CPU(4)                                                     CPU(4)

     NAME
          cpu - cpu server resource

     SYNOPSIS
          grid/srv/cpu
          grid/runcpu

     DESCRIPTION
          Cpu is a file server that provides a processing resource.
          This resource imports a namespace from one or more external
          sources and executes selected commands within it. Cpu cre-
          ates its own namespace containing three files ctl, cmd and
          ns which are used to configure the processing task prior to
          execution, this namespace is exported and served on stdin.
          In order to configure a processing task, a client must first
          mount the cpu namespace. Once this is done, reading the cmd
          and ns files will display the current configuration of com-
          mands to be executed or directories to be imported respec-
          tively. The ctl file is used to modify the current configu-
          ration and accepts the following input:

               add cmd command

               add ns path address

               del [cmd|ns] index

          Where command is the name (including full path and parame-
          ters) of a command to be executed.  Path is the name of a
          directory to import from the exported namespace available at
          address and index is the index (as shown when reading the
          cmd and ns files) of the command or directory to be removed
          from the configuration.

          For example, to import /dis and /dev from a resource export-
          ing a Styx (see intro(5)) namespace at address
          tcp!200.1.5.53!7003 and then run ls -l and du, the following
          commands would be used:

               echo 'add cmd /dis/ls -l' > ctl
               echo 'add cmd /dis/du' > ctl
               echo 'add ns /dis tcp!200.1.5.53!7003' > ctl
               echo 'add ns /dev tcp!200.1.5.53!7003' > ctl

          Reading the cmd and ns files will give the following output:

               cmd
               1: /dis/ls -l
               2: /dis/du

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     CPU(4)                                                     CPU(4)

               ns
               1: /dis (200.1.5.53!7003)
               2: /dis (200.1.5.53!7003)

          Once the client disconnects from (unmounts) the cpu, the
          selected namespaces will be imported and the commands exe-
          cuted. Note: A cpu does not have any namespace of its own.
          All required namespaces must be imported, for a simple com-
          mand such as ls, the minimum recommended namespace to import
          would be: /chan /dev /dis /module

          Register(1) may be used in conjunction with cpu to register
          it with a registry(4) and to export and serve its namespace
          across dial(2) network connections. Incoming connections may
          also be displayed visually using monitor(1). For example:

          grid/register [ options ... ] { grid/srv/cpu } |
          grid/srv/monitor 2 'CPU resource'

          This set of commands is encapsulated within the shell script
          runcpu which will automatically register cpu with a
          registry(4) if possible and start up the graphical display
          to show connections to the resource. There is no need for
          the user to execute cpu outside of runcpu unless the names-
          pace it provides is required to be accessible in a different
          way to that provided by register(1).

     SOURCE
          /appl/grid/srv/cpu.b

     BUGS
          At the moment, Cpu will only import namespaces across an
          unauthenticated connection as provided by ns(1).

     SEE ALSO
          monitor(1), ns(1), register(1), session(1)

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