Calibration Files: Access Overview

Most Gleam runs require access to calibrations which are stored in individual files in either XML or ROOT format. Although they may reside anywhere, the master copies of production calibrations are, by policy, kept in the SLAC central file system. In practice, most other calibrations are kept there as well. If the central file system is not accessible to the machine on which Gleam is running, the calibration files can be copied to a local file system which is.

Gleam finds the files it needs by looking them up in a database whose entries include a field which is the path to the file. For production files, the path normally begins with a reference to the environment variable LATCalibRoot. A typical path appears in the database as:

$(LATCalibRoot)/CAL/LAT/tholdci_16.xml

For Gleam to be able to find calibration files:

• The master calibration files - or a copy - must be accessible.

• The LATCalibRoot environment variable must be defined so that it points to the root directory of the files.

SLAC Central Linux

If you are running on a noric, or on a similar centrally-maintained, machine with access to shared SLAC unix file systems, you may not have to do anything. The files are readily accessible, and if you normally run the Glast Offline set-up file group.cshrc, the environment variable LATCalibRoot will have been set for you.

If not, you'll need to set it yourself. At the time of this writing (July 18, 2006), the correct value is:

/afs/slac/g/glast/ground/releases/calibrations/

UW Terminal Server

A copy of some calibrations is maintained on this system. To access it from Gleam, refer to: Set Environment Variables.... and set the environment variable LATCalibRoot to:

f:\glast\calibrations

Windows node on SLAC Network

The central SLAC unix file system is normally visible to Windows computers on-site. To access it from Gleam, set the environment variable LATCalibRoot to:

\\Slaccfs\slac_afs\g\glast\ground\releases\calibrations

Remote Linux site (user)

Check with a local expert to find out if there is a copy of the calibrations at your site. If there is, you only need to set LATCalibRoot to the root directory of this copy. Typically this is done at the same time other site-dependent variables like GLAST_EXT are defined.

Remote Linux site or desktop (maintainer)

rsync may be used to copy calibrations to a local disk and keep the local version current. The simplest strategy is to copy everything under/afs/slac/g/glast/ground/releases/calibrations/, but this is substantial (as of May 2006 just under a gigabyte).

Note: Many of the files are not calibrations, and therefore not of interest.

However, if you have space available, and you wish keep the calibrations under the root directory /data/calibrations, you can do so by issuing the following command:

Note: To keep your files up to date, reissue this command periodically, and it will copy only the files not already at the local site.

To access the files, set the environment variable as follows:

• If using csh or tcsh shell:

  $ setenv LATCalibRoot /data/calibrations

or

• For a bash-like shell:

  $ LATCalibRoot=/data/calibrations;export LATCalibRoot

Remote Windows desktop