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Writing data to tape with the Lazy Logger

This document explains how to make sure that data is being written to tape, as well as disc, by MIDAS.
  1. The tape logger runs during data acquisition and archives MIDAS (.mid) data files to DLT tape. It can be started correctly by the start_daq script (see Starting the MIDAS data-acquistion system on isdaq04). When running, it will appear at the bottom of the MIDAS status page as "Lazy_Tape", shown below:

    Web status page

  2. The transfer progress is also shown on the status page, and a log of the archived files is maintained in the data directory in file lazy_log_update.log.
  3. The logger is controlled from the ODB. The standard settings may be seen in Lazy Settings. The Stay Behind setting subtracted from the current run number is the last run to be backed up. The Data directory is the path to the current .mid files. If Maintain free space % is non-zero the oldest data files in the path are erased in order to keep a set percentage of free space on the disk. The tape name can be set by changing the List label field.
  4. If needed, a backup tape should be mounted in the DLT. Be sure that the orange mark, denoting that the tape is write protected, cannot be seen. Entering the tape name into the list label starts the tape transfer (use "DRXX" where XX is the current tape number - sticky labels can be found in one of the cabinet drawers near the tape drive). Data is always appended to any already on the tape.
  5. If the tape is full, a MIDAS alarm will be triggered. Set the label to (empty) and reset the alarm. When the green light on the drive comes on the tape can be removed from the drive.
  6. Contact PA, KO or JEP if there is a problem.
Art Olin
March, 2003
JEP
22 December, 2005