Document revision date: 19 July 1999

Using the SYSMAN commands PARAMETERS SET, PARAMETERS WRITE, and PARAMETERS USE enables you to modify active parameter values.

Modifying active values immediately affects dynamic parameters by changing their values in memory. Appendix C of the OpenVMS System Management Utilities Reference Manual identifies dynamic parameters, as does the SYSMAN command PARAMETERS SHOW/DYNAMIC. Values for nondynamic parameters cannot be changed while the system is running.

Modifying active values does not affect current values in the system parameter file on disk, because the next time you boot the system, the values on disk are established as the active values.

If you set new active parameter values and you want to use the new values for subsequent boot operations, write the new values to the current parameter file with the PARAMETERS WRITE CURRENT command, as shown in the Examples section.

Examples

1. The following example changes the LGI_BRK_TMO value to 300 in the work area, writes this change into memory as an active value, and displays the active value:

   SYSMAN> PARAMETERS SET LGI_BRK_TMO 300 SYSMAN> PARAMETERS WRITE ACTIVE SYSMAN> PARAMETERS SHOW LGI_BRK_TMO Node NODE21: Parameters in use: ACTIVE Parameter Name Current Default Minimum Maximum Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- LGI_BRK_TMO 300 300 0 -1 Seconds D Node NODE22: Parameters in use: ACTIVE Parameter Name Current Default Minimum Maximum Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- LGI_BRK_TMO 300 300 0 -1 Seconds D

2. The following example calls the current parameter values, including LGI_BRK_TMO, from disk to the work area, then displays LGI_BRK_TMO. In this example, the current value on disk is 600.

   SYSMAN> PARAMETERS USE CURRENT SYSMAN> PARAMETERS SHOW LGI_BRK_TMO Node NODE21: Parameters in use: CURRENT Parameter Name Current Default Minimum Maximum Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- LGI_BRK_TMO 600 300 0 -1 Seconds D Node NODE22: Parameters in use: CURRENT Parameter Name Current Default Minimum Maximum Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- LGI_BRK_TMO 600 300 0 -1 Seconds D

3. The next example writes the LGI_BRK_TMO value of 600 from the work area to memory, where it becomes the active value on the running system. Note that the command PARAMETER WRITE ACTIVE writes all the parameter values from the work area into memory, not just the value of LGI_BRK_TMO.

   SYSMAN> PARAMETERS WRITE ACTIVE SYSMAN> PARAMETERS USE ACTIVE SYSMAN> PARAMETERS SHOW LGI_BRK_TMO Node NODE21: Parameters in use: ACTIVE Parameter Name Current Default Minimum Maximum Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- LGI_BRK_TMO 600 300 0 -1 Seconds D Node NODE22: Parameters in use: ACTIVE Parameter Name Current Default Minimum Maximum Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- LGI_BRK_TMO 600 300 0 -1 Seconds D

Although it is not the recommended method, you can also use the System Generation utility (SYSGEN) to manage system parameters as follows:

Task	For More Information
Show parameter values	Section 14.8.2
Modify current values in the default parameter file	Section 14.8.3
Modify active values on a running system 1	Section 14.8.4
Create a new parameter file	Section 14.8.5

SYSGEN provides the commands shown in Table 14-4 for managing system parameters. Refer to the SYSGEN section of the OpenVMS System Management Utilities Reference Manual for detailed descriptions of SYSGEN commands.

Table 14-4 SYSGEN Commands Used with System Parameters

Command	Function
SHOW	Displays parameter values.
USE	Reads a set of values from memory or disk into a temporary work area for inspection or modification.
SET	Changes parameter values only in the work area; more permanent modification requires the WRITE command.
WRITE	Writes the content of the work area to memory or to disk.

For more information about the temporary work area, see the next section.

14.8.1 Understanding Parameter Values and SYSGEN

You should understand the different system parameter values explained in Section 14.1.1. Briefly, current values are stored in the default parameter file on disk. Active values are stored in memory and are used while the system is running. In addition to these values, SYSGEN writes a temporary copy into its own work area on disk. Figure 14-3 illustrates these different sets of values and shows how SYSGEN commands affect them.

Figure 14-3 SYSGEN Temporary, Active, and Current Parameter Values

In a typical session, you might display and change values in the following sequence:

1. Read values into SYSGEN's temporary work space with the USE command. USE ACTIVE reads in active values. USE CURRENT reads in current values.
2. Display the parameter values with the SHOW command.
3. Change a value with the SET command. (Note, however that the SET command only changes the value in SYSGEN's temporary work area.)
4. Make the change effective with the WRITE command:
   • WRITE ACTIVE writes the value to the set of active values in memory. (You can change an active value only if the parameter is a dynamic parameter.)
   • WRITE CURRENT writes the value to the set of current values on disk.

For a list of all the system parameters, refer to the OpenVMS System Management Utilities Reference Manual.

14.8.2 Showing Parameter Values with SYSGEN

To display values for system parameters, perform the following steps:

1. Invoke SYSGEN by entering the following command:

   $ RUN SYS$SYSTEM:SYSGEN

2. Enter the USE command to specify which values you want to display, as follows:

   To Display	Enter
   Active values	USE ACTIVE
   Current values	USE CURRENT
   Values from another parameter file	USE file-spec
   	For file-spec, specify the parameter file from which you want to display values; for example, USE SYS$SYSTEM:ALTPARAMS.DAT

3. Enter a SHOW command in the following format:

   SHOW [/qualifier] [parameter-name]

   
   Specify qualifiers to display parameters grouped by type. For example:

   To Display Values For	Enter
   The WSMAX parameter	SHOW WSMAX
   All dynamic parameters	SHOW/DYNAMIC
   All parameters in the TTY category	SHOW/TTY
   All parameters	SHOW/ALL

For more information about the SYSGEN SHOW command and qualifiers, refer to the SYSGEN section of the OpenVMS System Management Utilities Reference Manual.

Example

The following example uses SYSGEN to show the current values of all TTY system parameters:

$ RUN SYS$SYSTEM:SYSGEN SYSGEN> USE CURRENT SYSGEN> SHOW/TTY

Parameters in use: Current(1) Parameter Name Current Default Min. Max. Unit Dynamic -------------- ------- ------- ------- ------- ---- ------- (2) (3) (4) (5) (6) (7) TTY_SCANDELTA 10000000 10000000 100000 -1 100Ns TTY_DIALTYPE 0 0 0 255 Bit-Encode TTY_SPEED 15 15 1 16 Special TTY_RSPEED 0 0 0 16 Special TTY_PARITY 24 24 0 255 Special TTY_BUF 80 80 0 65535 Characters TTY_DEFCHAR 402657952 402657952 0 -1 Bit-Encode TTY_DEFCHAR2 135178 4098 0 -1 Bit-Encode TTY_TYPAHDSZ 78 78 0 -1 Bytes TTY_ALTYPAHD 2048 200 0 32767 Bytes TTY_ALTALARM 750 64 0 -1 Bytes TTY_DMASIZE 64 64 0 -1 Bytes D (8) TTY_CLASSNAME "TTY" "TTY" "AA" "ZZ" Ascii TTY_SILOTIME 8 8 0 255 Ms TTY_TIMEOUT 3600 900 0 -1 Seconds D TTY_AUTOCHAR 7 7 0 255 Character D SYSGEN>

SYSGEN displays the following information:

1. The values in use (in this example, current values)
2. The name of the system parameter
3. The value requested (in this example, the current value). The heading of this column is always "Current," regardless of whether it displays the current or active value of the parameter. In this context, "Current" refers to the value of this parameter currently in use, as specified by the USE command; it does not refer to the current value of the parameter stored on disk with the WRITE CURRENT command.
4. The default value
5. The minimum value
6. The maximum value
7. The unit of allocation
8. A "D," if the system parameter is dynamic

Example

The following example modifies the TTY_TIMEOUT parameter value in the VAX system parameter file:

$ SET DEFAULT SYS$SYSTEM $ RUN SYSGEN SYSGEN> USE CURRENT SYSGEN> SET TTY_TIMEOUT 3600 SYSGEN> WRITE CURRENT %OPCOM, 15-APR-1998 16:04:06.30, message from user SYSTEM %SYSGEN-I-WRITECUR, CURRENT system parameters modified by process ID 00160030 into file VAXVMSSYS.PAR SYSGEN> EXIT

14.8.4 Modifying Active Values with SYSGEN

Modifying active values immediately affects dynamic parameters by changing their values in memory. Appendix C of the OpenVMS System Management Utilities Reference Manual identifies dynamic parameters (as does the SYSGEN command SHOW/DYNAMIC). You cannot change values for nondynamic parameters while the system is running.

Modifying active values does not affect the current values in the system parameter file on disk. The next time you boot the system, the old current values are established as the active values.

If you set new active parameter values (by entering WRITE ACTIVE) and you want to use the new values for subsequent boot operations, you must write the new values to the current parameter file on disk by entering the WRITE CURRENT command, as explained in Section 14.8.3. If the parameters are not dynamic parameters, you must enter the WRITE CURRENT command and reboot the system.

When you change active parameters with SYSGEN, the operator communication manager (OPCOM) writes a message to the operator log and the operator console, unless you have changed the system message format with the DCL command SET MESSAGE.

Examples

1. The following example modifies the active value of the PFCDEFAULT parameter:

   $ SET DEFAULT SYS$SYSTEM $ RUN SYSGEN SYSGEN> SET PFCDEFAULT 127 SYSGEN> WRITE ACTIVE %OPCOM, 15-APR-1998 16:04:06.30, message from user SYSTEM %SYSGEN-I-WRITEACT, ACTIVE system parameters modified by process ID 00160030 SYSGEN> EXIT

2. The following example modifies the active value of the PFCDEFAULT parameter and also writes it to the Alpha system parameter file, so it will be used when the system reboots:

   $ SET DEFAULT SYS$SYSTEM $ RUN SYSGEN SYSGEN> SET PFCDEFAULT 127 SYSGEN> WRITE ACTIVE %OPCOM, 15-APR-1998 16:04:06.30, message from user SYSTEM %SYSGEN-I-WRITEACT, ACTIVE system parameters modified by process ID 00160030 SYSGEN> WRITE CURRENT %OPCOM, 15-APR-1998 16:04:06.30, message from user SYSTEM %SYSGEN-I-WRITECUR, CURRENT system parameters modified by process ID 00160030 into file ALPHAVMSSYS.PAR SYSGEN> EXIT

Creating a new parameter file has no effect on the running system. During a subsequent conversational boot operation, however, you can initialize the active system with the values of the new file.

How to Perform This Task

1. Invoke SYSGEN by entering the following commands:

   $ SET DEFAULT SYS$SYSTEM $ RUN SYSGEN

2. Enter a command in the following format to write a copy of a parameter file into SYSGEN's temporary workspace:

   USE file-spec

   
   where file-spec is the file specification for the parameter file to be used as a base. Modify the values in this file to create a new parameter file.

3. Enter commands in the following form to modify values as needed:

   SET parameter-name value

   
   where parameter-name specifies the name of the parameter to be changed, and value specifies the new value for the parameter.

4. Specify a command in the following format to write the values to a new parameter file:

   WRITE file-spec

   
   where file-spec is the file specification for the parameter file to be created.

5. Exit SYSGEN.

Examples

1. The following example creates a new version of the parameter file PARAMS.PAR with a new value for the TTY_TIMEOUT parameter:

   $ SET DEFAULT SYS$SYSTEM $ RUN SYSGEN SYSGEN> USE SYS$MANAGER:PARAMS.PAR SYSGEN> SET TTY_TIMEOUT 3600 SYSGEN> WRITE SYS$MANAGER:PARAMS.PAR SYSGEN> EXIT

2. The following example creates a file named SYS$SYSTEM:OURSITE.PAR, using the PARAMS.PAR file as a base:

   $ SET DEFAULT SYS$SYSTEM $ RUN SYSGEN SYSGEN> USE SYS$MANAGER:PARAMS.PAR SYSGEN> SET TTY_TIMEOUT 1000 SYSGEN> WRITE OURSITE.PAR SYSGEN> EXIT

With a conversational boot operation, you can modify the active parameter values in the following ways before the system boots:

Task	For More Information
Modify active values for individual parameters	Section 4.2.1
Initialize active values using values stored in a parameter file other than the default parameter file	Section 4.2.2
Reinitialize active values using default values	Section 4.4.1

At the end of the conversational boot, the default system parameter file is modified to store the new active parameter values.

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