ABCs of z/OS System Programming Volume 3 - IBM Redbooks

The automatic class selection (ACS) routines (established by your storage administrator) and
the associated SMS classes eliminate the need to use many access method services
command parameters. The SMS environment is discussed in more detail in Chapter 5,
“System-managed storage” on page 239.
Invoking the IDCAMS utility program
When you want to use an access method services function, enter a command and specify its
parameters. Your request is decoded one command at a time; the appropriate functional
routines perform all services required by that command.
You can call the access method services program in the following ways:
► As a job or jobstep
► From a TSO session
► From within your own program
TSO users can run access method services functional commands from a TSO session as
though they were TSO commands.
For more information, refer to “Invoking Access Method Services from Your Program” in z/OS
DFSMS Access Method Services for Catalogs, SC26-7394.
As a job or jobstep
You can use JCL statements to call access method services. PGM=IDCAMS identifies the
access method services program, as shown in Figure 4-21.
//YOURJOB JOB YOUR INSTALLATION'S JOB=ACCOUNTING DATA
//STEP1 EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN DD *
/*
access method services commands and their parameters
Figure 4-21 JCL statements to call IDCAMS
From a TSO session
You can use TSO with VSAM and access method services to:
► Run access method services commands
► Run a program to call access method services
Each time you enter an access method services command as a TSO command, TSO builds
the appropriate interface information and calls access method services. You can enter one
command at a time. Access method services processes the command completely before
TSO lets you continue processing. Except for ALLOCATE, all the access method services
functional commands are supported in a TSO environment.
To use IDCAMS and certain of its parameters from TSO/E, you must update the IKJTSOxx
member of SYS1.PARMLIB. Add IDCAMS to the list of authorized programs (AUTHPGM). For
more information, see z/OS DFSMS Access Method Services for Catalogs, SC26-7394.
From within your own program
You can also call the IDCAMS program from within another program and pass the command
and its parameters to the IDCAMS program.
130 ABCs of z/OS System Programming Volume 3