Articles

Learn how fixed-size RPGLE arrays use DIM, one-based subscripts, and %ELEM to store and process ordered values safely.

Use RPGLE LEAVE and ITER correctly: exit a loop immediately, skip the rest of the current iteration, and keep loop-control…

Learn how pre-test RPGLE DOW loops evaluate their while-condition before the body runs, why the body can execute zero times,…

Learn how post-test RPGLE DOU loops run their body first, evaluate the until-condition at ENDDO, and guarantee at least one…

Learn how counted RPGLE DO loops initialize an index, repeat a controlled block, advance through an inclusive limit, and avoid…

Learn how RPGLE comparison operators and AND/OR logic build boolean conditions, how precedence and grouping actually work, and how to…

Learn how RPGLE guard clauses and early exits can flatten nested conditions, expose the main path, and make procedure logic…

Learn how RPGLE SELECT, WHEN, OTHER, and ENDSL express readable multi-branch decisions, with ordered evaluation and practical business examples.

Learn how RPGLE IF, ELSEIF, ELSE, and ENDIF choose one-way, two-way, and ordered decision paths through practical business examples.

Learn what RPGLE's default (reference-style) parameter passing, VALUE, and CONST actually do to caller storage, with before/after worked examples and…

Learn how to use the Db2 for i MERGE statement to update matching rows and insert new rows in one…

Learn the difference between an RPGLE variable, a named constant, and a literal, and how to use DCL-C, character/numeric/typed literals,…

Learn RPGLE data structure basics: declare typed subfields, use QUALIFIED access, reuse layouts with LIKEDS, and read simple nested structures.

Use RPGLE character, decimal, integer, date/time, and indicator types correctly by understanding what each declaration's length and precision mean.

Declare RPGLE variables with DCL-S, and see how scope and storage type - automatic, static, and working storage - control…

Organize fully free-form RPGLE with consistent sections, spacing, indentation, continuations, and comments that make program flow easier to review.

Learn how RPGLE indicators and status flags control legacy program flow, and how to map many patterns to clearer fully…

Learn how legacy RPGLE C-specs express calculations and control flow, then map those responsibilities to clear, fully free-form RPGLE logic.

Beginner guide to traditional RPGLE input and output specifications, their relationship to records and fields, and the modern fully free-form…

Beginner guide to RPGLE compiler directives, the **free directive, ctl-opt, and program-wide control options.

Beginner guide to the major sections of a typical RPGLE program and why each section exists.

Beginner guide to clearer RPGLE names, cleaner ordering, and easier-to-maintain code.

Beginner guide to reading RPGLE source in the right order.

Beginner guide to RPGLE editing tools and the edit, compile, diagnose, run workflow.

Beginner guide to the three RPGLE source styles you will see in IBM i code.

Beginner guide to how RPGLE source becomes a compiled IBM i program object.

Beginner guide to RPGLE terminology on IBM i.

Beginner-friendly RPGLE pillar for IBM i.

REST APIs and HTTP clients let IBM i exchange business data with modern systems while keeping the core logic controlled…

JSON and XML processing let IBM i exchange structured data with modern systems without forcing the core logic to change…

Good IBM i error handling turns a vague failure into a message, a log entry, and a clear recovery path.

Modules, bound programs, and binding directories are the packaging layer that turns compiled IBM i code into reusable application components.

Prevent IBM i resource leaks and job restarts by mastering activation groups, call stacks, ACTGRP settings, and a practical RPG,…

Good IBM i application design separates concerns, keeps business logic readable, and makes change safer for the whole team.

Security auditing and authority collection help IBM i teams see how access is used in practice and where permissions should…

Release upgrades succeed when compatibility, testing, and rollback planning are treated as first-class work.

PTF management is the routine discipline that keeps IBM i systems current, stable, and less surprising over time.

Access Client Solutions is the modern client toolkit many IBM i users rely on for sessions, SQL work, file transfer,…

The Integrated File System is how IBM i works with stream files and directories in a way that looks familiar…

Data areas, data queues, and user spaces give IBM i programs simple building blocks for sharing state and passing messages.

A practical look at why IBM i remains relevant in 2026, including stability, integrated architecture, and long-lived business value.

Output queues and spool files are the IBM i print and report pipeline, even when the final destination is not…

A practical guide to IBM i security basics, including authorities, object protection, and simple best practices.

Subsystems and job descriptions are the operational framework that decides where work runs and how jobs are classified on IBM…

Journaling and commitment control are the pieces that help IBM i applications protect data changes and recover cleanly after failures.

A practical IBM i career path starts with the basics, then grows into development, operations, database work, and broader platform…

A beginner-friendly explanation of Db2 for IBM i and why the database layer is so tightly integrated with the platform.

Good IBM i maintenance is about managing change safely: source control, review, testing, documentation, and predictable releases.

A practical introduction to CL programming on IBM i, including what it is used for and why it matters in…

SQL on IBM i is the modern way to query and manage Db2 for i data. Beginners can start with…

A beginner-friendly introduction to RPGLE on IBM i, including what it is, why it is still used, and how to…

Performance tuning on IBM i starts with measurement, workload understanding, and small changes that improve real bottlenecks.

IBM i batch work runs on schedules, queues, and jobs. Understanding that flow helps beginners see how the platform handles…

A practical introduction to the IBM i object model, including libraries, objects, members, and how they are used every day.

Debugging on IBM i starts with logs, messages, and the right tools. Beginners can learn to isolate problems without guessing.

A beginner-friendly explanation of the IBM i architecture, including the operating system, integrated database, objects, and the server layer.

IBM i organizes data through libraries, files, members, and SQL access. Understanding those layers makes the platform much easier to…

IBM i and mainframe systems both support serious enterprise workloads, but they are different platforms with different operating models, scale…

Modernizing IBM i does not mean replacing the platform. It usually means exposing existing systems through APIs, SQL, better interfaces,…

Master IBM i message queues and CL error handling in 2026: create message files with CRTMSGF and ADDMSGD, send informational…

A short history of the AS/400 platform lineage and how it evolved into the IBM i environments that run on…

Master DB2 for i stored procedures in 2026: create SQL procedures with CREATE PROCEDURE, define IN, OUT, and INOUT parameters,…

Call external REST APIs from IBM i in 2026: use QSYS2.HTTP_GET and QSYS2.HTTP_POST SQL table functions to make HTTP requests,…

AS400 is the common historical name, while IBM i is the current operating system. This article explains what each term…

Master ILE RPG service programs in 2026: compile RPG modules with CRTRPGMOD, create service programs with CRTSRVPGM, export and import…

Master IBM i save and restore in 2026: save and restore individual objects with SAVOBJ and RSTOBJ, save entire libraries…

AS400 usually means IBM i running on IBM Power hardware. This beginner's guide explains AS/400, IBM i, and IBM Power…

Master DB2 for i triggers in 2026: create BEFORE and AFTER triggers with CREATE TRIGGER, use FOR EACH ROW and…

Master IBM i commitment control in 2026: start and end commitment definitions with STRCMTCTL and ENDCMTCTL, control DB2 transaction scope…

Master IBM i job scheduling in 2026: add recurring batch jobs with ADDJOBSCDE, manage schedules with WRKJOBSCDE and CHGJOBSCDE, create…

Build AI-driven anomaly detection for IBM i operational data in 2026: query QSYS2 system views for job and performance metrics,…

Secure the IBM i Integrated File System (IFS) in 2026: manage stream file and directory authorities with CHGAUT and WRKOBJAUT,…

Integrate IBM MQ with IBM i in 2026: create and configure queue managers, define local and remote queues, set up…

Master IBM i output queue and print management in 2026: create and configure output queues with CRTOUTQ and CHGOUTQ, work…

Master DB2 for i common table expressions (CTEs) and recursive SQL in 2026: use the WITH clause to name intermediate…

Master ILE RPG string handling on IBM i in 2026: use %SCAN, %SUBST, %REPLACE, %TRIM, %TRIMR, and %TRIML for text…

Configure and troubleshoot IBM i TCP/IP networking in 2026: use CFGTCP to manage interfaces and routes, add IP addresses with…

Apply the strangler fig pattern to IBM i modernization in 2026: identify seams in monolithic RPG applications, build a facade…

Build a production REST API server on IBM i in 2026 using Node.js and Express in PASE: connect to DB2…

Read and write IFS stream files from ILE RPG programs on IBM i in 2026: use Qp0lOpen, Qp0lRead, Qp0lWrite, and…

Master IBM i data areas and data queues for inter-program communication in 2026: create and manage data areas with CRTDTAARA,…

Master DB2 for i window functions in 2026: use ROW_NUMBER, RANK, DENSE_RANK, NTILE, LAG, LEAD, FIRST_VALUE, and LAST_VALUE with the…

Master ILE RPG date and time handling in 2026: declare date, time, and timestamp fields, convert between formats using %DATE…

Bring AI inference to IBM i in 2026 with IBM watsonx on Power: deploy Granite foundation models co-located with your…

Tune IBM i memory performance in 2026: understand the *BASE, *INTERACT, and *SPOOL shared pool structure, set pool sizes and…

Send email from IBM i in 2026 using every available method: configure the SMTP server with CHGSMTPA, send plain-text alerts…

Automate IBM i batch jobs in 2026: add recurring schedule entries with ADDJOBSCDE, manage and monitor schedules with WRKJOBSCDE, set…

Unlock the power of DB2 for i CTEs and recursive SQL in 2026: write readable multi-step queries using the WITH…

Master IBM i RPG subfile programming in 2026: design subfile and subfile control record formats in DDS with SFLPAG and…

Secure the IBM i Integrated File System in 2026: understand the IFS authority model, control *PUBLIC access, use CHGAUT and…

Master IBM i journal management in 2026: create journals and journal receivers with CRTJRN, start and end object journaling with…

Modernize fixed-format RPG on IBM i using AI tools in 2026: convert with CVTRPGSRC and IBM Merlin, use LLMs like…

Implement OAuth 2.0 authentication from IBM i in 2026: the client credentials flow using HTTPAPI and DB2 HTTP functions, storing…

Optimize DB2 for i query performance in 2026: understand SQE vs CQE query engines, use Visual Explain in ACS to…

Build robust IBM i CL programs with proper exception handling: IBM i message types, MONMSG command patterns, program message queue…

Master ILE RPG data structures: dcl-ds syntax, qualified data structures with dot notation, LIKEDS for cloning a structure, template data…

Understand the IBM i PASE runtime in depth: AIX binary compatibility, how PASE differs from QShell, managing environment variables, PASE…

Set up a modern IBM i development environment in 2026: install the Code for IBM i VS Code extension, edit…

A complete guide to IBM i work management in 2026: create custom subsystem descriptions, configure routing entries and class objects,…

Learn how to integrate IBM i with Microsoft Azure in 2026 using the Azure Python and Node.js SDKs in PASE.…

A comprehensive guide to DB2 for i JSON and XML functions in 2026: extracting scalars with JSON_VALUE, shredding arrays with…

A deep dive into the IBM i ILE binding model: how modules, programs, service programs, and binding directories relate, how…

Master IBM i CL exception handling in 2026: message file architecture, CRTMSGF and ADDMSGD to define messages, SNDPGMMSG for escape…

A practical guide to IBM i security hardening in 2026: QSECURITY levels 10–50, auditing user profiles with QSYS2.USER_INFO, removing excessive…

A comprehensive guide to DB2 for i SQL stored procedures and user-defined functions in 2026: CREATE PROCEDURE syntax, IN/OUT parameters,…

A practical guide to using AI and large language models to document legacy IBM i RPG programs in 2026: extracting…

A complete guide to IBM i system startup and shutdown procedures in 2026: understanding the IPL sequence, configuring QSTRUP, starting…

HTTPAPI by Scott Klement is the standard open source library for making outbound HTTP calls from IBM i RPG programs.…

DB2 for i triggers fire automatically on INSERT, UPDATE, and DELETE, enforcing rules that application code cannot bypass. This post…

A complete guide to RPGUnit for ILE RPG in 2026: install the framework, write test cases and test suites for…

A practical IBM i application modernisation roadmap for 2026: compare six strategies from screen transformation and API wrapping to selective…

Vector search and text embeddings bring semantic search to IBM i in 2026 — converting DB2 for i text fields…

DB2 for i replication in 2026 is built on IBM i journals — the same journal receivers that underpin HA…

A hands-on guide to connecting IBM i with Apache Kafka in 2026 — running kafkajs and confluent-kafka-python producers in PASE,…

A practical guide to IBM i display files in 2026 — DDS syntax, CRTDSPF, RPG EXFMT screen I/O, subfile programming…

IBM i PTF management in 2026 spans four distinct fix types — individual PTFs, cumulative PTF packages, SF99xxx group PTFs,…

IBM i high availability and disaster recovery in 2026 requires understanding the full stack: geographic mirroring at the storage layer,…

Python runs natively on IBM i in PASE with direct DB2 access via ibm_db and pyodbc, IBM i program calls…

The IBM i OS API layer accessible from ILE RPG: QCMDEXC for running CL commands at runtime, the list API…

Advanced IBM i IFS topics for production environments: enabling journalling on IFS directories for recovery and replication, sharing IFS directories…

The operational CL commands IBM i administrators use every day: WRKACTJOB status codes explained (RUN, DSKW, LCKW, MSGW), CHGJOB and…

Advanced DB2 for i query performance: the SQE versus CQE split and what it means for your queries, column statistics…

IBM i performance problems are almost always paging (undersized memory pools) or SQL without indexes. This post covers the IBM…

Node.js runs natively on IBM i in PASE with direct in-process access to DB2 for i via idb-connector and to…

AI intersects with IBM i in three ways: as an integration target (calling OpenAI or watsonx from RPG and SQL…

The IBM i Integrated File System is the foundation of modern IBM i development — Git, open-source packages, Node.js, Python,…

IBM i security is object-based and OS-enforced — bypassing the application does not bypass security. This post covers QSECURITY levels,…

DB2 for i is not a database running on IBM i — it is part of the operating system. This…

Modern RPG is not the fixed-format column-dependent code that gave the language its reputation. This post covers fully free-format RPG…

CL is not a legacy language waiting to be replaced — it is the correct tool for controlling the IBM…

IBM i can integrate with Azure, AWS, and SaaS platforms without custom adapters or protocol gymnastics. This post covers five…

IBM i has collected detailed performance data for decades — most shops only look at it when something breaks. This…

IBM i DevOps is not theoretical — Git, Bob, RPGUnit, and GitHub Actions all run on IBM i 7.3+. This…

REST APIs are the bridge between IBM i and modern front ends. This post covers every practical option — IAS…

The "should we leave IBM i?" conversation has been happening for twenty years. The shops that handled it well are…

Most IBM i shops still manage source the same way they did in the 1990s — members in source physical…

IBM i batch jobs are the ones nobody watches — until one fails. This post covers SBMJOB, WRKJOBSCDE, job queues,…

Every RPG developer eventually writes a program that does something it should not. The calculation is wrong. The loop runs…

Most RPG programs are written to handle the happy path. The file exists, the record is found, the calculation succeeds,…

IBM i has a reputation for being secure. That reputation is earned — the security model is granular, well-designed, and…

Performance problems on IBM i tend to fall into a small number of categories. A query that reads every record…

Every IBM i developer eventually ends up doing some administration. A job gets stuck. The output queue fills up. A…

IBM i has been talking to other systems for decades. EDI over AS/400 communications, FTP file drops, MQ message queues…

Most IBM i developers spend their entire careers working with physical files and never touch the IFS. That is understandable…

Every physical file you have ever defined in DDS, every CHAIN and READ in your RPG programs, every logical file…

If you write RPG, you already use CL whether you realise it or not. Every time you submit a job,…

You already know how to read files with READ and CHAIN. They work. But the moment your query involves a…

Subprocedures let you break logic into reusable blocks inside a single program. Service programs take it further — compile your…

You already write RPG. Free-format does not replace what you know — it removes the straitjacket. No more counting columns,…

A practical enterprise guide to IBM i modernization covering APIs, RPG transformation, AI-assisted modernization, and legacy system evolution.