z/OS Fundamentals · Interactive Series

Mainframe 101

Six articles, six interactive companions. Everything a student or early-career engineer needs to start finding their way around z/OS — from logging in, to writing code, to the network that keeps it all talking. Click through, drag sliders, and explore each topic hands-on.

The Series — 6 Parts
01
Mainframe Interaction
Keeping Up With The Mainframes
TSO/E ISPF USS TN3270
02
Introduction to Mainframe Programming Languages
Part One: Learning to Speak the Machine's Native Tongues
HLASM COBOL PL/I Java · Python · Go
03
Introduction to Mainframe Scripting Languages
Part Two: Automating the Machine's Everyday Work
REXX CLIST Shell / USS
04
Batch Processing and the Job Entry Subsystem (JES)
The Traffic Controller Behind Every Job
JCL JES2 / JES3 CICS
05
Designing and Developing Applications for z/OS
From Blueprint to Production
VSAM / Db2 IDz / Zowe DevOps
06
Mainframe Communications
The Portals Between Worlds
SNA / TCP-IP OSA / HiperSockets Security

Introduction to the Mainframe Workload Manager (WLM)

An earlier, standalone deep-dive on how WLM acts as the mainframe's traffic controller — translating business priorities into real-time resource allocation. Includes a live priority simulator and a zIIP CPU offload visualiser.

ZIA
Zubair Idris Aweda
Software Engineer · Technical Writer · Mainframe Open Education Mentee