Configure the data archiver.

Mandatory Arguments:

(none)

Optional Arguments:

Count interval

The archiver sub-sampling interval. Only one frame of the specified number of consecutively received frames, per system, are archived. The rest are discarded. To archive all data, set this to 1.

Count combine

For the CBI, this parameter was used to tell the archiver how many consecutive frames should be combined to form each archived frame. However for QUIET, the optional combination of frames was replaced by optional sub-sampling. The combine parameter has now become a backwards-compatibility alias for the new interval parameter described above.

Wdir dir

The directory in which to place subsequently opened archive files.

Count file_size

The number of frames to record per archive file before starting a new file. The default is 0, which tells the archiver to keep writing to the current file indefinitely.

Example 1:

The following example tells the archiver to only archive every 20th frame, discarding the rest. It also tells the archiver that the next time that a new archive file is created, it should be placed in the /scr/cbi/data directory.

  archive interval=20, dir=/scr/cbi/data

Example 2:

The following example tells the archiver to start a new archive every time that the current file contains 1000 frames. This keeps the size of each file reasonably small, thus enabling faster access to a given start time when the archive is read.

  archive file_size=1000

Context:

The archiver part of the control program receives 1-second frames of the register values from the mount control system and from receiver control systems. Frames from these different systems that have equivalent timestamps, are combined into frame groups. Frames whose timestamps can't be matched up with those of other groups, are placed in their own frame groups, along with empty frames for other systems. The archive command controls which, if any, of these frame groups are written to archive files, where archive files are to be recorded, and how often to start new archive files.

The optional interval argument.

To save disk space when observations are not being performed, the interval argument allows one to tell the archiver to only archive a subset of the frames. If it is set to 1, then all frames are archived. However if it is set to n, where n>1, then from each consecutive n frame-groups, only one is archived, and the rest are discarded.

The optional dir argument.

While the directory in which archive files are to be placed can be specified by this command, to explicitly open an archive file you should use the open command.

The optional file_size argument.

By default, once an archive file has been opened, the archiver indefinitely records all archive frames in a single file. This has the potential to create a huge file, which then forces the offline analysis software to read a lot of unwanted data to reach samples near the end of the file. To avoid this, the archiver provides the option of breaking up the archive output stream into multiple files of a given maximum size. The size is specified as an integral number of frames. Whenever that number of frames has been written to a given file, that file is closed and a new file is opened. All such files have their start times encoded in their file names, so the offline software can then use this to locate the files that contain a given time range.