ARC2TRIGII: Details
arc2trigII selects additional snippets of interest to save, by doing the following:

    I. Get the coordinates of mandatory stations. Either from the station list, or by a search of the DBMS.
    II. For each event:
      1) Select the relevant stations:
        a) All stations within the distance implied by the
           magnitude-distance table. This can be from a hypoinverse station
           list or the DBMS. If from a station list, this will have been read
           once at startup. If from the DBMS, the DBMS will be queried for
           stations within the appropriate rectangle for this event.
        b) All mandatory stations.

      2) For each selected station, compute the snippet to be saved:
        a) Within a specified epicentral distance, ignore the travel time table,
           and save all data from origin time through S arrival time.
        b) Outside this distance, use the travel-time table as in usnsn_loc2trig,
           and use that to compute snippet times.
        c) All snippets will be padded with a specified safety margin of pre
           and post computed snippets times.
    ----------------------------------------------

Determining Amount of Data To Save(Snippet Length)
The program saves an interval of waveform data, called a snippet, from each of a list of channels. For picked stations(from the arc message), the program is setup to save a snippet of waveform data, starting X seconds before the Pick time, and lasting until Y seconds after the Pick time. X is configurable via the config file, and Y is dependent upon the magnitude of the event(either overall, or based on a coda measurement for that channel.) For unpicked stations, snippet length is computed as is described above in the outline.
Authors
Story: The grand idea (behind authors) is that messages which relate to an event shall include an author field. In particular, the trigger message shall include, after the "EVENT ID:", an "AUTHOR:", which is followed by the author id. The author id is to be a series of logos, separated by :'s. Each logo is represented as three sets of three ascii digits. The first logo is the logo of the module which originated this event, followed by the logos of the modules which processed it.
So hypoinverse (eqproc) created the event by emitting an arc message. It should have stuck its logo in the author field. It doesn't, because we don't have the stomach to change eqproc. So we make up for it here: we know the logo of the message as it came to us, and we know our own module id, so we write eqproc's logo and our own into the trigger message which we produce.
Logfile Name
The log file name is built from the name of the configuration file.
Ring Flush Upon Startup
The incoming transport ring is flushed at start time to prevent confusion if the module is restarted. This has the effect of removing all messages that were already on the ring when the program was started, this has the net effect of preventing the program from acquiring any data that was generated prior to the program's starttime.