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Stager |
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Stager runs from a graphical user interface and is responsible for managing experimental data storage. Stager has the following features:
- Automatically stages disk based event data to tape in Tar format according to user settable strategies.
- Non-volatile state allows restart and go from saved settings.
- Works within the NSCL standard experiment directory structure.
- Runs the user's Readout program through the ReadoutShell Gui providing a GUI for controlling experiment runs.
- Can save data to remote tape drives.
- Breaks stage operations across tapes as needed.
- Puts several files on a single tape
- Creates a log of the runs logged to tape so that the user can locate a run within a specific tar file on a specific tape.
- Allows users to place runs in a "Retained Run" list to save them across stage passes.
The remainder of this documentation describes:
- How to run stager
- What actions stager takes when it starts up.
- What stager does when it runs.
- The stager GUI
How to Run Stager
Stager consists of a set of TCL/Tk scripts and packages in the /usr/opt/daq/Scripts directory. It is therefore necessary to be sure that the TCLLIBPATH environment variable includes /usr/opt/daq/Scripts, and that the LD_LIBRARY_PATH environment variable includes the /usr/opt/daq/Lib directory. Once these requirements have been met run stager by typing:
/usr/opt/daq/Bin/Stager
at the shell prompt.
Startup Actions
On startup, Stager attempts to source the file ~/experiment/.stagerconfig. If this file does not exist, the stager prompts you for its configuration through it's GUI. If this file does exist, Stager asks you to confirm the settings in the configuration file with the following dialog window:
If all of the settings are correct, click Accept otherwise clicking Reject causes Stager's GUI to prompt for a new configuration.
· For information about each parameter, Click on it in the figure above.
Once the Stager has been configured, it begins Normal Operations, and displays it's GUI.
What Stager Does
Stager starts up the Readout program specified by its configuration. The Readout program is started through the ReadoutShell GUI front end.. This allows the user to interact with the experiment readout subsystem through a graphical user interface front end.
Every 5 seconds, stager performs the following actions:
· Update its configuration file
· Performs a Stage Evaluation Pass.