Writing a logon procedure

Figure 1 shows a sample logon procedure. The statements specify the TSO/E-supplied TMP (IKJEFT01) for execution, and define the CLIST library, the work data sets for the assembler, and the assembler macro library, and specify that SYSIN and SYSPRINT are to be directed to the user's terminal.

Figure 1. Sample logon procedure

//AFPROC    EXEC    PGM=IKJEFT01,DYNAMNBR=20
//SYSUT1    DD      DSN=&SYSUT1,UNIT=SYSDA,SPACE=(1700,(400,50))
//SYSUT2    DD      DSN=&SYSUT2,UNIT=SYSDA,SPACE=(1700,(400,50))
//SYSUT3    DD      DSN=&SYSUT3,UNIT=SYSDA,SPACE=(1700,(400,50))
//SYSPROC   DD      DSN=CLIST.PROC.LIB,DISP=SHR
//SYSLIB    DD      DSN=SYS1.MACLIB,DISP=SHR
//SYSIN     DD      TERM=TS
//SYSPRINT  DD      TERM=TS

The only statement you must include in a logon procedure is an EXEC statement that identifies the TMP. You can only include one EXEC statement in each logon procedure. Logon procedure names (for example, AFPROC) must begin with A-Z; other characters can be alphanumeric. The name must not match that of any subsystem.

The TMP provided by TSO/E is named IKJEFT01. To use an installation-written TMP for a procedure, substitute the module name for IKJEFT01 in the PGM= operand in the EXEC statement. The following are additional operands you can use on the EXEC statement:

REGION: limits the address spaces of users who log on with this logon procedure.
DYNAMNBR: defines the number of data sets that can be dynamically allocated at the same time. A constant of 2 is always added to the DYNAMNBR value you specify. If DYNAMNBR= is omitted, the number of allocations is determined by the number of DD DYNAM statements. If DD DYNAM statements and DYNAMNBR= are both present, the number of concurrent allocations equals the combined total.
Using DYNAMNBR allows data sets to be more quickly reallocated because control blocks for data sets remain in storage, even after the data sets have been deallocated. You should choose the value for DYNAMNBR carefully. The value should be large enough so that it is not readily exceeded by the number of dynamic allocation requests made during the user's session. However, the larger the value you specify for DYNAMNBR the more virtual storage is used. The actual amount of virtual storage depends on the number of data sets the user allocates and deallocates in a session. The value cannot exceed the number of concurrently-allocated resources specified in the SYS1.PARMLIB member ALLOCxx, parameter TIOT SIZE. For details refer to . For more information about DYNAMNBR, see .
PARM: specifies a command, CLIST, or REXX exec to be interpreted as the first line of input from the terminal. The command, CLIST, or REXX exec is the first to execute after the user has logged on. For example, you could specify the name of a CLIST that allocates data sets required by the user.
Note: TSO/E does not execute a command the user enters in the COMMAND field of the logon panel if the command specified in the PARM field of the logon procedure fails. For example, a command the user enters will fail if TSO/E cannot find the command in the PARM field on the EXEC statement of the logon procedure.
TIME: provides job step timing. The value you specify overrides the default values you specified via JES initialization statements. You can use JES exits to override the job step timing for individual users. For more information about the JES initialization statements you can use, see either or . For more information about the JES exits you can use, see either or .