Core Minutes 12/7/2004  

Present:    Joanne Bogart, Toby Burnett, David Chamont, James Chiang, Johann Cohen-Tanugi, Seth Digel, Richard Dubois, Warren Focke, Berrie Giebels, Navid Golpayegani, Tony Johnson , Heather Kelly, Michael Kuss, Matt Langston, Francesco Longo, Chuck Patterson, James Peachey, Dirk Petry, Leon Rochester, Tom Stephens, Tracy Usher

• G4 news: (Francesco, Tracy) [Many thanks to Tracy for filling me in on what I mostly didn't hear. Any remaining inaccuracies are all mine. ed.] The new GR release (v5r0p1) with new G4 appears to run much faster than GR v4r7. See the last slide of the presentation given at the Analysis Group meeting. See also some statistics that Toby gathered. [however it now seems likely that the build of old G4 used by v4r7 is debug/non-optimized and the new build for v5r0p1 is optimized, which could account for much of the huge difference].

  The new G4 calculates effects of delta ray production and ionization energy loss differently, which probably accounts for the differences we McPositionHits in tracker and ACD: fewer with low deposited energy; more with higher deposited energy. Francesco was able to reproduce the GR v4r7 System Test distributions by using old G4 versions of relative routines. They plan to implement a switch in G4Generator so we can use either version, similar to what was done for multiple scattering.

• New RM: (Navid) It's well on its way! See his status page for a terse description of essential elements. Output of operations goes into a database, to serve as input for the front end. The critical pieces
  • processor to handle scheduling
  • batch submission
  • application operations like compile
  have all been tested individually and, as of yesterday, together. What's left to do: some of the more peripheral functionality, such as creating Doxygen, and the full-featured front end [first draft just seeing the light this afternoon.  Log in using SLAC unix count and click on Release Manager].

  New RM should have accumulated old RM functionality, more or less, in about 3 weeks. Then would be the time to start serious work on RM for Windows. How this is done is partly dependent on status of LSF for Windows. Navid would prefer to use it if possible, rather than writing what amounts to our own batch system for Windows. (Joanne) Marco and Riccardo have agreed to improvements to MRcmt (callable build functionality on Windows..MRvmct without the "v") as needed.

• Ban on moving tags: (Richard, Navid) Moving or deleting tags confuses CVS history for human browsers, but it also can cause problems for the Release Manager and hence for the Installer, since it depends on Release Manager. Seems best to disallow these operations altogether for normal users. Navid wrote a little script which will prevent anyone except user glast from moving and deleting tags. Although it is a bit unfortunate that certain clearly harmless changes, such as updates to documentation, will always result in a new tag with this script in place, consensus was that it's worth it to avoid the very occasional but also very unpleasant problems we've had when tags are moved. Navid will talk to Pat about incorporating the script, probably today, and will send an announcement when it is in place.
• No more IExternal open season: (Richard) Some time ago Navid took responsibility for IExternal and its subpackages. Proper maintenance of it is crucial for correct operation of the Installer. Please remember to consult with him before making any changes
• Doubles or floats (Leon) Discussion was to be continued this week [..but wasn't. Try again next week?]

∫ Flight(w, ..) dw

• EM tag imminent: (Heather) Head of EM passes all unit tests (Johann, Joanne tracked down CRflux problem). It's based on GR v4r7 so includes the new Xerces. Would be nice to pick of the latest LDF. May also want Riccardo's latest HepRep packages, if OKed by Anders. When the tag is made Navid will build optimized binaries and Julie will start up System Tests.
• About timestamps: (Heather) There are two in LDF data. The original one (seconds + nanoseconds since base time of Jan. 1 1970) is not necessarily unique, so a second set of words were added which provide more precision. They're known as upper and lower PPC words. They can be used in conjunction with the absolute time to construct a unique timestamp for each event.  However, when doing so, the result need not increase monotonically with event number for events whose original timestamps are identical. This can cause problems for TriggerAlg when it attempts to calculate deadtime. One solution would be to put the deadtime calculation somewhere else, where it could more easily be turned off in case the input is real instrument data.
• Release controls on the horizon: (Richard) Soon, perhaps as early as immediately after imminent EM tag, changes to production EM will have to go through the newly-instituted Change Control Board. We have to be able to move quickly as we discover new "features" in hardware or software, but we also need independent oversight. For now the release control applies only to the EM container, not to GlastRelease.

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J. Bogart Last Modified: 01-Jun-2010 15:45:10 -0700