[Gb-ccb] Updated documentation

[Martin Shepherd]

I have now finished the CCB documentation, which can be found
either via the web, at:

  http://www.astro.caltech.edu/~mcs/GBT/index.html

or on the Green Bank computers, in the following directory.

  ~mshepher/doc/

The new documents are:

  ccb_monitor_status.pdf  -  Documentation of the ccb_monitor_status program.
  ccbserver.pdf           -  Documentation of the CCB server program.
  ccb_computer_setup.pdf  -  Documentation of the installation and future
                             maintenance of Linux and the CCB software on
                             the embedded CCB computers.

Beware that the above documentation includes a couple of features that
either don't exist yet, or that are pending installation. In particular:

  1. In the diagnostics section of the ccb_computer_setup document, it is
     stated that when the CCB server program is run as a dameon, it sends
     copies of all log messages to syslog (ie. /var/log/messages). Although
     indeed, the updated CCB server program does do this, it hasn't been
     installed yet.

  2. Since the backup and restoration procedures are still pending
     getting the RAM booting working, the documentation of the backup
     and restoration procedures, document what I intend that these
     procedures will look like, when they are completed.

I have also made the following minor changes to the code, none of which should
affect the manager.

1. As mentioned above, the CCB server program now sends copies of log
    messages to syslog, when it is being run as a daemon. Previously, they
    were only sent to the currently connected manager, if any, which meant
    that if the manager couldn't connect, then there was no way of seeing
    any error messages from the server, that might explain why. This is
    pending installation.

2. I have embedded the workaround for the problem that Brian encountered,
    into the CCB server program. The server now won't respond to a new
    connection requested from a manager or diagnostic program, until 3
    seconds have passed since the previous connection was terminated.

4. It appears that the Tcl/Tk libraries were recently upgraded on the
    GB computers, and that in the upgraded version, some extra "const"
    attributes have been added to some callback function arguments,
    Thus I've had to modify my Tcl callback functions, all functions
    that their const arguments were passed to, and all pointers to
    elements of these arguments. Since I needed the CCB code to
    continue being compilable against the previous version of Tcl/Tk,
    which is what we have installed at Caltech, I have done this using
    a conditionally assigned macro. Anyway, the long and the short of
    this is that the libtclclient library now again compiles without
    warnings, both at Caltech and at GB.

Martin