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mlogger - MIDAS Logger

The MIDAS Logger, mlogger is supplied in the MIDAS package. This utility can perform several functions (selected by the user via the /Logger ODB tree ) including:

  • logging System messages to a Message file or as message events
  • logging information to a mySQL database
  • writing information to an electronic logbook
  • collecting and logging history events
  • logging experimental data from one or more frontends to storage device(s) such as disk or tape
  • multiple Logging Channels can be defined
  • several different storage devices, formats and compression levels can be selected
  • data can be logged to different subdirectories on disk
  • data can be logged to a remote computer, using the FTP mode
  • events can be selected for logging by Event ID or Trigger mask
  • Event Filtering can be implemented
  • runs can be automatically stopped and restarted after a certain number of events, or a certain time
  • the complete ODB contents can be saved
    • into a file at the beginning and/or end of run
    • and/or into the data stream

The mlogger utility runs on the backend computer, receiving events from the buffer manager. It supports three type of storage devices so far, i.e.

  • Disk,
  • Tape
  • FTP channel to a remote computer.

Data can currently be written in five different formats :

  • MIDAS binary,
  • ASCII,
  • ROOT
  • DUMP

The user may of course write their own custom data logger to save the data in any format they choose.

Starting mlogger utility

       [-h ] : help
       [-e exptname ] : experiment name (see odbedit - ODB Editor and run control utility)
       [-D ] : start program as a daemon (UNIX only).
       [-s] : Save mode (debugging: protect ODB).
       [-v] : Verbose (not to be used in conjunction with -D).
    >mlogger -D 


  • When mlogger is started for the first time, it creates the /Logger, the /History and the /Elog ODB trees with default values.
  • The mlogger application requires an existing /Equipment ODB tree.
  • Once mlogger is running, you should be able to monitor its state with mstat or with mhttpd.