PWGC Summary of May, 1999 STAR Computing Meeting
This meeting included a two-day summary of the present state of STAR
software infrastructure and plans for future development on Monday and
Tuesday. In related sessions on Wednesday and Thursday several computing
tutorials were conducted and PWGs held individual and joint meetings.
On Tuesday evening a representative group from the PWGs met informally to
consider the state of STAR software as presented in the Monday-Tuesday
summary and to prioritize future work from a PWG perspective.
On Friday a wrap-up session was held in which the week's activities were
reviewed, the PWG informal meeting results were presented in the plenary
session, and a joint prioritization between BNL core computing and the PWGs
was conducted. These results are summarized below.
Consult the following page
on the computing web pages for additional material.
Thomas Ullrich and Tom Trainor for the PWG conveners
Near-future plans (from the web page):
- System stability - the working groups appreciate the great effort by
BNL core personnel and other collaboration members that has gone into
stabilizing the STAR software infrastructure. This achievement will
present to nonexperts and new users a software environment which gives
good return on their learning investment.
- Documentation - was recognized as of leading importance. Two types:
entry-level (getting started) for beginners and steady-state (user guide,
reference manual) to provide a continuing description of a complex system
that will certainly continue to evolve over the next year or two.
Robust and simplified entry-level documentation is an immediate action
This is accepted as a very high priority item by STAR core computing. Work
is underway, with cooperation between core computing and PWGs, especially
designated documentation editors from the PWGs (Peter Jacobs, Lanny Ray and
Gene Van Buren). The current bug report system should be used to report
incorrect or out-of-date documentation.
- Grand Challenge - Access to large data volumes on HPSS will probably not
be available via GC infra throughout this calendar year. Given the modest
data volumes to be produced in the summer run this may be tolerable. The
alternative is data volumes on local STAR disks with an ad-hoc file
This is accepted as a high-priority item by STAR core computing.
Extension of the MySQL data catalogue to a run/event database must be
completed as a top priority. Deployment of GC infra by end of year is also a
- Data Bases - this is a rapidly developing area, but much needs to be
done very quickly. PWGs need to be substantially involved in DB definition,
filling and QA. This is an immediate need in the next weeks. PWGs should
meet with DB developers at the earliest opportunity to learn what is planned
and what is needed from the physics community.
First meeting was held June 3 to identify existing DB info sources on the
web. Second meeting with DB experts occured June 8.
- QA - similar to DBs this is a rapidly developing area. Peter Ja. would
like another couple of weeks to formulate a general strategy. Immediate QA
activities in whatever form possible are essential, with gradual
replacement by a formal system over the next several months.
PWGs should begin an immediate intensive reexamination of present QA/monitor
histogram system managed by Kathy, interpret results and consider updates.
First pass at this is tentatively scheduled for June 10 meeting.
- Event visualization - There are several approaches presently available
and at various stages of development. There are obvious voids in STAR
visualization (e.g., on-line data monitoring by event display, more
comprehensive raw-data viewer). We do need to plan a comprehensive and
integrated visualization system to be available for the November run.
It is accepted that a critical-path need is on-line monitoring covered by
ROOT-based visualization within the general ROOT framework.
A priority need is to define and configure the required online displays. DSV
handling of STAR data in ROOT-file format is in development.
- Large-volume production on CRS - Production operations help will be
needed by the Fall run. It is neither possible nor desirable for this to be
entirely the responsibility of BNL core people. PWG members will have to
learn the details of CRS operation over the coming months.
- Raw data files - The current data acquisition scheme in which all physics triggers are
collected in one raw-data file for transmission to RCF is regarded as not
suitable for efficient STAR event reconstruction. This is especially true
peripheral-collisions events for which data volumes are minimal. One
would be to split the event types to separate files in the STAR `buffer
i.e., before they are transmitted to RCF. Another approach would be to
the decision to permit only one file type to be opened at a time to receive
STAR raw data by RCF, and to revisit this important issue with RCF
This is is an immediate action item.
- Disk organization - The current organization of the disk space available to STAR is regarded
as not sufficient. During the meeting we agreed to organize the disk
space as outlined below.
||type of data
||MDC2 data (~20GB)
||T3E production data sinking (Pavel)
||user scratch and Lidias data from daily/weekly tests
||actual data production (DSTs, histos, ...)
A mechanism has to be installed so that old and unused files are
automatically removed (either migrated to tape or deleted).
- extending data management tools (mysql DB + disk file management
+ HPSS file management + multi-component ROOT files) to provide
effective and scalable management of and access to data by
CRS and CAS production operations and end users
- management of CAS processing and data distribution both for mining
and individual physicist level analysis
- Grand Challenge deployment
- completion of the DB: integration of slow control as data source,
completion of online integration, implementation of DB as Geant
geometry data source, populating the DB for detectors other than
- completion of online and the online processing farm for monitoring
- improving QA tools and procedures, improving and better
integrating visualization tools
- reconstruction and analysis code development
directed at addressing QA results and year 1 code completeness
- extend and apply OO data model (StEvent) to reconstruction, so
new reconstruction development can work with StEvent