Mainframe Lab

Run JCL, read the spool, fix COBOL and query DB2 on a simulated z/OS system, in your browser. Free, no account needed.

• Your first job: back up a dataset
  Before tonight's payment run, your team lead asks you to keep a backup of the payment input file.
• Make a job safe to rerun
  EXTRACT ran last night but failed halfway and someone resubmitted it this morning. Now it fails straight away.
• Sort and filter payments with DFSORT
  The East region manager wants a file of approved (status A) East payments, largest first. The record layout is in the task panel.
• COBOL: count and total payments by status
  Finance wants a quick count of payments by status, and the total of approved ones.
• Incident: S0C7 in the overnight payment run
  PAYRUN abended overnight. The input PROD.PAY.DAILY comes from the branches and you may not edit it.
• Incident: the month-end extract runs out of space
  MTHEXT copies this month's transactions (LEARNER.FIN.TRANS, LRECL 200) into an extract. It ran fine for months, but tonight it abended.
• Incident: JCL error after a procedure change
  PAYRLD01 runs the production procedure PAYRLOAD from PROD.PROCLIB. You cannot change PROD.PROCLIB tonight. Make tonight's run load the production input safely.
• Incident: the nightly report never ran
  NIGHTLY is a three-step workflow: clean up, build the report file, print it. Last night was its first run after go-live. It ended RC=0008 and no report exists.
• Incident: unexpected RC 4 from the partner feed
  A partner moved to version 2 of their payment feed yesterday. FEEDRUN checks the feed with PAYCHK (which ends RC 4 if it rejects anything) and only posts it…
• DB2: answer three questions with SQL
  The branch team has three questions about the fictional customer database (schema LEARNER: CUSTOMER, ACCOUNT, TRANSACTION).