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DIF Commands from the PARMLIB DD Statement

When the commands are read via PARMLIB, no modify information, or subsystem character (#) should precede the DIF command. Only one command per line is allowed, and any line containing an asterisk in column one is considered to be a comment statement. A list of sample DIF commands follows:

* 
* DIF CONTROL CARDS FOR DTS SOFTWARE PRODUCTS
*
START ACC
ENABLE OPTION ACCVSAM
START SRS
ENABLE OPTION SRSVSAM
STATUS

Sharing the PARMLIB DD Statement

Conditional statement processing using SYSPARM

The SYSPARM statement is similar to the SYSID statement covered in the previous section. When a product reads input cards, a SYSPARM statement can be used to conditionally process the input records. Unlike the SYSID statement, SYSPARM is a variable that must be set before record input processing occurs.

A SYSPARM variable can be set:

• using the SYSPARM statement from the EXEC statement (local variable)
• using the DIF SYSPARM command to set or display either local or global SYSPARM variables. Global variables are saved in extended CSA.
• at run-time using a value obtained from another symbolic variable

Setting a SYSPARM Variable

The SYSPARM variable(s) can be local or global. A local variable is typically created using the SYSPARM keyword on the EXEC PARM statement for DIF or MONRUN JCL. However, any application that accepts parameters can use SYSPARM. The variables are saved at the job step level. For example, the following Monitor job sets a local SYSPARM to “BACK2”.

// EXEC PGM=MONRUN,PARM='SYSPARM=BACK2'    

By default, the variable name used to store the requested value has an internal name of $SYSPARM. However, alternate names can be created using the KEY keyword parameter. For example, the following statement creates the CMPNAME variable and sets the value to MP3000.

// EXEC PGM=MONRUN,PARM='SYSPARM=(MP3000 KEY(CMPNAME))'    

A global variable is stored in an extended CSA table and is created using the DIF SYSPARM command, which can be entered via the operator console, or as a command in one of the DIF PARMLIB DD files. Unlike local variables, global variables can be limited to specific products. Global variables can also be pooled into groups using the GLOBAL(group) parameter. The default group name defaults to SYSIN.

The following DIF console commands set and then display a global variable:

F DIF,SYSPARM SET DTSGVAR ABC
F DIF,SYSPARM GET DTSGVAR    

Accessing a SYSPARM Variable

A SYSPARM statement can be located in any input file that reads for control cards or rule statements. The SYSPARM command must start in column one. The values included or excluded on the SYSPARM command must be placed on one control card.

In most cases, input files use the most simple form of SYSPARM to access a local variable that was set using an EXEC PARM field. For example, when Monitor processes an input file, the following SYSPARM statement would establish a filter that only processes subsequent input cards if PARM='SYSPARM=MP3000' was specified on the execution JCL.

SYSPARM(INCLUDE(MP3000))
.
. statements in this section will be processed
.
SYSPARM(INCLUDE(ZPDTNC))
.
. statements in this section will NOT be processed
.
SYSPARM
.
. no conditional filtering - all statements processed    

To access a local variable that does not use the default $SYSPARM variable name, the KEY parameter can be used on the SYSPARM request. For example, to filter input cards based on CMPNAME equal to MP3000, use the following SYSPARM statement.

SYSPARM(INCLUDE(MP3000) KEY(CMPNAME))    

The SYSPARM statement can also access other symbolic fields to perform input filtering. If the KEY field specifies a variable name starting with “&”, the SYSPARM filter will process the key as a symbolic name. In the examples below, the SYSPARM statements filter input based on the day of the week using the &DAY:CURDATE to get the current day. In the first example, subsequent statements would only be processed on Sunday. The second SYSPARM filters statements for weekday processing.

SYSPARM(INCLUDE(SUNDAY) KEY(&DAY:CURDATE))
...
SYSPARM(EXCLUDE(SAT* SUN*) KEY(&DAY:CURDATE))
...    

If the DIF SYSPARM command was used to create a global variable, the input cards can access the extended CSA variable by using the GLOBAL parameter on the SYSPARM statement.

SYSPARM(INCLUDE(MP3000) KEY(CMPNAME) GLOBAL)    

If the DIF SYSPARM command specified an alternate group name on the global variable, the GLOBAL(group) form of the parameter can be used to access the variable. For example, if the F DIF,SYSPARM command created the CMPNAME variable in the FOO group, the following SYSPARM statement in the input records can access the variable.

SYSPARM(INCLUDE(MP3000) KEY(CMPNAME) GLOBAL(FOO))    

If there is a reason for SYSPARM not being coded in the PARM field, the following test can be used:

SYSPARM(INCLUDE(NULL))    

SYSPARM

DIF commands from the operator console

After DIF has been started, commands can be entered from a console by way of MODIFY (F) commands. The following commands would be used to refresh the ACC rules language, and show the current status of products started by DIF.

F DIF,REFRESH ACC
F DIF,STATUS    

The DIF subsystem character can also be used to enter commands from the console. The pound (#) is the default character, but the CMDCHAR parameter can be used to override the default subsystem character. The pound (#) is used in the same way as JES2 uses the dollar ($) character to denote commands. If you wish to disable the subsystem character and allow only the use of the MODIFY command, specify CMDCHAR=NONE in the parameter field in the DIF started task.

By using the subsystem character, an operator does not have to remember the started task name used by the MODIFY commands. To perform the same commands as above, an operator would enter the following commands on the console:

#REFRESH ACC
#STATUS    

DIF Commands from the DIF TSO command interface

By default, the DIF commands can only be entered from an operator console or via the PDS PARMLIB DD statement. The DIF TSO command interface can be enabled with the DIFTSO parameter in the DIF execution JCL. This parameter assigns a TSO command name to the interface. After the next DIF shutdown/restart, the TSO command processor can then be used to enter DIF commands. The output from the commands is returned to the TSO user.

For example, if DIFTSO=DIFTSO has been specified in the DIF execution JCL, the following status command can be issued from TSO after DIF is active.

DIFTSO STATUS    

DIF TSO commands under ISPF - The DIF TSO command processor is loaded into extended CSA, and the command is added to the MLPA chain. By default, ISPF will not execute the command from the ISPF command line. However, the DIF TSO command can be added to the ISPF command table, or the TSOEXEC command interface can be used from the ISPF command line. For example, the following command will issue the DIF STATUS command from an ISPF command line.

TSOEXEC DIFTSO STATUS    

ISPF DIFCMD authorization

DIF ISPF commands require authorization for the ISPF environment. Add the DIFCMD to the AUTHCMD NAMES section of the member IKJTSOxx in SYS1.PARMLIB to include the authorize DIFCMD usage.

The following steps are required to authorize the command:

1. 1. Locate the active IKJTSOxx PARMLIB Member

      To locate the current Parmlib library and member name, scan the system log for "MEMBER IKJTSO".

      For example, the following message was obtained using the TSO SDSF LOG command with a FIND "MEMBER IKJTSO" request.

      
      IEE252I MEMBER IKJTSO00 FOUND IN USER.PARMLIB
              

   2. Edit the IKJTSOxx PARMLIB Member

      Edit the IKJTSOxx member and add the DIFCMD entry to the AUTHCMD and AUTHPGM sections of the IKJTSOxx Parmlib member. After making the changes, save the member.

   3. Activate the modified IKJTSOxx member

      Issue the following SET command from a z/OS console to activate the updated IKJTSOxx member.

      For example:

      T IKJTSO=00         

   4. Add the DIF Load Library to the STEPLIB DD in the TSO Logon Procedure

      Ensure that the DIF load library is included in the TSO Logon Procedure used by the operations staff.

DIF Commands from the batch DIFCMD interface

DIF commands can also be issued using the DIFCMD interface. The following sample JCL executes the DIFCMD program to issue a DIF STATUS command to display the current status information about the started products followed by an SL command to display the service level information.

// EXEC PGM=DIFCMD
//STEPLIB DD DISP=SHR,DSN=DTS.R71.LOADLIB
//SYSPRINT DD SYSOUT=*
//SYSIN DD *
STATUS
SL    

Routing DIF Commands to Remote Systems

DIF commands can be routed to remote systems that are also running the DIF address space. The command output is returned to the issuing system.

There are two facilities to route DIF commands to remote systems:

• the DIF SYSPCMD command
• @defconn Interface

The SYSPCMD can be used to send DIF commands to all DIF started tasks running in a sysplex. This command is typically used when the PARMLIB is shared between the DIF started tasks in a sysplex, and a rules refresh can be issued to systems running DIF. The SYSPCMD interface is easy to use and requires no configuration. For more information, examine “SYSPCMD” on page 5-56.

The second method of remote command routing uses DEFCONN definitions and the @ command prefix character. This method does not require systems to belong to the same sysplex and uses TCP/IP to route command requests. Once the DIF systems are configured, a user on SYSA could issue the following STATUS command on SYSB:

F DIF,@SYSB STATUS
    

Before using the @ method for remote routing, the DIF started tasks must be configured to define the connections between systems. Two configuration changes are required to the DTS.R71.PARMLIB dataset(s) on the different systems:

1. Add the following statement to DTS.R71.PARMLIB(DIFINIT):

   
   INITOPT EXEC(CONNECTS(DIFCONN))
           

2. If necessary, create the DTS.R71.PARMLIB(DIFCONN) member and add the following DEFCONN entries with the appropriate IP address and port number.
   Note: Multiple entries can be used if the PARMLIB DD is shared between systems. Also, to avoid using userid and password parameters, examine “PassTicket Support (Optional)” on page 3-93 in the Rules Language Programming Guide. For more information about the following statements, examine “DEFCONN Command” on page 6-23.

   
   DEFCONN SYSA TCPIP(?.?.?.? 10)
   DEFCONN SYSB TCPIP(?.?.?.? 10)
   DEFCONN SYSC TCPIP(?.?.?.? 10)
           

Once the DIF address spaces have been restarted, the @ command interface can be used to route commands between systems.

Entering commands

To enter a command, type the desired command into the terminal or command prompt, and then press Enter.

DIF command table