Starting a system task from a console
Use the START command to start a system task from a console.
- The name or identifier is used on DISPLAY, MODIFY, RESET, CANCEL, FORCE, and STOP commands for the started task
- The job name or identifier is part of the RACF® resource name passed to the SAF interface
- The job name and member name are passed to a security product (such as RACF to give the task a user identification
- The job name is used in SMF records to identify the task.
- The job name specified in the JOBNAME= parameter of the START
The identifier specified on the START command.
- The job name specified on the JOB JCL statement within the member.
- The device number specified on the START command, or the device
number associated with the device type specified on the START command
The device number associated with the device type specified on the START command.
- The device number associated with the IEFRDER DD statement within the member.
- The member name.
IBM® recommends that you use the JOBNAME parameter rather than an identifier. If you use the JOBNAME parameter, SMF records, messages, and automated programs can reflect or react to job status; identifiers can only be viewed at a console.
- The 1 to 8 character name of a member of a partitioned data set that contains the source JCL for the task to be started. The member may be either a job or a cataloged procedure. The subsystem that selects the job determines which JCL procedure library is called, usually MSTR, JES2 or JES3.
- The name identifying the task to be started. This name can be
up to 8 characters long. The first character must be alphabetical.
If you omit an identifier and the started task does not have an IEFRDER
DD statement, the system uses the job name as the identifier.
If you omit an identifier and the started task has an IEFRDER DD statement, the device allocated to that started task becomes the identifier name.Note: The system allows multiple started tasks with the same membername and identifier to execute concurrently.
- The name that will be assigned to the job.
- If the source JCL is a procedure and you omit the JOBNAME keyword, the member name will be assigned as the job name.
- If the source JCL is a job and you omit the JOBNAME keyword, the system will use the job name assigned on the JOB statement in the JCL.
If you specify the JOBNAME keyword, the member name will be used only to identify the member that contains the JCL for the started task.
If you specify the JOBNAME keyword, you cannot specify identifier.
- An account number, and any other accounting information that your installation requires, such as
your department and room number.
The JOBACCT parameter specifies accounting data in the JCL JOB statement for the started task. If the source JCL was a job and already specified accounting data, the value specified on the JOBACCT parameter overrides the accounting data in the source JCL.
For a detailed description of the accounting information format and syntax rules, see z/OS MVS JCL Reference.
The length of acct_info cannot exceed 55 characters.
- The device type of the output device (if any) associated with
the task. Note: devicetype and devnum are mutually exclusive. You cannot specify both parameters on a START command.
- The device number of the device to be started. A device number
is 3 or 4 hexadecimal digits. A slash (/) must precede a 4-digit
number and is optional before a 3-digit number. Note: devnum and devicetype are mutually exclusive. You cannot specify both parameters on a START command.
- If devicetype is a tape or direct access device, the volume serial number of the volume mounted on the device.
- Program parameters passed to the started program. This might be a list in
parentheses or a string in single quotation marks. The documentation for the started program should
state which of the following techniques the program supports:
- The fourth positional parameter on the START command. The program uses the QEDIT macro to get access to this parameter.
- The PARM keyword value. Register 1 at entry to the started program points to it.
- The name of the subsystem that selects the task for processing.
The name must be one to four characters, defined in the IEFSSNxx parmlib
member, and the subsystem must be active. If SUB is
not specified, the primary subsystem, as specified in IEFSSNxx, will
select the task. Exception: If the name of the task being started is the same as that of a subsystem, the task will be started under the Master subsystem (MSTR). Then, because the only procedure libraries available to the Master subsystem are those specified in the MSTJCLxx's IEFPDSI data set, any procedures being started that are defined in the Job Entry subsystem's PROC00 data set but not in the MSTJCLxx data set, will be unavailable and will therefore not be found; the system will issue message IEFC612I.
When the task being started is a subsystem and you omit SUB, it is started under the master subsystem (MSTR) unless the subsystem itself asks to start under the Job Entry subsystem or the SSCTUPSS bit in the subsystem's SSCVT is on.
When you specify SUB, you override the subsystem's request as to the subsystem under which the task should be started.Note: Do not specify
SUB=MSTRunless the program specifically documents that it is supported. Using
SUB=MSTRin a situation where it is not supported will have ramifications on the proper execution of the program.
REUSASID=YESis specified on the START command and
REUSASID(YES)is specified in the DIAGxx parmlib member, a reusable ASID is assigned to the address space created by the START command. If
REUSASID=YESis not specified on the START command or
REUSASID(NO)is specified in DIAGxx, an ordinary ASID is assigned.
You can use
REUSASID=YESfor address spaces that result in message IEF352I ADDRESS SPACE UNAVAILABLE when they terminate. Before specifying
REUSASID=YES, ensure that the program being started supports running with a reusable ASID. Otherwise, specifying
REUSASID=YESmight result in system abend S0D3 . For more information about reusing ASIDs, see z/OS MVS Programming: Extended Addressability Guide.
- Any appropriate keyword parameter you specify to override the
corresponding parameter in the cataloged procedure. The maximum length
keyword=optionis 66 characters. No individual value within this field may be longer than 44 characters in length. You can specify:
- JCL JOB statement keyword parameters, to modify the JOB statement for the started task
- JCL EXEC statement keyword parameters, to override EXEC statements in the procedure being started (if the target of the START command is a procedure)
- JCL DD statement keyword parameters, to modify the IEFRDER DD statement (if it exists)
- JCL symbol names, to provide values for use in the started task
Parameters on JOB Statements
JOB statement keyword parameters are accepted for both started jobs and started procedures. For started jobs, the keyword specified on the START command overrides or nullifies the corresponding keyword in the source JCL.You can specify the following job-level keywords:
You cannot specify the following job-level keywords, unless you code them with no values (to nullify the same keywords in the source JCL):
The system ignores the following keywords when they are specified on the START command, unless you code them with no values (to nullify the same keywords in the source JCL):
- CLASSNote: For a started task:
- In a JES2 environment the system ignores the CLASS keyword.
- In a JES3 environment the system ignores all CLASS related attributes and functions except for device fencing, SPOOL partitioning, and track group allocation. For more information about CLASS attributes and functions, see z/OS JES3 Initialization and Tuning Guide.
Parameters on EXEC StatementsEXEC statement keywords that have the same name as JOB statement keywords (for example, COND, REGION, and TIME), are treated as JOB statement keywords.Note:
- If you specify an option that must have lower case characters, enclose it within apostrophes.
- If you specify an option within apostrophes, for
'DUMMY', use the correct case letters within the apostrophes. START command processing does not convert lower case characters to uppercase. Thus, entering lower case letters might cause a JCL error or an abend. Similarly, entering upper case letters where lower case is required (in z/OS UNIX System Services, for example) may cause incorrect results.
- If you are overriding a data set name in the cataloged procedure
and the name of the data set is 44 characters long, use
DSN=name. If you specify
DSNAME=name, the START procedure stops and returns message IEF640I.
- If you need information on started task considerations or use of overrides and symbols, see z/OS MVS JCL Reference.