Run II Computing: Draft of September 2004 Review Charge
Run II Computing is now fully operational and seems to be working quite well. Each experiment’s software is now fairly mature as are the tools they rely on such as C++ libraries, GEANT3, ROOT, frameworks, Event Data Model and I/O packages and software development and distribution environments. There are a growing number of active sites outside of Fermilab with computing resources available for one or more of MC production, processing of data, or analysis of data. The “service level” to the experiment of such off-site resources may vary greatly and range from a highly available professionally managed computing center, to a well run when needed (e.g. for reprocessing) physics department cluster, to a site able to support only their local community, and even to a site whose net contribution might be negative because of the large support burden they place on others.
Over the course of the past year, the luminosity of the Tevatron has grown such that in one recent store it exceeded 1032 cm-2sec-1. We might expect that the mean number of interactions per crossing and hence the occupancies might lead to stresses in the reconstruction and other effects.
Computing and Funding Model
The computing and funding models for Run II computing no longer assure adequate computing resources based at Fermilab for all processing, reprocessing of data and the generous level of computing sought for analysis. This is due to expanded experiment requirements in one or more of the categories of data rate/volume, amount of reprocessing, cpu usage for reconstruction programs, cpu usage for analysis programs or I/O needs for analysis. In particular the ability to write data at an increased rate has created windows of opportunity to enhance the physics output of the experiments. In each case, the Physics Advisory Committee encouraged the eperiments to seek increased resources beyond those available from Fermilab to analysis these extra data.
Although Run II computing and software activities are in an “Operations” phase there is clearly still much work to do and a number of challenges are present: -
Preparation for Review and Charge
The Experiments and the Computing Division have been asked to organize a series of presentations that will assist the review committee to respond to the the following charge.
Consider and comment on:
The committee is asked to present its findings, comments, and, where necessary, its recommendations, in order to help both the experiments and the Laboratory to meet the challenges above and to note any other challenges or concerns that they uncover in the course of the review.