Run II Computing: September 2005 Review Charge

 

Context

 

Run II Computing is now fully operational and thus far has worked well. In particular   the strategy of integrating computing resources from across the world seems to be working quite well. 

 

A year ago, the luminosity of the Tevatron had hit 1032 cm-2sec-1 once. The past year has seen a further increase of nearly 30%. One of the major components of future increases, electron cooling of the antiprotons in the Recycler, has been demonstrated at the level of an accelerator physics exercise. It is anticipated that full integration in the operations will follow over the course of the next year. The remaining gains to be won are in the actual antiproton production rate. This is not yet in and but the prospects for a further increase in Tevatron luminosity look good.

 

There are upgrades underway  to the experiments intended to deal with these increases but challenges to the computing will surely appear. For Dzero at least, handling the new upgrades will lead to, hopefully transient, perturbations to the reconstruction software.

 

Further, these challenges come as the end of the program appears on the horizon. There are pressures to consolidate effort and  to stabilize and improve the efficiency of the operations. These pressures appear across the board as we attempt manage a transition to life with the LHC.

 

This context has matured over the past year but the task we ask of this review is largely similar.

 

Computing and Funding Model

 

For some time the funding model for Run II computing has incorporated extensive use of remote processing of Monte Carlo data, reprocessing and analysis of collider data. We also have a goal to maximize the physics return for the installed experiment capability which leads to pressure for more processing and/or analysis capability. It remains important to understand the scope of this demand and how to properly manage it.

 

Challenges

 

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: -

 

1.      Scalability of the software with respect to incident luminosity.

2.      Scalability and performance of computing and data handling systems to meet the demands that more data will place on these systems.

3.      Scalability and reliability of systems to continue  support of  potentially large new demands for data movement into and out of the Fermilab site.

4.      The need to adapt the  computing models to increasingly rely   on common shared Grid facilities at Fermilab and at many off-site locations. 

5.      The need to manage all of the available resources, both on-site and off-site, in a way that  maintains high efficiency while maximizing physics  output. (At the time of writing of the charge, the Fermilab Director has instigated a task force to examine all aspects of the Tevatron Run II resource situation. We anticipate that this review will feed off the work of that task force and vice versa.)

 

 

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 following charge.

 

Consider and comment on:

 

1.      The status of each experiment in meeting the above challenges

2.      The status of the Computing Division planning, support, and infrastructure in helping to meet the challenges

3.      The adequacy of the anticipated resources  to meet these challenges and the adequacy of the new computing model on which this is based

4.      The status of the planning process for ongoing resources from Fermilab and experiment institutions for Run II computing and software infrastructure support, leading to updated MOUs. There should be some emphasis on understanding how the “end-game” might play over the next 4-6 years.

5.      Are there areas where application of modest increases in effort judiciously applied can lead to non-linear increases in efficacy?

6.      Are there likely to be major paradigm shifts in any area which could lead to significant modifications to the computing approach during the rest of the lives of the experiments (data taking to mid 2009, analysis for some time thereafter.)

 

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.