Articles

Parameters, category values and output options for the IBM i Work with System Values (WRKSYSVAL) command, including how to display…

Parameters, required OBJTYPE values, authority requirements and escape messages for the Retrieve Object Description (RTVOBJD) CL command, for use inside…

Look up RTVJOBA parameters for retrieving job name, user, library lists, output queue, print device, date format and CCSID into…

A parameter-level reference for OVRDBF: FILE, TOFILE, MBR, POSITION, SHARE, SEQONLY and OVRSCOPE, how stacked overrides resolve, and how DLTOVR…

A concrete, file-by-file GitHub Actions pipeline for ILE RPG: a self-hosted runner that reaches your IBM i over SSH, a…

A reference to the QSYS2 SQL services that cover job monitoring, PTF and group-PTF status, and ASP/storage capacity — the…

What SQLCODE -803 (SQL0803) means on Db2 for i, how to find the unique index or constraint and the row…

Worked, concrete examples of INNER JOIN, LEFT OUTER JOIN, and the IBM-i-specific EXCEPTION JOIN on Db2 for i, plus the…

A practical walkthrough of SQL DDL on Db2 for i: CREATE TABLE, PRIMARY KEY and FOREIGN KEY constraints, CHECK constraints,…

Field-level DDS keyword reference for display files: CHECK validity-checking codes, EDTCDE and EDTWRD numeric editing, and the COLOR and DSPATR…

How RPGLE locks a record on CHAIN and READ for an update file, the N extender that skips the lock,…

DCL-PR and DCL-PI syntax in free-form RPGLE: declaring parameters, the CONST, VALUE and OPTIONS keywords, EXTPROC and EXTPGM, and how…

Command-level reference for creating, changing, and deleting IBM i user profiles: CRTUSRPRF and CHGUSRPRF parameters and defaults, and the OWNOBJOPT/PGPOPT…

A symptom-first triage decision tree for IBM i: job stuck in MSGW, SQL error codes, lock waits, abends, and slow…

A tutorial on reading a physical or logical file from a CL program: declaring it with DCLF, reading records with…

A reference for declaring CL variables with DCL — *CHAR, *DEC, *LGL, *INT, *UINT, *PTR — and changing their values…

The skeleton every CL program is built on: PGM and its PARM parameter, DCL variable declarations, ENDPGM, and the two…

What SQLCODE -204 (SQL0204) means on Db2 for i, how naming mode, the library list, and the default schema decide…

What STRDBG (Start Debug) does, its twelve parameters and their defaults, how it opens the ILE source debugger, why UPDPROD(*NO)…

What SQLCODE -501 (SQL0501, 'Cursor &1 not open') means on Db2 for i, the causes IBM documents, how COMMIT, ROLLBACK,…

What SQLCODE -802 (SQL0802) means on Db2 for i, how to read IBM's documented error types (arithmetic overflow, division by…

What SQLCODE -913 (SQL0913) actually means on Db2 for i, why the preceding CPD6DEF diagnostic message matters, how WRKOBJLCK and…

SFLNXTCHG is a record-level, parameterless DDS keyword that forces a subfile record to be returned by the next READC (get-next-changed)…

A walkthrough of the expandable-subfile pattern: size SFLSIZ against IBM's 9,999-record hard limit, get control back at the last loaded…

How to build a load-all subfile in free-format RPGLE: sizing SFLSIZ far above SFLPAG, loading the full result set in…

The real DDS message-subfile pattern — SFLMSGRCD on the record format, a hidden SFLMSGKEY first field, and SFLPGMQ identifying the…

Syntax, parameters, return value and character-translation patterns for the RPGLE %XLATE built-in function, including case conversion and the predefined case…

Syntax, parameters, return value and validation patterns for the RPGLE %CHECK and %CHECKR built-in functions: finding the first or last…

Syntax, parameters, return type and edge cases for the RPGLE %REPLACE built-in function: replacing part of a string, inserting text,…

Syntax, the optional character-list parameter, return type and edge cases for the RPGLE string built-in functions %TRIM, %TRIML and %TRIMR.

How UPDSRVPGM replaces modules in a service program without rebuilding it, how DSPSRVPGM shows its modules, exports and signatures, and…

What CRTSRVPGM creates, how EXPORT decides the public interface, the parameters and defaults that matter, a tested example and the…

What CRTPGM binds into a program, how ENTMOD and ACTGRP choose the entry point and the activation group, the parameters…

What the CRTRPGMOD command creates, the parameters and defaults that matter, a working example, and what to do with the…

What CRTBNDRPG creates, why DFTACTGRP(*YES) is its default, the parameters that matter, and the two errors you meet when you…

The ACTGRP and DFTACTGRP values for CRTBNDRPG, CRTPGM and CRTSRVPGM, what an activation group holds, when one is deleted, and…

What a binding directory holds, the order in which the binder searches for exports, how RPGLE names one with BNDDIR,…

STRPGMEXP, EXPORT and ENDPGMEXP with their parameters, how service-program signatures are generated and checked, the rules for compatible changes, and…

The three RPGLE module types (cycle, MAIN and NOMAIN), what each can contain, how to export and import procedures and…

What an ILE service program is, how it differs from a program and a module, bind by copy versus bind…

A task-first IBM i command index for jobs, library lists, objects, spooled files, messages, subsystems, backup, security, and system maintenance.

Lookup WRKSPLF, WRKOUTQ, DSPSPLF, CHGSPLFA, HLDSPLF, RLSSPLF, DLTSPLF, HLDOUTQ and RLSOUTQ for IBM i printer output troubleshooting.

A practical lookup for WRKOBJ, DSPOBJD, CHKOBJ, DSPLIB, WRKLIB, WRKMBRPDM and DSPFD when finding IBM i objects, libraries and members.

Lookup DSPLIBL, ADDLIBLE, RMVLIBLE, CHGLIBL, EDTLIBL and CHGCURLIB, with examples for wrong-object and batch-versus-interactive library-list problems.

A safe runbook for an IBM i job in MSGW: find the inquiry message, inspect the job log, choose whether…

A practical lookup for WRKACTJOB, WRKJOB, DSPJOB, DSPJOBLOG, ENDJOB, HLDJOB and RLSJOB, with safe inspection versus job-changing actions.

Syntax, file usage keywords, which record UPDATE changes, the %FIELDS form, WRITE and duplicate keys, DELETE by key or after…

Syntax, read loops that end correctly, key-change behaviour of READE, backwards reading with READP and READPE, locks and what to…

Syntax, search arguments, where the file is left after SETLL and SETGT, the %FOUND and %EQUAL results, the existence test…

Where to find an IBM i job log, how to read a CPF message ID, which commands show message text,…

Syntax, the start and length rules, use on the left side of an assignment, and range behaviour for the RPGLE…

Free-form syntax and behaviour of the RPGLE control-flow opcodes IF, ELSEIF, SELECT, WHEN, DOW, DOU, FOR, FOR-EACH, LEAVE, ITER, RETURN…

Syntax, single and composite keys, %KDS, the no-lock extender, %FOUND handling and the CHAIN then UPDATE pattern for the RPGLE…

Syntax, start and length arguments, return values, case sensitivity and examples for the RPGLE built-in functions %SCAN and %SCANRPL, including…

Free-form syntax, result tests and examples for the RPGLE file operations CHAIN, READ, READE, READP, SETLL, SETGT, WRITE, UPDATE and…

Convert old RPGLE fixed-format calculation lines to free-form, opcode by opcode, with before and after pairs for arithmetic, loops, file…

Which RPGLE operation sets %FOUND, %EOF, %EQUAL, %ERROR and %STATUS, what each returns, and the edge cases that make a…

Syntax, return values and edge cases for the RPGLE array built-in functions %ELEM, %SIZE, %LOOKUP and its comparison variants, and…

A lookup of the RPGLE operation codes grouped by task, with the free-form statement to use in new code and…

Syntax, formats, return values and edge cases for the RPGLE date and time built-in functions %DATE, %TIME, %TIMESTAMP, %DAYS, %MONTHS,…

Syntax, rounding and truncation rules, return values and edge cases for the RPGLE numeric and conversion built-in functions %INT, %INTH,…

Syntax, parameters, return values and edge cases for the RPGLE string built-in functions %SUBST, %SCAN, %TRIM, %REPLACE, %LEN and %CHAR.

A lookup index of the RPGLE built-in functions you use most, grouped by task, with one-line syntax and links to…

Learn how RPGLE varying-dimension arrays grow within a declared maximum, when to choose *VAR or *AUTO, and how to guard…

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.

A practical IBM i maintenance plan: PTF types, HIPER and defective PTFs, checking what is installed, temporary versus permanent and…

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…

What Db2 for i is, how it is built into the operating system, how SQL and native file access map…

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

What Control Language does on IBM i: running commands, variables and flow control, handling errors with MONMSG, submitting jobs, and…

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

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…

How IBM i organizes everything as objects in libraries: object types, members in source and data files, the library list,…

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,…

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

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

Build an ILE RPG service program: NOMAIN source, binder language with STRPGMEXP, EXPORT and ENDPGMEXP, signatures and compatibility, CRTSRVPGM, UPDSRVPGM,…

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 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,…

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 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…

Schedule IBM i batch work with the base job scheduler: ADDJOBSCDE frequency, day and date parameters, omitted dates, hold and…

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…

How to order cumulative and group PTFs with SNDPTFORD, install them with GO PTF option 8 or APYPTF, deliver them…

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,…

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.