HP OpenVMS System Manager's Manual, Volume 2:...

Managing System Parameters

Managing System Parameters with SYSMAN

Modifying System Parameters with a Conversational Boot

Managing System Parameters with SYSGEN  

HP recommends that you use AUTOGEN to modify system parameters. For more information, see Modifying System Parameters with AUTOGEN. If for some reason you cannot use AUTOGEN, HP recommends that you use SYSMAN. For more information, see Managing System Parameters with SYSMAN.

Task	For More Information
Show parameter values	Showing Parameter Values with SYSGEN
Modify current values in the default parameter file	Modifying the System Parameter File with SYSGEN
Modify active values on a running system1	Modifying Active Values with SYSGEN
Create a new parameter file	Creating a New Parameter File with SYSGEN

SYSGEN provides the commands shown in SYSGEN Commands Used with System Parameters for managing system parameters. Refer to the SYSGEN section of the HP OpenVMS System Management Utilities Reference Manual: M--Z for detailed descriptions of SYSGEN commands.

Table 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.

Understanding Parameter Values and SYSGEN  

You should understand the different system parameter values explained in Default, Current, and Active Values. 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. SYSGEN Temporary, Active, and Current Parameter Values illustrates these different sets of values and shows how SYSGEN commands affect them. 

Figure 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 HP OpenVMS System Management Utilities Reference Manual.

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 HP OpenVMS System Management Utilities Reference Manual: M--Z.

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> 

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

Modifying the System Parameter File with SYSGEN  

Parameter values modified with the System Generation utility (SYSGEN) will be overridden by the AUTOGEN command procedure. To keep parameter modifications made with SYSGEN, edit the file SYS$SYSTEM:MODPARAMS.DAT as explained in Controlling AUTOGEN's Parameter Settings with MODPARAMS.DAT to specify the new parameter values.

Although you can modify system parameter values with SYSGEN, HP recommends that you use AUTOGEN. For more information, see Modifying System Parameters with AUTOGEN. If you cannot use AUTOGEN, HP recommends that you use the System Management utility (SYSMAN) to modify system parameters. For more information, see Managing System Parameters with SYSMAN.

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-2000 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 

Modifying Active Values with SYSGEN  

Parameter values modified with SYSGEN will be overridden by the AUTOGEN command procedure. To keep parameter modifications made with SYSGEN, edit the file SYS$SYSTEM:MODPARAMS.DAT as explained in Controlling AUTOGEN's Parameter Settings with MODPARAMS.DAT to specify the new parameter value.

Although you can modify system parameter values with SYSGEN, HP recommends that you use AUTOGEN or the System Management utility (SYSMAN). For more information, see Managing System Parameters with SYSMAN.

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 Modifying the System Parameter File with SYSGEN. 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-2000 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-2000 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-2000 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 with SYSGEN  

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-specwhere 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 valuewhere 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-specwhere file-spec is the file specification for the parameter file to be created.
5. Exit SYSGEN.

Parameter values modified with SYSGEN are overridden by the AUTOGEN command procedure. To keep parameter modifications made with SYSGEN, edit the file SYS$SYSTEM:MODPARAMS.DAT as explained in Controlling AUTOGEN's Parameter Settings with MODPARAMS.DAT to specify the new parameter values.

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

1	Applies only to the dynamic system parameters.

( Number takes you back )

Managing System Parameters with SYSMAN

Modifying System Parameters with a Conversational Boot