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The front end code uses socket-driven inter-process communications this year, in order to accomodate the new HP Filter machine, and to facilitate hardware migration in online ROPE. There are two main server-client models used on the front-end:

  1. FilterServer-FilterClient - This year the Filter is an HP 742/747 super workstation. The IP name of this node (on public ethernet) is hpop7f2. You can telnet into this node by specifying this IP name, and by logging in as user filter. Do not maintain unused connections on this machine, and do not run anything that is not strictly needed.

  2. RopeServer-RopeClient - Dense data files from either online or offline processes are distributed from the RopeServer to any RopeClient process that requests a file. As described in the next section, the RopeClient always seeks an online file first. This assures that the online processing will get first priority.

    The RopeServer maintains a state table of the ROPE engines that it knows about. This information can be used to understand the general state of ROPE processing, and the health of a ROPE engine. RopeClients communicate three kinds of information to the server - a request for a data file, a change of state or a notification that it has finished a file. The states that the server understands are:

    Note that in test states the ROPE engine only wants test files.

    The server also has knowledge about the past 10 files that a ROPE engine has dealt with.

Note about online verses offline running.