announcing this change. This means
   that  we are now running with the straight-line approximation within a
   straw  for  calculating  the  drift distance in the CDC. This error is
   small compared with our position resolution.

Action Item Review

   Sascha  suggested that someone fix the [51]not-a-number problem in the
   BCAL cluster code.

   Mark  will  go  through [52]the list and mark done items as done. Next
   time we will discuss the [53]task list.

   New action items:
    1. Draft a policy on when to generate new hdparsim efficiencies. -> ?
    2. DRootGeom  allegedly  gets recompiled even if the geometry has not
       changed when a re-make is done. -> David
    3. Review action item list and cross out items that are done. -> Mark
    4. Further study on how to modify mcsmear -> David
    5. Document use of -Z0 options on magnetic field web page. -> David
    6. Sascha will contact Blake about the nan problem. -> Sascha


Agenda items for next time

    1. Group disk usage (work and cache for that matter): all
    2. Serializing ROOT objects and transfering them with cMsg: Elliott
     _________________________________________________________________

   Recorded by --[55]Marki 11:02, 2 July 2009 (EDT)

   Retrieved from
   http://www.jlab.org/Hall-D/software/wiki/index.php/July_1%2C_2009_Software

References

  35. http://www.jlab.org/Hall-D/software/wiki/index.php/JLab_Work_Disk_Quotas
  38. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00922.html
  39. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00918.html
  41. http://www.jlab.org/Hall-D/software/wiki/images/5/51/20090701_material_map.pdf
  43. http://www.jlab.org/Hall-D/software/wiki/index.php/Magnetic_Field_Maps_for_Solenoid
  45. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00925.html
  47. http://www.jlab.org/Hall-D/software/wiki/index.php/Hall_D_Unix_groups_discussion
  49. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00927.html
  51. http://www.jlab.org/ccc/mail_archives/HALLD/halld-offline/msg00929.html
  52. http://www.jlab.org/Hall-D/software/wiki/index.php/Action_Items_From_Hall-D_Software_Meetings
  53. http://www.jlab.org/Hall-D/software/Software_tasks.php
  55. http://www.jlab.org/Hall-D/software/wiki/index.php/User:Marki