Beginner7 min readLesson 3 of 4
SDSF: watching the system
SDSF is the panel where you find your job, read its output, look at what is running, and issue operator commands if you are allowed. If you learn one z/OS tool early, learn this one.
The commands worth memorising on day one
| Command | Shows you |
|---|---|
| ST | Status of all jobs — queued, running, and finished output |
| DA | Active address spaces right now, with CPU use |
| H | Held output queues |
| O | Output queues ready to print |
| I | The input queue — jobs waiting to run |
| LOG | The system log — the running commentary of the whole system |
| PREFIX x* | Filter to jobs whose name starts with x |
| OWNER userid | Filter to one user's jobs |
SDSF STATUS DISPLAY ALL CLASSES LINE 1-3 (3) COMMAND INPUT ===> ST SCROLL ===> CSR NP JOBNAME JobID Owner Prty Queue C PAYRUN01 JOB09341 VSAHA1 1 PRINT X PAYRUN02 JOB09342 VSAHA1 1 EXECUTION GLPOST20 JOB09287 BATCHID 1 PRINT X Type S beside a job and press Enter to read its output.
Reading job output in the right order
Job output is several sections stacked together. Read them in this order and you will diagnose most failures quickly:
- JESMSGLG — the system's account of the job: when it started, each step's return code, and any abend.
- JESJCL — your JCL after the system expanded it, including everything a PROC contributed. This is where you see what actually ran, not what you thought you wrote.
- JESYSMSG — allocation messages. Dataset not found, space failures and security violations show up here.
- SYSOUT / SYSPRINT — your program's own output, including COBOL DISPLAY statements and utility reports.
Other things you will do here
- Cancel a job — type
Cbeside it (permission required, and think first in production). - Purge output — type
Pto clear finished output off the spool. - Watch a long job — from
DA, sort by CPU to see what is consuming the machine. - Find a message in the log — from
LOG, useFINDto search for a job name or message ID.
Common mistakes
Reading SYSOUT first
Program output rarely explains an allocation or security failure. Start with JESMSGLG, then JESYSMSG.
Only reading the last error
Errors cascade. The first non-zero step is usually the real cause; everything after it is fallout.
Cancelling in production without checking
Cancelling mid-update can leave files half-written. Know the restart procedure before you cancel anything.
What you will see at work
- You will live in SDSF. Set PREFIX and OWNER once at the start of your session and your view stays useful all day.
- Many sites restrict operator commands in SDSF by RACF. Not seeing an option usually means you lack authority, not that it is missing.
- When you send someone job output, send JESMSGLG and JESYSMSG too — not just SYSOUT. It saves a round trip.
Key terms
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