JES3 (Job Entry Subsystem 3) is a component of the z/OS operating system that manages the flow of jobs and output in a mainframe environment. Unlike JES2, which operates primarily at the individual system level, JES3 provides more centralized control across multiple systems, with a global processor and local processors.
JES3 includes advanced features such as workload balancing, global resource control, and dependent job control. While IBM has announced that JES3 will eventually be discontinued, many organizations still rely on it, and a compatible replacement called JES3plus is available from Phoenix Software International.
| Feature | JES3 | JES2 |
|---|---|---|
| Command Prefix | Asterisk (*) | Dollar sign ($) |
| Architecture | Global/Local processors | Independent systems with shared spool |
| Resource Control | Centralized global control | More distributed control |
| Job Selection | Main Device Scheduling | Initiator-based selection |
| Command Structure | Verb-noun syntax (*I J) | Verb-operand syntax ($D J) |
JES3 commands begin with an asterisk (*) and typically follow a verb-noun structure. The basic format is:
1*verb [destination] noun,parameters
For example, to display job number 123: *I J 123
The destination field is required only when issuing commands to remote processors. By default, commands are processed on the global processor.
| Command | Description | Example |
|---|---|---|
| *I J | Display job information | *I J 123 - Display info for job 123 |
| *C J | Cancel a job | *C J=123 - Cancel job 123 |
| *F J | Modify job attributes | *F J 123,H - Hold job 123 |
| *F J | Release a held job | *F J 123,R - Release job 123 |
| *I U | Display output information | *I U J=123 - Display output for job 123 |
| *F U | Modify output attributes | *F U J=123,COPIES=2 - Change copies to 2 |
| *I S | Display job scheduler status | *I S - Display scheduler status |
| *I A | Display active jobs | *I A - Display all active jobs |
Commands for managing individual jobs:
12345*I J /* Display summary of all jobs */ *I J 123 /* Display information for job 123 */ *I J PAYROLL /* Display information for all jobs named PAYROLL */ *I J ALL,HOLD /* Display all jobs in hold status */ *I J ALL,ACTIVE=SYS1 /* Display all jobs active on system SYS1 */
1234*C J=123 /* Cancel job 123 */ *C J=PAYROLL /* Cancel all jobs named PAYROLL */ *C J=PAYROLL,CI /* Cancel and produce a dump */ *C J=123,DUMP /* Cancel and produce a dump (alternative syntax) */
12345*F J 123,H /* Hold job 123 */ *F J 123,R /* Release job 123 */ *F J 123,P=7 /* Change job priority to 7 */ *F J 123,CLASS=A /* Change job class to A */ *F J 123,SCHED=MAIN1 /* Change system affinity */
Commands for managing job output:
123456789*I U /* Display all output */ *I U J=123 /* Display output for job 123 */ *I U D=N1,T=PRT1 /* Display output for destination N1 on printer PRT1 */ *F U J=123,COPIES=3 /* Change number of copies for job 123 */ *F U J=123,DEST=N2 /* Change destination for job 123 */ *F U J=123,H /* Hold output for job 123 */ *F U J=123,R /* Release held output for job 123 */ *F U J=123,FORMS=SPEC /* Change forms to SPEC for job 123 */ *C U J=123 /* Cancel output for job 123 */
Commands for managing devices and controlling the system:
12345678910*X devname /* Start a device */ *V devname,ONLINE /* Vary a device online */ *V devname,OFFLINE /* Vary a device offline */ *I D D=devname /* Display device status */ *I D T=devtype /* Display status of devices of type devtype */ *I S /* Display scheduler status */ *F S,INT=interval /* Change scheduling interval */ *I A /* Display active jobs */ *I P /* Display processors */ *I GMS /* Display resource allocation */
Commands for managing job initiators:
123456*I G initname /* Display group initiator status */ *F G initname,ON /* Start initiator */ *F G initname,OFF /* Stop initiator */ *F G initname,PG=n /* Change group priority */ *F G initname,BAR /* Set job selection barrier */ *F G initname,NOBAR /* Remove job selection barrier */
Commands for controlling JES3 itself:
12345678*CALL JES3 /* Start JES3 */ *START /* Alternative to start JES3 */ *RETURN /* Stop JES3 (orderly) */ *CANCEL /* Stop JES3 (immediately) */ *X JES3CHECK /* Run JES3 spool integrity check */ *F Q,H /* Hold all jobs on input queue */ *F Q,R /* Release all jobs on input queue */ *I Q /* Display queues */
JES3 commands support various modifiers and parameters to refine their function:
| Parameter | Description | Example |
|---|---|---|
| H | Hold a job or output | *F J 123,H |
| R | Release a job or output | *F J 123,R |
| P=n | Set priority (0-15) | *F J 123,P=9 |
| CLASS=c | Set job class | *F J 123,CLASS=A |
| SCHED=main | Set system (main) for execution | *F J 123,SCHED=MAIN1 |
| COPIES=n | Set number of copies | *F U J=123,COPIES=3 |
| DEST=dest | Set output destination | *F U J=123,DEST=REMOTE5 |
| FORMS=form | Set output form | *F U J=123,FORMS=STD |
One of JES3's unique features is Dependent Job Control (DJC), which allows for sophisticated job dependencies:
1234567891011/* Display a DJC network */ *I N netname /* Hold a DJC network */ *F N netname,H /* Release a DJC network */ *F N netname,R /* Cancel a DJC network */ *C N netname
DJC networks are defined through JCL using the //*NET statement, creating dependencies between jobs.
1234567891011121314/* Step 1: Check for active jobs */ *I A /* Step 2: Get details about a specific job */ *I J 12345 /* Step 3: Hold the job to analyze it */ *F J 12345,H /* Step 4: Cancel the job if necessary */ *C J=12345 /* Step 5: Check if the job is gone */ *I J 12345
1234567891011121314/* Step 1: Check output for a job */ *I U J=12345 /* Step 2: Change output properties */ *F U J=12345,DEST=REMOTE2,COPIES=2 /* Step 3: Hold output if needed */ *F U J=12345,H /* Step 4: Release output when printer is ready */ *F U J=12345,R /* Step 5: Verify output status */ *I U J=12345
1234567891011121314/* Step 1: Check device status */ *I D T=PRT /* Step 2: Vary a device offline for maintenance */ *V PRT001,OFFLINE /* Step 3: Change device characteristics */ *F D PRT001,FL=FORMS1 /* Step 4: Bring device back online */ *V PRT001,ONLINE /* Step 5: Start the device */ *X PRT001
1234567891011121314/* Step 1: Display DJC networks */ *I N ALL /* Step 2: Display details of a specific network */ *I N PAYROLL /* Step 3: Hold a network before critical time period */ *F N PAYROLL,H /* Step 4: Release network when ready to run */ *F N PAYROLL,R /* Step 5: Monitor network progress */ *I N PAYROLL
With IBM's announcement that JES3 will eventually be discontinued, many organizations are considering migration options:
Write the JES3 commands to: (1) Display all jobs named PAYROLL, (2) Hold all PAYROLL jobs, (3) Change the class of job 1234 to A, and (4) Cancel job 5678 with a dump.
Write the JES3 commands to: (1) Display all output for job 1234, (2) Change the form to SPEC and copies to 3, (3) Hold the output, and (4) Release the output to printer PRT001.
Write the JES3 commands to: (1) Display the status of all printers, (2) Vary printer PRT002 offline, (3) Change PRT002's forms to INVCE, (4) Bring PRT002 back online, and (5) Start PRT002.
How JES3 processes and manages jobs globally
The language for controlling job execution
How batch jobs are processed on the mainframe
Managing resources across systems
Automating operations in mainframe environments
1. What prefix do JES3 commands use?
2. Which JES3 command displays information about a job?
3. What command would you use to cancel a JES3 job?
4. How would you release a job that is in hold status in JES3?
5. What is a unique feature of JES3 not found in JES2?