Enabling and Disabling SNAplus2 on the Local System

You must enable the SNAplus2 software before you can use any SNAplus2 tools (including the Motif administration program). Normally, the software is enabled automatically after you install SNAplus2, but if necessary you can enable it manually.

For UNIX

This section explains how to enable and disable the SNAplus2 software on a HP-UX server or client.

For Windows

For information about enabling SNAplus2 on a Windows client, see Chapter 11 “Managing SNAplus2 Clients”

End of Section

Specifying the Path to SNAplus2 Programs

SNAplus2 executable programs are stored in a directory specific to SNAplus2; when you run the programs, you need to specify the path to this directory. You can specify the path either by adding the directory to your PATH environment variable before you run the programs for the first time, or by including the directory name each time you run the programs.

The Motif administration program is stored in the directory /opt/sna/bin/X11, and the other programs are stored in the directory /opt/sna/bin. If you add these directories to the definition of the PATH environment variable in your .login or .profile file, SNAplus2 locates the programs automatically. Alternatively, you can specify the directory name when you run the program, as in the following examples:

/opt/sna/bin/snap start

/opt/sna/bin/snapadmin query_node_all

/opt/sna/bin/X11/xsnapadmin

The sample command lines shown in this manual assume that you have added the directories to your PATH environment variable, and do not include the directory names.

Enabling SNAplus2 Servers

This section describes how to enable SNAplus2 on a computer that was installed as a server (that is, with the SNA node components installed). If you are enabling SNAplus2 on a client, see “Enabling SNAplus2 on HP-UX Clients”.

You must enable SNAplus2 on the local system before you can configure or manage the local node (either locally or from a remote SNAplus2 node).

To enable the SNAplus2 software, enter the following command at the HP-UX command prompt:

snap start [ -s ] [ -m kernel_memory_limit] [ -t ]

You can also enable SNAplus2 automatically at system startup by inserting the snap start command into the startup file on your system. (When you install SNAplus2, the installation utility automatically updates the startup file with this information.)

The parameters and options for the snap start command are as follows:

-s

Specifies that SNAplus2 should not write messages to the system console. If you do not use this option, SNAplus2 writes messages to the console when it ends, and also writes the text of certain error log messages to the console as well as to the log file.

-m kernel_memory_limit

Specifies the maximum amount of kernel memory, in kilobytes, that SNAplus2 should use at any time. (Kernel memory is used for internal data structures.) If a component of SNAplus2 attempts to allocate kernel memory that would cause the total amount of memory currently allocated to SNAplus2 components to exceed this limit, the allocation attempt fails.

If you do not use this option, kernel memory usage is not limited.

-t

Activates tracing on all interfaces between kernel components, and also client/server and back-level client/server tracing. (This option does not turn on DLC tracing.) Tracing enables you to diagnose problems that occur during startup. If you do not use this option, tracing is inactive at all interfaces; you can then activate it on specific interfaces as required, using the command-line administration program snapadmin.

Tracing on all interfaces degrades the performance of SNAplus2 components. After the software is enabled, you can use the command-line administration program snapadmin to stop tracing on any interfaces where it is not required. For more information about tracing, refer to the HP-UX SNAplus2 Diagnostics Guide.

SNAplus2 writes messages to standard error (normally your terminal's screen) to indicate that it is initializing, and to indicate whether initialization completes successfully.

If initialization fails, the messages include information about the cause of the error, and (where appropriate) additional information such as the HP-UX operating system error message. The text written to standard error may also include a message indicating that you can find further information in the error log file. The snap start command then ends with a nonzero exit code that indicates the nature of the error.

For more information about exit code values, refer to the HP-UX SNAplus2 Diagnostics Guide.

Disabling SNAplus2 Servers

Disabling the SNAplus2 software on a server automatically stops the SNAplus2 node and its associated connectivity components. Disabling SNAplus2 also stops any other processes (such as a 3270 emulation program) from using SNAplus2 resources on this server.

In general, you should stop individual services as users finish using them, and only disable the system when there is no SNAplus2 activity. Disabling the SNAplus2 software on a client stops any programs running on the client from accessing SNAplus2 facilities.

If you need to disable SNAplus2 while users are active, warn users that SNAplus2 is stopping, and give them time to finish their activities before you disable the software. Use the Motif administration program or the command-line administration program to view details of active users.

If a 3270 emulation program is using LUs on the node when you disable the SNAplus2 software, all 3270 emulation sessions using these LUs end. The program continues to run, but the user cannot use the sessions until the software is re-enabled. If the RJE workstation program is running, it automatically exits. Applications using the APPC, CSV, LUA, NOF, or MS APIs are notified by a COMM_SUBSYSTEM_ABENDED return code, HLLAPI applications by a HARC_SYSTEM_ERROR return code, and CPI-C applications by a CM_PRODUCT_SPECIFIC_ERROR return code.

To disable the SNAplus2 software, enter the following command at the HP-UX command prompt:

snap stop

If SNAplus2 is disabled successfully, snap stop returns an exit code of 0. Any other exit code indicates that an error occurred and that the SNAplus2 software was not disabled. Refer to the HP-UX SNAplus2 Diagnostics Guide for more information about exit code values.