You can see the characteristics of a link and delete a link by using the Show Links... menu item. This menu item displays the Links dialog box, which is illustrated in Section 11.5.

If you click on the Show Link... button, a dialog box appears with detailed information about the selected link. This dialog box contains the same information as shown in the Complete Link... dialog box, illustrated earlier in Section 11.4, except that the Retain This Source button does not appear. You can edit the Relationship and Description entry boxes.

To delete a link, click on the Delete button in the Links dialog box. As soon as you delete a link, the object becomes an orphan; to make it no longer an orphan, delete the link by selecting the object to which it is linked and then using the Delete button in the Show Links... dialog box in the appropriate hyperapplication.

11.8 Using Other Hyperapplication Features

Whenever you perform a Visit or Go To operation, the LinkWorks history is updated to reflect your operations. To see the history of your navigation operations, choose the Show History... menu item, which displays the following dialog box:

You can use this dialog box to visit objects that are listed and to modify history information.

• To visit an object in the history list, select it and click on Visit.
• To modify history information, select an object to be modified and click on the Show Step... button to display the Step dialog box:

  ---

  
  You can edit any of the Description entries, and you can change the Follow Type and Operation settings. The ability to modify history information becomes important if you want to create or modify a path. (See Section 11.9 for more information on paths.)

The Go Back menu item, described earlier in Section 11.5, removes the last step from the history and performs a Go To operation to the previous step. Thus, Go Back lets you step backward through the history list while deleting steps.

The Step Forward menu item moves to the next step in the currently active path and performs the step. Thus, Step Forward lets you step forward through the current active path.

11.9 Advanced LinkWorks Concepts

Information about links that you make and follow is stored in a hyperinformation linkbase. By default, you have a linkbase named LWK_PERSONAL in your login default (VMS) or home (ULTRIX) directory. However, you can cause LinkWorks to use another linkbase as your default personal linkbase by defining the VMS logical name LWK_PERSONAL or the ULTRIX environment variable LWK_PERSONAL to point to that linkbase file. Although you probably will not need to create additional linkbases, you can create them by using the LinkWorks Manager application.

Each linkbase contains a number of hyperinformation objects. These objects let you organize your links as they become more numerous and complex. The same principle is included in many software applications. For example, in Mail you begin with one folder (MAIL) in one drawer (your primary mail file). As you receive more and more messages, you organize them into folders. If the number of folders grows sufficiently, you might decide to create new drawers, each with several folders.

The hyperinformation linkbase can contain the following objects:

• Linknets
  Any time you make a link, information about that link (such as identification of its source and target) is recorded in a linknet. Initially you have only one linknet called Personal Links, but you can create additional linknets.
  By analogy, Mail allows you to store messages in folders, and LinkWorks allows you to store link information in linknets.
  You can control two operations that LinkWorks performs with linknets: recording and activating.
  • Recording determines the linknet in which links are stored. You can record into only one linknet at a time. If you disable all recording, no link information is stored in the linkbase.
  • Activating controls which links you can follow and, if highlighting is enabled, which links are visible. If highlighting is enabled, links for all active linknets are highlighted. You can activate or deactivate linknets, depending on which links you want to be able to follow.

• Linknet lists
  A linknet list can contain linknets and linknet lists. A common use of a linknet list is to organize related linknets so that you can activate and deactivate all the linknets in the list with a single operation. A linknet or linknet list can be a member of several linknet lists.
  As a partial analogy, Mail drawers contain folders, and you can create additional drawers, as well as folders within those drawers. Linknet lists can contain linknets, and you can create multiple linknet lists, each of which can contain several linknets. However, linknet lists differ from Mail drawers in that a linknet list can contain other linknet lists (drawers cannot contain drawers), and a linknet can be in several linknet lists (a folder cannot be in multiple drawers).
• Paths
  A path is a historical record of links that have been followed. You can create a path, and then you and others can follow the path without having to re-create the links. Paths can make certain tasks convenient and have great potential as teaching tools (for example, a teacher or manager providing a path through information for others to follow).
• Path lists
  A path list is a collection of paths. You might create path lists if the paths you want to keep track of become too numerous or complex.

For information about creating and using linkbases, linknets, linknet lists, paths, and path lists, see the chapter on LinkWorks Manager in the DECwindows Motif for OpenVMS Applications Guide.

DECwindows expands your computing opportunities by letting you run applications across a network. Distributing applications in this way means that they can run on another computer and be displayed on your workstation, so you can take advantage of larger computers that may be better suited to a specific computing task. Although the application runs on another system, it looks the same as any other application running on your workstation. You can even run applications on an ULTRIX system for display on your VMS workstation.

By default, however, your workstation monitor can display only those applications that are running on your workstation. This prevents users on other systems in the network from displaying applications on your workstation monitor or from capturing and displaying your keystrokes (including your password) on another monitor.

You can run an application on a remote system for display on your workstation by completing three easy steps:

1. Authorize yourself on your workstation to display output from applications that run on the remote system.
2. Log in to the remote system and direct the display to your workstation with the DCL command SET DISPLAY command.
3. Enter the DCL command line that runs the application.

These steps are described in more detail in the sections that follow.

12.1 Enabling Network Access to Your Workstation Monitor

Initially, you are authorized to run applications only from your workstation, where your current session is running. This means that you cannot log in to another system and run applications for display on your workstation monitor unless you authorize yourself to do so.

From Session Manager, you can give users access to your workstation display by specifying their nodes and user names. By default, you give access to users on systems that are connected by DECnet--VAX software. DECnet--VAX is one transport by which nodes in a network communicate. (The transport passes information between the application and the display.) You can also give access to users on systems running other transports, such as TCP/IP software.

The user name, node name, and transport information you provide act as filters to screen out all except a selected class of users. For example, you can give access to your workstation to user WINKEN on node BLINKN, which is a node on a system that is running DECnet software. By giving access only to WINKEN on node BLINKN, you deny access to another user WINKEN on node NOD.

12.1.1 Authorizing Workstation Access in a DECnet Network

To authorize yourself or others to display applications on your VMS workstation in a DECnet network:

1. Choose Security... from Session Manager's Options menu.
   Session Manager displays the Security dialog box.

   ---

   
2. In the Node entry box, type the node name of the user you want to authorize.
   The node name cannot be a cluster alias (a name that represents multiple nodes configured in a VAXcluster); it must identify an actual node.
3. In the Username entry box, type the user name of the user you want to authorize.

   Note If you are running an application on an ULTRIX system, you should authorize the user a second time, but this time type the user identification number (UID) of the user you want to authorize. This is necessary because some applications identify the user with the user name and some with the UID. (The UID is a small number---less than 3200.)

   
   The transport information is already supplied. The default transport, DECnet, allows connections from one node to another. An application that is running on your workstation uses a local transport that is included in DECnet authorization.
4. Click on Add.
   The user name (or UID), node name, and transport are added to the list of authorized users.
5. Click on OK or Apply.

The following example shows how to add your name to the list of authorized users of your display, thereby ensuring that you can display DECwindows applications on your workstation from system ZEPHYR.

Be aware that each node, both the source and destination, must be defined in each other's network node database. For example, to display applications on node HUBBUB from ZEPHYR, HUBBUB must be entered in ZEPHYR's network node database, and ZEPHYR must be defined in HUBBUB's network node database.

You can use an asterisk (*) wildcard in the Username or Node entry box to authorize entire classes of users. For example, to authorize all users who are logged in to node HUBBUB to display on your workstation, type an asterisk (*) in the Username entry box and HUBBUB in the Node entry box. Then click on Add. Session Manager adds that text to the list of authorized users. It's a good idea to give access to only those users who you know require it. Giving access to an indeterminate number of users is not recommended because this practice can compromise the security of your system.

12.1.2 Authorizing Workstation Access in an Internet Network

If your system is part of an Internet (TCP/IP) network, you can run applications across that network. An Internet network can connect

• VMS systems with other VMS systems
• ULTRIX systems with VMS systems
• ULTRIX systems with other ULTRIX systems

To run applications on a remote system for local display, you'll need both a transport interface (like the TCP/IP transport interface included in DECwindows) and transport software (like the VMS/ULTRIX Connection ([UCX]) software product) to connect the applications with the workstation display. If you have another vendor's transport software, make sure you have a compatible transport interface. If you're not sure whether you have both software components, see your system manager.

To authorize yourself or others to display applications on your VMS workstation in an Internet network:

1. Choose Security... from Session Manager's Options menu.
   Session Manager displays the Security dialog box, as illustrated in the preceding section.
2. In the Node entry box, type the node name of the user you want to authorize.
   The node name cannot be a cluster alias (a name that represents multiple nodes configured in a VAXcluster); it must identify an actual node. To authorize your own node, you must enter a zero (0).
3. In the Username entry box, type an asterisk (*).
   You cannot authorize individual users in a TCP/IP network. The asterisk indicates that every user on the node you specify can display application output on your workstation.
4. Delete the text in the Transport entry box and type TCPIP.
   If you're using another vendor's transport, type the name of that transport in this entry box.
5. Click on Add.
   The asterisk, node name, and transport name are added to the list of authorized users. The node name will be displayed in uppercase letters, but will match any lowercase letters in the node name.
6. Click on OK or Apply.

As in a DECnet environment, each node, both the source and destination, must be defined in each other's network node database. For example, to display applications on node HUBBUB from ZEPHYR, HUBBUB must be entered in ZEPHYR's network node database, and ZEPHYR must be defined in HUBBUB's network node database.

The following example shows how to make sure that users on system ZEPHYR can display DECwindows applications on your workstation.

12.1.3 Disabling Workstation Access

1. In the Authorized Users list box, select the transport, node, and user name you want to remove.
2. Click on Remove.
   The entry is removed from the list of authorized users.
3. Click on OK or Apply.

Once you are authorized to display applications on your workstation from another system, you can log in to other systems and direct the display to your workstation by using the DCL command SET DISPLAY. Although DECwindows must be available on these systems, they need not be workstations.

The SET DISPLAY/CREATE command affects only those applications running in the window from which you issue the command. This means that, although you might be running one application on your workstation and displaying it on another workstation, you can continue to run applications on your workstation for display in other windows on your monitor.

From DECterm or a FileView DCL Command window, log in to the remote system using the DCL command SET HOST, and enter the following command:

$ SET DISPLAY/CREATE/NODE=display_node

In this command, display_node is the workstation on which you want to display the application. You specify the /CREATE qualifier the first time you want to run an application and direct the display. If you subsequently direct the display to another system, omit this qualifier. For information about additional SET DISPLAY command qualifiers you can use with the /CREATE qualifier, see the OpenVMS DCL Dictionary.

Enter the DCL command SHOW DISPLAY to make sure the display now points to your workstation. For example, if you logged in to remote system ZEPHYR from your system HUBBUB and directed your display back to HUBBUB, you see this information:

Device: WSA2: Node: HUBBUB Transport: DECNET Server: 0 Screen: 0

Device is your workstation device and might vary each time you use SET DISPLAY and SHOW DISPLAY. Node is the network system to which the display is now pointing. Transport refers to the transport (DECNET, LOCAL, or TCP/IP) that passes information between the application and the display. Server and Screen are usually 0. (For information about using the /SERVER and /SCREEN qualifiers, see the OpenVMS DCL Dictionary.)

You can now run your application on ZEPHYR for display on HUBBUB if you are authorized to do so. See Section 12.3 for more information.

When you finish running the application, you can either disable the remote display or direct the display to a third system, as described in the next two sections.

12.2.2 Disabling a Remote Display

Specifying the /DELETE qualifier with the SET DISPLAY command disables further connections to the remote display. For example, to disable the remote display from ZEPHYR to HUBBUB, enter the following command:

$ SET DISPLAY/DELETE

Any applications you run on ZEPHYR are no longer displayed on HUBBUB.

12.2.3 Directing a Remote Display to a Third System

You can direct the display to a third system by entering the SET DISPLAY command and the name of the node to which you want to direct the display. For example, to direct a remote display to a third system named ROMA, enter the following command:

$ SET DISPLAY/CREATE/NODE=ROMA

Enter the command SHOW DISPLAY to see that the display now points to ROMA.

To direct the display to an ULTRIX workstation if the node name contains lowercase characters, you must surround the display node name with quotation marks. For example, to display on ULTRIX node pluto, enter the following command:

$ SET DISPLAY/CREATE/TRANSPORT=TCPIP/NODE="pluto"

Quotation marks are optional for a node name that contains all uppercase characters.

12.2.4 Directing a Remote Display to Your Own System

If you access your own system using the SET HOST command, you need to direct your display before you can run applications on your system. If your system is HUBBUB, you can define your display using either of the following commands:

$ SET DISPLAY/CREATE/TRANSPORT=LOCAL/NODE=0

$ SET DISPLAY/CREATE/TRANSPORT=LOCAL/NODE=HUBBUB

Using the /TRANSPORT=LOCAL qualifier increases the performance of applications running and displaying on your system. Zero (0) is the standard shorthand notation for representing your system.

By default your own node is authorized to display on your system using either the LOCAL or DECNET transports, but not TCPIP. To authorize your own node using TCPIP, you must enter a zero (0) for the node name.

12.3 Running Applications from a DCL Command Line

Once you have directed your display to your workstation, you can run FileView and the desktop applications described in the DECwindows Motif for OpenVMS Applications Guide from another system by typing the following command lines at the DCL prompt ($):

To run this application	Enter this command
Bookreader	RUN SYS$SYSTEM:DECW$BOOKREADER
Calculator	RUN SYS$SYSTEM:DECW$CALC
Calendar	RUN SYS$SYSTEM:DECW$CALENDAR
Cardfiler	RUN SYS$SYSTEM:DECW$CARDFILER
Clock	RUN SYS$SYSTEM:DECW$CLOCK
CDA Viewer	VIEW/INTERFACE=DECWINDOWS filename
DECterm	CREATE/TERMINAL=DECTERM
EVE	EDIT/TPU/DISPLAY=DECWINDOWS
FileView	RUN SYS$SYSTEM:VUE$MASTER
Mail	RUN SYS$SYSTEM:DECW$MAIL
Message Panel	SYS$SYSTEM:DECW$MESSAGEPANEL
Notepad	RUN SYS$SYSTEM:DECW$NOTEPAD
Print Screen	RUN SYS$SYSTEM:DECW$PRINTSCREEN
Paint	RUN SYS$SYSTEM:DECW$PAINT
Puzzle	RUN SYS$SYSTEM:DECW$PUZZLE

For more information about adding qualifiers to the command lines that begin with the RUN command, see the DCL command descriptions in the OpenVMS User's Manual. For more information about adding qualifiers to the commands that start CDA Viewer, DECterm, and EVE, see the OpenVMS DCL Dictionary.

You can also use these command lines to run the desktop applications from DECterm or from FileView's DCL Command window on your workstation. To run multiple applications simultaneously from a single DECterm or FileView DCL Command window, add SPAWN/NOWAIT/INPUT=NL: to the beginning of each command line.