Summary of Apple's Xgrid cluster software and the steps we've taken to get it up and running at MIT.

Time	Talk	Presenter
14:00	Run VII purchase follow-up and discussion ( 00:10 ) 0 files	Jerome Lauret (BNL)
14:10	tripwire evaluation and configuration ( 00:10 ) 0 files	Mike DePhillips (BNL)
14:20	AOB ( 00:10 ) 0 files	All (All)

2006_mip-.pdf

2006_mip.txt

I plan on "Drupalizing" these pages soon, but for now here are links to Marco's slope calibration and Alex's MIP and Electron calibrations for the 2003 run:

Marco's tower slope calibration

Introduction

HPSS is software that manages petabytes of data on disk and robotic tape libraries. We will discuss in this section our observations as per the efficiency of accessing files in STAR as per a snapshot of the 2006 situation. It is clear that IO opptimizations has several components amongst which:

• Access pattern optimization (request ordering, ...)
• Optimization based on tape drive and technology capabilities
• Miscellaneous technology considerations
  (cards, interface, firmware and driver, RAID, disks, ...)
  
• HPSS disk cache optimizations
• COS and/or PVR optimization

However, several trend have already been the object of past research and we will point to some of those and compare to our situation rather than debating the obvious. Wewill try to keep a focus on measurements in our environment.

Tape drive and technology capabilities

A starting point would be to discuss the capabilities of the technologies involved and their maximum performance and limitations. In STAR, two technologies remain as per 1006/10:

• the 994B drives
• the LTO-3 drives

Access pattern optimization (request ordering, ...)

A first simple and immediate consideration is to minimize tape mount and dismount operations, causing latencies and therefore performance drops. Since we use the DataCarousel for most restore operations, let's summarize its features.

Time	Talk	Presenter
14:00	tripwire config, progress and time scale ( 00:10 ) 0 files	Mike DePhillips (BNL)
14:10	Run 6 data validation / new DB API ( 00:10 ) 0 files	Mike DePhillips
14:20	New node purchase, usage / status ( 00:10 ) 0 files	Wayne Betts (BNL)
14:30	SDAS enclave reminder (for this year) ( 00:10 ) 0 files	Jerome Lauret (BNL)
14:40	Opened discussion - BNL domain and SMS / operational needs & requirements ( 00:10 ) 0 files	All (All)
14:50	IRMIS progress ( 00:10 ) 0 files	Jiro Fujita (Creighton)
15:00	AOB ( 00:10 ) 0 files	All (All)

Runs used: 6013134 (13 Jan) - 6081062 (22 Mar)

The procedure for performing the relative calibration can be divided into 3 steps:

1. Create a histogram of the pedestal-subtracted ADC values for minimum-ionizing particles in each tower
2. Identify the working towers (those with a clearly identifiable MIP-peak)
3. Use the peak of each histogram together with the location of the tower in eta to calculate a new gain
4. Create new gain tables and rerun the data, this time looking for electrons
5. Use the electrons to establish an absolute energy scale for each eta-ring

Using Mike's code from the calibration of the 2004 data, an executable was created to run over the 62GeV CuCu data from Run 5, produce the 2400 histograms, and calculate a new gain for each tower. It was necessary to check these histograms by hand to identify the working towers. The output of the executable is available as a 200 page PDF file:

Originally posted 26 September 2005

Catalog query:
input URL="catalog:star.bnl.gov?production=P05if,tpc=1,emc=1,trgsetupname=ppProduction,filename~st_physics,filetype=daq_reco_mudst,storage=NFS" nFiles="all"

note: 3915/4240 = 92.3% of the available towers were able to be used in the calibration. Lists of bad/weird towers in the pp run are available by tower id:
bad_towers_20050914.txt
weirdtowers_20050914.txt

The relative calibration procedure for pp data is identical to the procedure we used to calibrate the barrel with CuCu data (described below). The difference between pp and CuCu lies in the electron calibration. In the pp data we were able to collect enough electrons on the west side to get an absolute calibration. On the east side we used the procedure that we had done for the west side in CuCu. We used a function that goes like 1/sin(theta) to fit the first 17 eta rings, extrapolated this function to the last three eta rings, and calculated the scale factors that we should get in that region. Here is a summary plot comparing the cucu and pp calibrations for the 2005 run:

(2005_comparison.pdf)

Originally posted 11 October 2005

Previously we had calibrated the BEMC using data from all triggers. We now have enough data to restrict ourselves to minimum-bias triggers. Additionally, we have implemented a cut that requires the pedestal-subtracted ADC value of neighboring towers to be less than twice the width of the pedestal. This cut does an excellent job of removing background, especially in the high-eta region:

Introduction

To treat many-particle events (pp and AuAu), we need to know which particle generated which cluster/point before evaluating the reconstructed clusters and points.  StEmcAssoc

Introduction
Transfers where either the source or target are on the Birmingham cluster. I am keeping a log of these as they come up. I don't do them too often so it will take a while to accumulate enough data points to discern any patterns…

Update:  New B/EEMC embedding framework from Wei-Ming Zhang currently in peer review

All calibration information is stored in the STAR database.  We have the following tables for BEMC calibrations:

• For the BTOW and BPRS detectors:
• St_emcCalib - this table contains absolute gain information for each channel
• St_emcPed - this table contains pedestal values for each channel
• St_emcGain - this table contains a gain correction factor vs. time for each channel (not currently used)

This database stores all BEMC trigger information such as trigger status, masks and pedestals used to obtain the high tower and patch sum information.  The database is updated online while taking data.  We have the following table formats:

These pages describe how to use the BEMC database.  There is a browser-based tool that you can use to view any and all BEMC tables available at:

Introduction:

The recalibration of the BEMC towers for Run 4 includes the following improvements:

Introduction

The final BTOW calibration for Run 5 offers the following improvements over previous database calibrations:

Immediate action items: