- Init Process init_afd

        AFD works without any user interface and runs as a daemon
        process in the background. The parent of all AFD process
        is the process init_afd. This process ensures that all
        other process are started in the correct order and that
        the infrastructure is setup correctly for AFD to run. Once
        AFD is up running it monitors all process it started. If
        a process fails for whatever reason it notes this in a
        log file and will try to restart this process again.

        IMPORTANT: Do not try to start directly on the command line.
                   There is a commandline tool 'afd' that does this
                   for you. Also do not try to stop AFD by killing
                   init_afd, especially not with the option -9!


   - Description of all Process

        init_afd starts all process in the following order:

           system_log       - log process responsible for writing all
                              system information to the file
                              $AFD_WORK_DIR/log/SYSTEM_LOG.0. The log
                              data is read via a FIFO
                              ($AFD_WORK_DIR/fifodir/system_log.fifo).
           event_log        - Process collecting all events.
           receive_log      - Process collecting information what happens
                              on input.
           transfer_log     - Process collecting information what happens
                              on output.
           trans_db_log     - Process collecting debug and trace
                              information of the different protocols
                              supported by AFD.
           archive_watch    - Process that ensures that files that have
                              been put in the archive are deleted when
                              their time is up.
           input_log        - Process logging each file name that enters
                              AFD.
           output_log       - Process logging each file name that leaves
                              AFD.
           delete_log       - Process logging each file name that is
                              deleted by AFD.
           production_log   - Process logging any processing operation
                              on each file going through AFD.
           distribution_log - Process logging distribution information
                              of a file going through AFD.
           amg              - Automatic Message Generator (AMG), this
                              process evaluates the configuration files
                              $AFD_WORK_DIR/etc/DIR_CONFIG and
                              $AFD_WORK_DIR/etc/HOST_CONFIG. After
                              successful evaluation it will start process
                              dir_check and will monitor its status.
           dir_check        - Process that monitors all local directories
                              for any arriving files.
           fd               - File Distributor (FD), responsible for
                              the transmission of files. To send files
                              it starts process starting with sf_xxx
                              where xxx is the protocol name. For
                              fetching it starts gf_xxx.
           afdd             - To monitor the AFD this daemon is started.
           aldad            - Log process that generates logs in a
                              user specified format.


   - Internal Directory Structure

        When AFD is started it automatically creates the following
        directory structure in $AFD_WORK_DIR:

              $AFD_WORK_DIR/
                    |
                    +-----> archive/
                    |          |
                    |          +--> alias host name 1
                    |                      .
                    |               alias host name n
                    |
                    +-----> etc/
                    |        |
                    |        +-> action/
                    |              |
                    |              +--> source/
                    |              |      |
                    |              |      +--> warn
                    |              |      +--> error
                    |              |
                    |              +--> target/
                    |                     |
                    |                     +--> warn
                    |                     +--> error
                    |                     +--> success
                    +-----> fifodir
                    +-----> files/
                    |         |
                    |         +-> crc
                    |         +-> error
                    |         +-> incoming/
                    |         |      |
                    |         |      +---> user@host/directory 1
                    |         |                   .
                    |         |            user@host/directory n
                    |         |
                    |         +-> outgoing/
                    |         |      |
                    |         |      +---> job ID 1  (1a3d01fa)
                    |         |                .
                    |         |            job ID n
                    |         |
                    |         +-> pool/
                    |         |    |
                    |         |    +-> unique name 1  (505712ae_80f1_0_f017c351)
                    |         |               .
                    |         |        unique name n
                    |         |
                    |         +-> store
                    |         +-> time/
                    |              |
                    |              +-> job ID 1 (1e2b6029)
                    |                      .
                    |                  job ID n
                    +-----> log
                    +-----> messages


   - What happens when a file goes through AFD

        see amg_fd_en.pdf

   - Overview of command line tools

           afd        - start/stop/initialize AFD

           udc        - reread configuration file DIR_CONFIG

           uhc        - reread configuration file HOST_CONFIG

           afdcmd     - tool to send commands to the AFD

           afdcfg     - tool to configure AFD

           afd_status - show status of all AFD process and some additional
                        information such as the number of jobs queued,
                        number of transfer jobs active, different log
                        status, etc.

           fsa_view   - view status of the transmitting part of AFD

           fra_view   - view status of the input directories

           aftp       - send/retrieve files via FTP

           asmtp      - send files via SMTP (mail)


   - Monitoring several AFD's (afd_mon)

       In an environment where you have several AFD's it is advisable
       to use afd_mon. This is a program that collects all status
       information of all AFD's so that they can be made visible via
       the dialog mon_ctrl. If wanted it is also able to collect all
       the log files of the remote AFD's. afd_mon gets the information
       via TCP-socket from the process afdd mentioned above. To setup
       afd_mon you must create a configuration file
       $AFD_WORK_DIR/etc/AFD_MON_CONFIG which looks as follows:

       # +--------------------------------------------------> Alias
       # |            +-------------------------------------> Hostname
       # |            |       +-----------------------------> Port
       # |            |       |  +--------------------------> Interval
       # |            |       |  |  +-----------------------> Connect time
       # |            |       |  |  |  +--------------------> Disconnect time
       # |            |       |  |  |  |    +---------------> Options
       # |            |       |  |  |  |    |   +-----------> Remote cmd
       # |            |       |  |  |  |    |   |    +------> Convert user name
       # |            |       |  |  |  |    |   |    |
       Central-AFD ducktown 4444 5 30 600 1024 ssh donald->daisy