Mainframe Universe

Free tutorials, interview Q&A, online tests & hands-on tools for mainframe technologies.

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600+ Tutorials 600 Exam Questions 4 Hands-on Tools 16 Q&A & Quiz Sets

Learn Mainframe

Step-by-step tutorials, module by module.

COBOL

The language of business computing.

JCL

Job Control Language essentials.

VSAM

Virtual Storage Access Method.

DB2

IBM's relational database.

CICS

Online transaction processing.

IMS

Hierarchical DB & transaction manager.

TSO

Time Sharing Option basics.

ISPF

Panels, editors & utilities.

MVS / z/OS

Operating system concepts.

REXX

Scripting for mainframes.

CLIST

Command lists under TSO.

QMF

Query Management Facility.

Endevor

Software change management.

ChangeMan

ZMF change control.

Abend Codes

Decode S0C7, S0C4, S322 & more.

Practice & Assess

Test yourself before the interview.

Interview Q&A

Real interview questions with answers.

8 sets · COBOL, JCL, VSAM, DB2

Online Tests

Timed exams with instant scoring.

30 exams · Basic, Intermediate, Expert

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Quick Quiz

Short quizzes for rapid revision.

Hands-on Tools

Practice right in your browser — no mainframe login needed.

COBOL Runner

Write & run COBOL programs online.

JCL Validator

Validate JCL syntax instantly.

DB2 Practice

Run real SQL on sample tables.

CICS Checker

Check EXEC CICS command syntax.

What's New

NEWAbend code guides14 visual guides: S0C7, S0C4, S322, S806 & more. NEW30 online exams10 topics × Basic, Intermediate & Expert levels. NEWPlayground toolsCOBOL runner, JCL validator, DB2 & CICS practice.

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