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Note: This page contains sample records for the topic "last-modified 26-feb-1995 posting-frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Last Modified 1/11/13 Location and Institution ARGENTINA -CORDOBA  

E-Print Network [OSTI]

Last Modified 1/11/13 Location and Institution ARGENTINA - CORDOBA UNIVERSIDAD Requirements Students holding a U.S. Passport may enter Argentina as a tourist. You a "Student Visa" after your arrival in Argentina. Contact consulate for specific

Galles, David

2

Boot Camp: System Requirements for Microsoft Windows Last Modified: June 17, 2008  

E-Print Network [OSTI]

Boot Camp: System Requirements for Microsoft Windows · Last Modified: June 17, 2008 · Article: HT1899 · Old Article: 306538 Summary Apple's Boot Camp software, included with Mac OS X 10.5 Leopard. System requirements To use Boot Camp with Mac OS X 10.5 you need the following: · An Intel-based Mac

Papautsky, Ian

3

The NWB Tool Basic Tutorial: Getting Started Last Modified: February 5, 2008 1  

E-Print Network [OSTI]

The NWB Tool Basic Tutorial: Getting Started Last Modified: February 5, 2008 1 The NWB Tool Basic Tutorial: Getting Started Goals This tutorial introduces the NWB tool. You will learn how to perform Tool After downloading the NWB Tool for your specific operating system from http

Indiana University

4

Last Modified: 20Oct10 ARRA CONTRACT AWARD  

E-Print Network [OSTI]

Partnering Workforce Training Programs: Fresno Regional Workforce Investment Board Fresno County Economic energy efficiency retrofits in the Fresno and Kern county region. The FRCRR Program will provide no-cost efficiency to a home. To ensure program success, FRCRR will collaborate with local workforce investment

5

Date Last Modified: 2/08 (AA) PROGRESS MONITOR  

E-Print Network [OSTI]

.00 Psychology of Learning (strongly preferred) OR 3 791.03 Special Topics: Learning & Behavior Analysis 3 2 ORGANIZATIONAL BEHAVIOR MANAGEMENT: 791.03 Special Topics: Organizational Behavior Mgmt 3 MORE ELECTIVES: 730

Johnson Jr.,, Ray

6

Public Report Last Modified: 03/25/2013  

E-Print Network [OSTI]

.12 Variance 0.75 Standard Deviation 0.87 Total Responses 266 #12;3. 7. Does the President have your confidence

Dasgupta, Dipankar

7

Curriculum Vitae for Hanzhi Lin Last modified: 3rd  

E-Print Network [OSTI]

cyclonic eddy analyses on the largest macroalgal bloom in the world. Environmental Science and Technology Qin S.* , H. Lin* , P. JIANG. Advances in genetic engineering of marine algae. Biotechnology Advances

8

Candidacy Exams for Chemistry Graduate Students last modified 10/28/2011  

E-Print Network [OSTI]

, you should consult with T. S. Dibble 10/28/2011 1 #12;the Chair or your Major Professor, unless and facts of your field of study and understand how to apply those concepts in the scientific process. More

Chatterjee, Avik P.

9

WORKING DRAFT Last Modified 7/13/2014 9:34 PM Pacific Standard Time  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism inS-4500IIVasudhaSurface.Laboratory30, 2014WIPP's ScottWNClASSIflfO

10

Last Modified 2/1/13 Location and Institution SOUTH AFRICA-CAPE TOWN: UNIVERSITY OF CAPETOWN  

E-Print Network [OSTI]

Science, Gender Issues, Legal Studies, African Languages and Literature, History, Cinema, and others. For complete course offerings visit: http

Galles, David

11

2012 M. Scott Shell 1/16 last modified 5/29/2012 Visualizing molecular simulations ChE210D  

E-Print Network [OSTI]

program UCSF Chimera. Chimera comes preloaded with many helpful tools for analyzing results and making trajectory files that Chimera can read. This script can easily be incorporated into your Python simulation code, and is available on the course website. Installation To install Chimera, download the latest

Shell, M. Scott

12

Cedarville School District Retrofit of Heating and Cooling Systems...  

Open Energy Info (EERE)

Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Cedarville...

13

State Geological Survey Contributions to NGDS Data Development...  

Open Energy Info (EERE)

Contributions to NGDS Data Development, Collection and Maintenance Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title State Geological...

14

Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Document Name Sort items in descending order Object Created Object Last Modified NRC Concrete Meeting Busby NRC Concrete Meeting Busby LightWaterReactorSus...

15

Optimization of hybrid-water/air-cooled condenser in an enhanced...  

Open Energy Info (EERE)

hybrid-waterair-cooled condenser in an enhanced turbine geothermal ORC system Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title...

16

Index of /~lipman/Spain  

E-Print Network [OSTI]

Index of /~lipman/Spain. [ICO], Name Last modified Size Description. [DIR], Parent Directory, -. [ ], 1. Derived_categories_and_functors.pdf, 22-Feb-2009 04:

17

Merging High Resolution Geophysical and Geochemical Surveys to...  

Open Energy Info (EERE)

Buttes, Oregon Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Merging High Resolution Geophysical and Geochemical Surveys to Reduce...

18

Agenda | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Separations Research Workshop Agenda Postworkshop Reference Edition Last Modified May 18, 1999 Note that the titles and abstracts of presentations may be found by clicking on...

19

Microhole Arrays Drilled With Advanced Abrasive Slurry Jet Technology...  

Open Energy Info (EERE)

Arrays Drilled With Advanced Abrasive Slurry Jet Technology To Efficiently Exploit Enhanced Geothermal Systems Geothermal Project Jump to: navigation, search Last modified on July...

20

Guidelines | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Requirements Conferences Last modified: 10232013 6:17:49 PM Share Page Share with Facebook Facebook External link Share with Twitter Twitter External link Share with Google...

Note: This page contains sample records for the topic "last-modified 26-feb-1995 posting-frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Large Scale GSHP as Alternative Energy for American Farmers Geothermal...  

Open Energy Info (EERE)

Scale GSHP as Alternative Energy for American Farmers Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Large Scale GSHP as Alternative...

22

Index of /~santos/research/nuclear  

E-Print Network [OSTI]

Feb 28, 2013 ... Index of /~santos/research/nuclear. [ICO], Name Last modified Size Description. [DIR], Parent Directory, -. [ ], co2_monitoring.pdf...

23

Innovative & Novel Computational Impact on Theory & Experiement...  

Office of Science (SC) Website

Sheets External link 2015 Incite Announcement External link DOE Leadership Computing Web Site External link Last modified: 122015 4:09:21 PM Share Page Share with Facebook...

24

Energy-Efficiency-Related Conference Papers and Workshop Summarys  

U.S. Energy Information Administration (EIA) Indexed Site

Home > Households, Buildings & Industry > Energy Efficiency > Conference Papers Conference Papers Page Last Modified: September 2007 The Growth in Electricity Demand in U.S....

25

Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

>> Document Name Sort items in descending order Object Created Object Last Modified Brownfield Nuclear Power Plant Siting Report.pdf Brownfield Nuclear Power Plant Siting...

26

Index of /~wilker/misc/Electronics  

E-Print Network [OSTI]

Index of /~wilker/misc/Electronics. [ICO], Name Last modified Size Description. [DIR], Parent Directory, -. [ ], dram.pdf, 11-Sep-1998 23:10, 124K. [ ]...

27

Detachment Faulting and Geothermal Resources - An Innovative...  

Open Energy Info (EERE)

Resources - An Innovative Integrated Geological and Geophysical Investigation in Fish Lake Valley, Nevada Geothermal Project Jump to: navigation, search Last modified on...

28

Development of New Biphasic Metal Organic Working Fluids for...  

Open Energy Info (EERE)

Biphasic Metal Organic Working Fluids for Subcritical Geothermal Systems Geothermal Lab Call Project Jump to: navigation, search Last modified on July 22, 2011. Project Title...

29

Blind Geothermal System Exploration in Active Volcanic Environments...  

Open Energy Info (EERE)

and Geochemical Surveys in Overt and Subtle Volcanic Systems, Hawaii and Maui Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title...

30

Physiologist's Friend Chip User and Demonstration Guide The Physiologist's Friend Chip (http://www.ini.unizh.ch/~tobi/friend/chip) is a neuromorphic analog  

E-Print Network [OSTI]

Physiologist's Friend Chip User and Demonstration Guide The Physiologist's Friend Chip (http://www.ini materials and antistatic bag for traveling. Last modified 5/14/2009 See http://www.ini

Delbruck, Tobi

31

News - DOE Directives, Delegations, and Requirements  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Nuclear Explosive and Weapon Surety Program - Read More... NEW - DOE O 422.1 Admin Chg 2, Conduct of Operations - by Diane Johnson - last modified Jan 05, 2015 03:39 PM The...

32

Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sort items in descending order Object Created Object Last Modified 12-9051191-001 NGNP Hydro. Prod. Preconc. Design Studies Rpt.pdf 12-9051191-001 NGNP Hydro. Prod. Preconc....

33

file://C:\\Documents and Settings\\bh5\\My Documents\\Energy Effici  

Gasoline and Diesel Fuel Update (EIA)

5a Page Last Modified: May 2010 Table 5a. Economic and Physical Indicators for the Forest Products Industry, 1998, 2002, and 2006 (NAICS 321 and NAICS 322) Notes: 1. Deflated using...

34

file://C:\\Documents and Settings\\bh5\\My Documents\\Energy Effici  

Gasoline and Diesel Fuel Update (EIA)

f Released Date: May 2006 Page Last Modified: April 2010 Table 5f. Economic Indicators 1 for the Metalcasting Industry (NAICS 3315), 1998, 2002, and 2006 Notes: 1. Physical...

35

file://C:\\Documents and Settings\\bh5\\My Documents\\Energy Effici  

Gasoline and Diesel Fuel Update (EIA)

Trend Data, 1998, 2002, and 2006 > Table 5c Page Last Modified: May 2010 Table 5c. Economic and Physical Indicators for the Aluminum Industry (NAICS 3313), 1998, 2002, and 2006...

36

file://C:\\Documents and Settings\\bh5\\My Documents\\Energy Effici  

Gasoline and Diesel Fuel Update (EIA)

b Page Last Modified: May 2010 Table 5b. Economic and Physical Indicators for the Petroleum Industry (NAICS 324), 1998, 2002, and 2006 Notes: 1. Deflated using BEA's chain-type...

37

file://C:\\Documents and Settings\\bh5\\My Documents\\Energy Effici  

Gasoline and Diesel Fuel Update (EIA)

e Page Last Modified: May 2010 Table 5e. Economic and Physical Indicators for the Steel Industry, 1998, 2002, and 2006 Notes: 1. Includes iron and steel mills and...

38

Confidentiality of Research Proposals and Peer Reviews | U.S...  

Office of Science (SC) Website

under FOIA or other laws. Last modified: 3182013 10:33:27 AM Share Page Share with Facebook Facebook External link Share with Twitter Twitter External link Share with Google...

39

Einstein's Dream of Unified Forces - extra dimensions | U.S....  

Office of Science (SC) Website

of these deep connections. Last modified: 3182013 10:32:55 AM Share Page Share with Facebook Facebook External link Share with Twitter Twitter External link Share with Google...

40

Review and Selection of Research Projects | U.S. DOE Office of...  

Office of Science (SC) Website

performers of the work. Last modified: 3182013 10:33:28 AM Share Page Share with Facebook Facebook External link Share with Twitter Twitter External link Share with Google...

Note: This page contains sample records for the topic "last-modified 26-feb-1995 posting-frequency" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

A Geothermal District-Heating System and Alternative Energy Research...  

Open Energy Info (EERE)

District-Heating System and Alternative Energy Research Park on the NM Tech Campus Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title A...

42

Top500 | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Leadership Computing Facility (OLCF) Top500 Print Text Size: A A A FeedbackShare Page (Click here to go back to the ASCR OLCF page) TOP500 Web Site Last modified: 3152013 5:36:58...

43

New User's Intro to Computer Science Computing Resources Page: 1 New User's Intro to Computer Science Computing Resources.  

E-Print Network [OSTI]

New User's Intro to Computer Science Computing Resources Page: 1 New User's Intro to Computer Science Computing Resources. By Hanz Makmur Last modified: Jan 20, 2010 Table of Contents Things you need to start ________________________________________________________ 2 I. Getting Access to Resources

44

SimpleMonitorUSBXPress User Guide Tobi Delbruck, tobi@ini.phys.ethz.ch  

E-Print Network [OSTI]

SimpleMonitorUSBXPress User Guide Tobi Delbruck, tobi@ini.phys.ethz.ch Allows monitoring AER over at the University of Sevilla and the second by Tobi Delbruck at INI in Zurich. The firmware and host code is written. Last modified 8/20/2005 Under subversion https://svn.ini.unizh.ch/repos/avlsi/CAVIAR/wp5/USBAER

Delbruck, Tobi

45

STANDARD OPERATING PROCEDURES Annual Site Maintenance  

E-Print Network [OSTI]

IMPROVE STANDARD OPERATING PROCEDURES SOP 226 Annual Site Maintenance Date Last Modified Modified This standard operating procedure (SOP) describes the procedures for annual maintenance of equipment Sampler Operation Manual #12;SOP 226: Annual Site Maintenance 3 1.0 PURPOSE AND APPLICABILITY

Fischer, Emily V.

46

STANDARD OPERATING PROCEDURES Site Selection  

E-Print Network [OSTI]

IMPROVE STANDARD OPERATING PROCEDURES SOP 126 Site Selection Date Last Modified Modified by: 09 References none #12;SOP 126: Site Selection 3 1.0 PURPOSE AND APPLICABILITY This standard operating procedure field conditions, and for ease of operation and maintenance. IMPROVE aerosol samplers are generally

Fischer, Emily V.

47

Nuclear Engineering A Guide for  

E-Print Network [OSTI]

Nuclear Engineering A Guide for Undergraduate Majors Last modified Fall 2014 This guide applies-7451, Internet: www.engr.wisc.edu/ep/ #12;1 Introduction The Nuclear Engineering Program is administered to provide Nuclear Engineering undergraduate students with information that will facilitate their studies

Schulte, Mike

48

NAME/TEAM: ______________________________________ FTIR postlab -1  

E-Print Network [OSTI]

Spectroscopy Postlab Last modified: June 17, 2014 1) Summarize your results in the following table: v/v % MTBE your value % RE 100 lit. value - = ? 4) Convert your v/v % MTBE in gasoline to units of mass % (w/w %) of oxygen in gasoline. Density of MTBE = 0.74 g/mL, Density of gasoline = 0.66 g/mL, Molar Mass of MTBE = 88

Nizkorodov, Sergey

49

Index of /radsafe/files  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348 270Energyradsafe/files [ICO] Name Last modified

50

Index of /research/alcator/facility/Procedures/ASSEMBLY  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modified Size Description

51

Index of /research/alcator/facility/Procedures/DIAGNOSTICS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modified Size

52

Index of /research/alcator/facility/Procedures/IN-VESSEL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modified SizeIN-VESSEL

53

Index of /research/alcator/facility/Procedures/LH  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modified SizeIN-VESSELLH

54

Index of /research/alcator/facility/Procedures/OPS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modified

55

Index of /research/alcator/facility/Procedures/POWER  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modifiedPOWER [ICO] Name

56

Index of /research/alcator/facility/Procedures/RF  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modifiedPOWER [ICO] NameRF

57

Index of /safety/hazardousradioactivematerials  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modifiedPOWER [ICO]

58

Index of /userresources  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modifiedPOWER

59

Index of /xafs13  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348ASSEMBLY [ICO] Name Last modifiedPOWERxafs13 Icon

60

Greatly improved cache update times for conditions data with Frontier/Squid  

SciTech Connect (OSTI)

The CMS detector project loads copies of conditions data to over 100,000 computer cores worldwide by using a software subsystem called Frontier. This subsystem translates database queries into HTTP, looks up the results in a central database at CERN, and caches the results in an industry-standard HTTP proxy/caching server called Squid. One of the most challenging aspects of any cache system is coherency, that is, ensuring that changes made to the underlying data get propagated out to all clients in a timely manner. Recently, the Frontier system was enhanced to drastically reduce the time for changes to be propagated everywhere without heavily loading servers. The propagation time is now as low as 15 minutes for some kinds of data and no more than 60 minutes for the rest of the data. This was accomplished by taking advantage of an HTTP and Squid feature called If-Modified-Since. In order to use this feature, the Frontier server sends a Last-Modified timestamp, but since modification times are not normally tracked by Oracle databases, a PL/SQL program was developed to track the modification times of database tables. We discuss the details of this caching scheme and the obstacles overcome including database and Squid bugs.

Dykstra, Dave; Lueking, Lee; /Fermilab

2009-05-01T23:59:59.000Z