Appendix A - Configuring Your IRIS Explorer Environment

Each machine that you use to execute modules remotely must have most of IRIS Explorer installed on it. In general, the version installed remotely must match the version installed on the local machine.

For example, suppose your local machine, called billiejoe, is networked to another machine named bob. If you can remotely login into bob, and IRIS Explorer is installed on it, then you can very simply set up the two machines for remote execution.

Do this for every host you want to run modules on. When you execute IRIS Explorer again, these host names will be listed on the Hosts menu in the Module Librarian window.

If IRIS Explorer is not installed in the directory /usr/explorer, then you must either:

The easiest thing to do is to install IRIS Explorer in the same location on all machines, which by default is /usr/explorer.

The character (`) surrounding hostname in the previous example is an accent grave, not an apostrophe.

The first word designates the command, and subsequent fields designate arguments or modifiers to the command. Either single or double quotation marks may be used to surround arguments that contain embedded blank characters.

Most arguments to commands may encode UNIX environment variables using the shell dollar-sign notation. For example, $EXPLORERHOME will expand to the value of the environment variable EXPLORERHOME, as will ${EXPLORERHOME}. The C-shell tilde (~) notation for designating home directories is recognized as well. However, strings surrounded by single quotation marks (apostrophes) are not expanded in this manner.

This command defines a list of directories to be used. By default, the existing module path is extended by the list for directories (this is equivalent to using the -append modifier). The default path value is $EXPLORERHOME/modules. Used alone, the command clears the module path to the default path value. If the -prepend modifier is used, the path is added at the head of the current directory list.

The set tempdir command states where to place any temporary files that may be needed during the course of execution, such as named pipes and shared memory arena files, if applicable. Typically, such files are placed in a uniquely named subdirectory of the directory. The default value for the base directory is /usr/tmp.

Because shared memory arenas can become large, it is often advantageous to place the tempdir somewhere other than below /usr.

set arenasize

For a shared memory system, make the maximum size of the shared memory arena the designated size.

The string should be a number optionally followed by mb or kb for megabytes and kilobytes, respectively. This option may also be set from the command line. The default size is 16Mb.

The -append modifier appends a list of modules to a specified category. The list of modules can contain module names, such as GenLat, or directory names. In the latter case, the directory is added to the module path, and all modules and maps in the directory are added to the category. For example,

category myModules ~/explorer/modules
    

adds all modules in directory ~/explorer/modules to the category myModules. You can use the -filter modifier with an arg to filter the list of modules against the argument pattern. The arg accepts shell wildcards such as *, ? and [. For example,

category Readers -filter Read* Modules
    

puts all the Read* modules in directory Modules in a category called Readers.

The modifier -command may be used to define an alternate way of starting a local communications server (LC) on remote hosts. The single argument after -command (which must be enclosed in quotation marks if it contains blanks) specifies the alternate command.

The UNIX command IRIS Explorer uses to start the LC on a remote host is the given command (rsh by default) followed by the hostname, followed by a shell command that will be invoked remotely to start the LC. For example, suppose this appears in your .explorerrc file:

host bob -command "myrsh -x"
    

IRIS Explorer will invoke

myrsh -x bob <shell command to start the LC>
    

If the word HOST appears in the alternate command, the hostname is substituted in its place when executing the command. Therefore, you can use the command:

host bob -command "rsh HOST -l joe"
    

to start a remote LC under the account joe on bob.

If it responds with the name of your remote home directory, all is well. If it responds with Permission denied you need to enable rsh.

You can enable access to that machine by creating a file named .rhost in your remote home directory. See the rsh(1) manual page for details.

The -command modifier on the host line allows the redefinition of the command to use to try to get a module communications server running on a remote machine. By default, the rsh command is used. This may not be appropriate for all installations, because rsh does not allow for password prompting and the associated protections.

The command cxrexec has the same command line options as rsh. Either command can be modified in .explorerrc to add options. However, when additional rsh or cxrexec options are listed, the entire command must be enclosed in quotation marks:

host superhost -command "rsh HOST -l guest"
host superhost -command "cxrexec HOST -l guest"
  

These examples demonstrate another feature of the alternate command option: wherever the word HOST appears, the name of the remote host will replace it.

If the word HOST does not appear in the command, it is appended to the end. Hence, the following two lines are functionally equivalent:

host superhost -command "rsh HOST"
host superhost -command "rsh"
  

Other UNIX programs may be used instead of rsh and rexec, depending on local conventions.