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HP OpenVMS System Management Utilities Reference Manual
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Alternatively, you can set up the port as a dedicated port for a special service on a LAT service node. See Example 2.

You can also create the port as a limited port, using the /LIMITED qualifier.

After creating a port, use the SET PORT command to associate (map) the port with a queue or a service. (See the discussion that follows Example 1.) Ordinarily, you create and set ports in the LAT site-specific startup procedure, LAT$SYSTARTUP.COM. For more details, see the HP OpenVMS System Manager's Manual.

Note
When using the CREATE PORT command to create an application port (for example, CREATE PORT LTA5001: /APPLICATION), you might receive an error message similar to the following one: 


%LAT-W-CMDERROR, error reported by command executor 
-SYSTEM-F-DUPLNAM, duplicate name

This error occurs because the LAT application port that you are trying to create has already been created by some other application. That other application could be LATCP itself because LATCP's port, LATCP$MGMT_PORT, is used to communicate with LTDRIVER.

You can avoid creating duplicate ports in two ways:

  • Use the SET NODE/DEVICE_SEED command to move the lower boundary of the device unit number range beyond the LTA devices that you are intending to use as application ports. (By default, LTA device units that originate from the $ASSIGN system service to LTA0: have unit numbers that fall within a range from 1 through 9999.) For example, if you know that all LTA devices from LTA7000: onward are not used as application ports, you could enter the following commands: 


    LATCP> SET NODE/DEVICE_SEED=7000
LATCP> CREATE PORT LTA5001:/APPLICATION
   .
   .
   .
LATCP> CREATE PORT LTA5010:/APPLICATION
    For more information, see the description of the /DEVICE_SEED qualifier in the SET NODE reference section.
  • Execute the LATCP command SET NODE/STATE=ON (either interactively or in a program) before any LTA application or dedicated ports are created. Because every LATCP management port (LATCP$MGMT_PORT) created by the previous LATCP invocation is deleted, no conflict exists with LAT application ports or newly created dedicated ports.
    For more information, see the description of the /STATE qualifier in the SET NODE reference section.

Examples

#1 

LATCP> CREATE PORT LTA22: /APPLICATION

This command creates an application port named LTA22: on a service node. You can associate the port with a specific printer on a terminal server (use the SET PORT /NODE /PORT command) or with a set of printers on a terminal server (use the SET PORT /NODE /SERVICE command). Or, you can associate the port with a dedicated port on a remote service node. In this case, use the SET PORT /NODE /SERVICE command, where the /SERVICE qualifier specifies an application service associated with a dedicated port on the remote node. See the examples for the SET PORT command.

#2 

LATCP> CREATE PORT LTA21: /DEDICATED

This command creates the LTA21: port. It will be used as a dedicated port that offers a specific service rather than a general timesharing service.

#3 

LATCP> CREATE PORT /LOG /APPLICATION -
_LATCP> /LOGICAL=(NAME=MAIL_PORT, TABLE=PROCESS, MODE=SUPERVISOR)

This command creates an application port. It assigns the name of the new port to the specified logical name (MAIL_PORT). The logical is created as a supervisor mode logical name in the LNM$PROCESS_TABLE logical name table. LATCP displays a confirmation message.

#4 

$ LCP :== $LATCP
$ LCP CREATE SERVICE/LIMITED ONLY_ONE
$ LCP CREATE PORT/LIMITED LTA1234:
$ LCP SET PORT LTA1234: /SERVICE=ONLY_ONE

This series of commands creates a limited service that allows only one user to log in to the system through that service. When a user connects to service ONLY_ONE by responding to the terminal server prompt (Local>), the user is assigned port LTA1234 and then prompted for the user name. Any user who attempts to connect to the same service while LTA1234 has a user logged in receives the "service in use" message.

CREATE SERVICE

Creates a service on a service node. You must have OPER privilege to use this command.

Format

CREATE SERVICE [service-name]

Parameter

service-name

Specifies a LAT service name. By default, a service name is the name of the local node you defined with the SET NODE command.

The service name can be from 1 to 16 ASCII characters in length. The characters allowed are as follows:

  • Alphanumeric characters: A--Z, a--z, 0--9
  • A subset of the international character set: ASCII codes 192--253
  • Punctuation characters: dollar sign ($), hyphen (-), period (.), and underscore (_)

Qualifiers

/APPLICATION

Specifies that the created service is an application service. An application service offers a specific application on the service node rather than a general interactive service. You can define a dedicated port for the service by using the CREATE PORT and SET PORT commands.

/IDENTIFICATION[="identification-string"]

Describes and identifies a service. Service nodes include the identification string in service announcements. A service node announces its services at regular intervals established with the SET NODE command. Entering the LATCP SHOW NODE command or the DECserver SHOW NODE command generates a display that includes this identification string. By default, the identification string is a translation of SYS$ANNOUNCE.

You cannot specify more than 64 ASCII characters in an identification string (a SYS$ANNOUNCE longer than that will be truncated to the first 64 characters). Enclose the string in quotation marks ("").

/LIMITED

Specifies that the service is a limited service, using devices assigned the limited characteristic and associated with (mapped to) this limited service. This qualifier is used in conjunction with the SET PORT /LIMITED command.

/LOG

/NOLOG (default)

Specifies whether LATCP displays a message confirming that the service was created. If you do not specify the /LOG or /NOLOG qualifier, the default is that no message will be displayed.

/STATIC_RATING=rating

/NOSTATIC_RATING

Enables or disables dynamic service ratings. A dynamic service rating means that a LAT algorithm calculates the availability of a service dynamically, based on the overall level of activity of the node that offers the service and the amount of memory. When a terminal server or node requests a connection to a service that is offered on two or more service nodes, the requesting node selects the service node with the highest (most favorable) service rating. This selection process is called load balancing.

The dynamic service rating, which is the default, is usually adequate for efficient load balancing on the LAT network. However, when necessary, you can use the /STATIC_RATING qualifier to disable dynamic service ratings so that you can specify a static (fixed) rating. That static rating value does not change until the dynamic service rating is reenabled.

Use the static rating to direct users away from or toward your node temporarily. Static ratings range from 0 to 255. Specify a low value to make the local service node less likely to be used; specify a high value to make the local service node more likely to be used.

If you do not specify either the /STATIC_RATING or /NOSTATIC_RATING qualifier, the default is that the LAT software uses the dynamic service rating.

Limited and application services do not rely exclusively on the dynamically calculated service rating. Instead, they use a portion of the dynamic rating based on how many ports are available for the service. For example, if a limited service has 50 percent of its ports available, the dynamic service rating will be scaled, halved, and then added to 105. When ports are available, the rating will always be above the value 105.

When all ports for a limited or application service are in use, the rating will be based on the scaled dynamic rating and the number of free queue slots on the local node. The rating will always be less than 90.

This rating procedure for limited and application services follows the terminal server rating algorithm for services and available ports that the service offers, while at the same time taking into account the availability of the node (which is the factor used to calculate the dynamic rating).

If your system is licensed for a specific number of units (where only a fixed number of users can log in to the system regardless of how the login limit is set), then all dynamic ratings become 0 when all OpenVMS license units have been consumed. (This forces all node service ratings to the lowest possible value when logins are not possible because all OpenVMS license units have been consumed.)

Note as well that the LAT software transmits a service announcement message when a user logs in to or out of the system. This allows the system to more quickly provide information about service rating changes that result from a login or logout operation.

Description

The CREATE SERVICE command creates a service that a service node offers to terminal servers (and nodes that support outgoing connections) on the LAT network. The service can be a general timesharing service that offers all the resources of the service node, or it can be an application service that offers a specific application on the service node. The number of services that you can create with the CREATE SERVICE command depends on the availability and capability of specific resources.

The following table lists the maximum number of services your node can offer and still be recognized by the DECserver terminal server, depending on the model number:

DECserver Terminal Server Maximum Number of Services
Offered by Node
Model 100 8
Model 200 64
Model 300 64
Model 90TL 64
Model 700 64
Model 500 127

Note
If you create more than the maximum number of services supported by a specific DECserver model, that server will not recognize your node.

To create an application service, use the /APPLICATION qualifier. In addition, define a dedicated port by using the CREATE PORT and SET PORT commands. Most often, a system manager creates services in LAT$SYSTARTUP.COM, the site-specific LAT configuration procedure. (For more information about creating an application service, see the HP OpenVMS System Manager's Manual. The OpenVMS I/O User's Reference Manual shows how to program an application service.)

Several service nodes can share one service name. A shared service name is especially useful in a cluster environment because it allows the cluster to be known by a single cluster name. When a user logs in, the terminal server connects to the least busy node offering that service.

You can modify the service characteristics with the SET SERVICE command.

Examples

#1 

LATCP> CREATE SERVICE/STATIC_RATING=195 SALES

This command creates the service SALES on a service node. This command assigns a static rating of 195 so terminal servers (and nodes that support outgoing connections) can assess the availability of services on the node.

#2 

LATCP> CREATE SERVICE/APPLICATION GRAPHICS

This command creates the service GRAPHICS on the local node. Use the CREATE PORT/DEDICATED and SET PORT/SERVICE=GRAPHICS commands to create a port that is dedicated to this service.

#3 

$ LCP :== $LATCP
$ LCP CREATE SERVICE/LIMITED ONLY_ONE
$ LCP CREATE PORT/LIMITED LTA1234:
$ LCP SET PORT LTA1234: /SERVICE=ONLY_ONE

This series of commands creates a limited service that allows only one user to log in to the system through that service. When a user connects to service ONLY_ONE by responding to the terminal server prompt (Local>), the user is assigned port LTA1234 and then prompted for the user name. Any user who attempts to connect to the same service while LTA1234 has a user logged in receives the "service in use" message.

DEFINE/KEY

Assigns a command string to a function key. For example, you can assign the LATCP command SHOW NODE to a function key.

Format

DEFINE/KEY key-name equivalence-string

Parameters

key-name

Specifies the name of the function key that you want to define. Valid key names are as follows:
Key Name LK201/LK401 Keyboards VT100-Type VT52-Type
PF1 PF1 PF1 Blue
PF2 PF2 PF2 Red
PF3 PF3 PF3 Black
PF4 PF4 PF4  
KP0-KP9 Keypad 0-9 Keypad 0-9 Keypad 0-9
PERIOD Keypad period (.) Keypad period (.)  
COMMA Keypad comma (,) Keypad comma (,)  
MINUS Keypad minus (-) Keypad minus (-)  
Enter Enter Enter Enter
FIND Find -- --
INSERT_HERE Insert Here -- --
REMOVE Remove -- --
SELECT Select -- --
PREV_SCREEN Prev Screen (LK201)
Prev (LK401) 		-- --
NEXT_SCREEN Next Screen (LK201)
Next (LK401) 		-- --
HELP Help -- --
DO Do -- --
F6-F20 F6-F20 -- --

equivalence-string

Specifies the command string that you want assigned to the function key. To preserve spaces and lowercase characters, enclose the string in quotation marks (" ").

Qualifiers

/ECHO

/NOECHO

Specifies whether LATCP displays the command string on your screen when you press the key. If you do not specify the /ECHO or /NOECHO qualifier, the default is that the command string will be displayed. You cannot use /NOECHO with the /NOTERMINATE qualifier.

/IF_STATE=state-name

Specifies the state that must be set (for example, the GOLD state) for the key definition to work. Lets you assign alternative meanings to keys when the specified state is set. See the discussion of the /SET_STATE qualifier. If you omit the /IF_STATE qualifier, LATCP uses the current state. The state name is an alphanumeric string. States are established with the /SET_STATE qualifier.

/LOCK_STATE

/NOLOCK_STATE

Specifies that the state set by the /SET_STATE qualifier remain in effect until explicitly changed. If you use the /NOLOCK_STATE qualifier, the state set by /SET_STATE remains in effect only for the next definable key that you press or for the next read-terminating character (such as Return or Ctrl/Z) that you type.

You can specify the /LOCK_STATE qualifier only with the /SET_STATE qualifier. If you do not specify the /LOCK_STATE or /NOLOCK_STATE qualifier, the default is that the state set by the /SET_STATE qualifier remains in effect until explicitly changed.

/LOG

/NOLOG (default)

Specifies whether LATCP displays a message confirming that the command was executed. If you do not specify the /LOG or /NOLOG qualifier, the default is that no message will be displayed.

/SET_STATE=state-name

Causes the specified state to be set when you press the defined key. The state name can be any alphanumeric string (for example, GOLD). Use the DEFINE/KEY/IF_STATE=state-name command to associate new meanings for keys when the specified state is set. See the example for the DEFINE/KEY command.

If you omit the /SET_STATE qualifier, the current state that was locked remains in effect.

/TERMINATE

/NOTERMINATE

Specifies whether the command string will be terminated (processed) when you press the function key. The default is /NOTERMINATE, which allows you to press other keys before the command string is processed. Pressing Return has the same effect as using /TERMINATE.

The /NOTERMINATE qualifier allows you to create key definitions that insert text into command lines, after prompts, or into other text that you are typing.

Description

The DEFINE/KEY command assigns a command string to a function key so that when you press that key, the command is executed.

Example


LATCP> DEFINE/KEY PF4 "SHOW NODE " /NOTERMINATE/SET_STATE=GOLD
LATCP> DEFINE/KEY PF4 "/ALL"/IF_STATE=GOLD/TERMINATE

The first DEFINE/KEY command in this example assigns the SHOW NODE command to function key PF4. To process the SHOW NODE command, you must press Return after pressing PF4. Note the space after the word NODE in the first DEFINE/KEY command. This space allows you to enter a node name after pressing PF4. When you press Return, the SHOW NODE command is processed. If the space is omitted, LATCP does not recognize the command (SHOW NODE). The state is set to GOLD; that state will be in effect for the next key that you press.

The second DEFINE/KEY command defines the use of the PF4 key when the keypad is in the GOLD state. When you press PF4 twice, the SHOW NODE/ALL command is processed.

DELETE LINK

Deletes a logical link from a node. You must have OPER privilege to use this command.

Format

DELETE LINK link-name

Parameter

link-name

Specifies the name of the link that you want to delete.

Use the SHOW LINK command for a list of the links that are defined for your node.

Qualifiers

/LOG

/NOLOG (default)

Specifies whether LATCP displays a message confirming that the link was deleted. If you do not specify the /LOG or /NOLOG qualifier, the default is that no message will be displayed.

Description

The DELETE LINK command stops any active sessions on the link and then deletes the link from your node.

Example


LATCP> DELETE LINK NETWORK_A /LOG

This command deletes the link NETWORK_A. The link was created with the CREATE LINK command.

DELETE PORT

Deletes a logical port from a node. You must have OPER privilege to use this command.

Format

DELETE PORT port-name

Parameter

port-name

Specifies the name of the application port or the dedicated port that you want to delete. An application port connects to a remote device on a terminal server, whereas a dedicated port connects to a special service.

Use the SHOW PORT command for a list of the application ports and the dedicated ports that are defined for your service node. You cannot use the DELETE PORT command to delete an interactive or forward LAT port.

Qualifiers

/LOG

/NOLOG (default)

Specifies whether LATCP displays a message confirming that the port was deleted. If you do not specify the /LOG or /NOLOG qualifier, the default is that no message will be displayed.

Description

The DELETE PORT command stops any active session on the port and then deletes the port from your service node.

Example


LATCP> DELETE PORT LTA27:

This command deletes the LTA27: application port. The port was created with the CREATE PORT command.

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