Getting Started with RPG (and Coffee)

 The RPG Blend – Real Code, Real Coffee, No Nonsense

Today’s coffee? A bold cup of Green Mountain Dark Granite—rich, full-bodied, and exactly what you need when diving into something new. Grab a coffee warmer or your favorite Yeti mug, and let’s get started.

If you're here, you're curious about RPG—or you're tired of hearing “IBM i isn’t going anywhere” without knowing why. Let’s fix that. This post is your practical starting point—just enough caffeine and code to get you going.

Step 1: Sign Up for a Free PUB400 Account

To write and test RPG code, you’ll need access to an IBM i system. PUB400.com offers exactly that—for free.

Here’s how to get started:

  1. Visit https://pub400.com
  2. Click on “Request a User ID.”
  3. Fill out the form and wait for your credentials via email (usually within a day).
  4. You now have access to a real IBM i system.

Once you’re in, you’ll be able to use tools like the green screen (5250 terminal) to interact with the system.

Step 2: Learn the Basics of IBM i

Before diving into RPG code, take a few minutes to get familiar with the IBM i environment:

Key Concepts:

  • Library Lists: Think of libraries like folders. A library list defines what data and programs you can see and use.
  • Source Physical Files: Where your RPG source code lives. These are objects that contain members—each member is a source file.

·         Objects: Everything on IBM i is an object—programs, files, libraries, queues. Use DSPOBJD to display information about objects.

·         Message Queue: Each user has a message queue where the system sends notifications or messages from jobs. Use DSPMSG to view them.

  • Commands (CL): Much of what you do on IBM i is driven by commands. Example: WRKMBRPDM to work with source members.

Common Commands to Try:

  • WRKLIBL – Work with your current library list.
  • CHGLIBL – Change your library list.
  • DSPLIBL – Display your current library list.
  • WRKMBRPDM – Work with source members in a source physical file.
  • WRKSPLF – View your spooled files (print output).
  • WRKOUTQ – See the contents of output queues.
  • WRKACTJOB – Check current running jobs and system activity.
  • DSPMSG – View system messages for your session.
  • STRPDM – Start the Program Development Manager tool to access source files and utilities.

Pro Tips:

  • MSGW (Message Wait): A job status where a program is waiting for user input—usually seen on WRKACTJOB. Investigate and respond using WRKMSG.
  • LCKW (Lock Wait): Indicates a job is waiting for a resource that is locked by another job.
  • IFS (Integrated File System): A part of IBM i that acts like a traditional file system, allowing you to store and access stream files like PDFs, CSVs, and more.

Try It:

Log in using a 5250 emulator and run each command above. It’s old-school, yes—but understanding this layer is key.This may feel old-school, but understanding this layer is key to becoming effective on the platform.  These commands give you hands-on experience navigating the system. Try them out to build confidence before writing your first program.

Step 2.5: Create Your Own Development Library and Source Files

Before you start coding, it’s a good practice to create your own development space on the system. This gives you full control over your programs and avoids messing with shared or public libraries.

Note:
When your account is created on PUB400, default development libraries—typically matching your user ID (e.g., GEORGE, GEORGELIB, or similar)—are automatically created for you.

Step-by-Step: Create Your Dev Library and Source Files

Let’s assume your username is GEORGE. You’ll create:

  • A library: GEORGEDEV
  • A source file for RPGLE: QRPGLESRC
  • A source file for CL: QCLSRC

1. Create Your Development Library

CRTLIB LIB(GEORGEDEV) TEXT('GEORGE DEVELOPMENT LIBRARY')

2. Create Source Physical Files

CRTSRCPF FILE(GEORGEDEV/QRPGLESRC) RCDLEN(112) TEXT('RPGLE SOURCE')

CRTSRCPF FILE(GEORGEDEV/QCLSRC) RCDLEN(112) TEXT('CL SOURCE')

3. Add Your Library to the Top of Your Library List

ADDLIBLE LIB(GEORGEDEV) POSITION(*FIRST)

This ensures your programs compile into your personal library and not into a system or shared one.

4. Verify Your Library List

DSPLIBL

Make sure GEORGEDEV is at the top.

Step 3: Write Your First RPG Program

Let’s start with something simple.

Use WRKMBRPDM to open or create a source member:

WRKMBRPDM FILE(GEORGEDEV/QRPGLESRC) 

 

Create a new member HELLO using F6 or the command below.

 

STRSEU SRCFILE(GEORGEDEV/QRPGLESRC) SRCMBR(HELLO) TYPE(RPGLE) text(‘HELLO WORLD’)

Use SEU to enter this code:

**free

DCL-S msg VARCHAR(50) INZ('Hello, RPG World!');

dcl-s response char(1) inz;    

 

DSPLY msg ‘ ‘ response;

 

*INLR = *ON;

 

Press F3 to exit and save.

What’s Happening Here:

  • **free
    This tells the compiler you're writing in fully free-form RPG. No column restrictions, just clean code like modern languages.
  • DCL-S msg VARCHAR(50) INZ('Hello, RPG World!');
    • DCL-S declares a standalone variable.
    • msg is the name of the variable.
    • VARCHAR(50) means it can hold up to 50 characters.
    • INZ(...) initializes it with the value 'Hello, RPG World!'.
  • DCL-S response char(1) inz;
    • DCL-S declares a standalone variable.
    • msg is the name of the variable.
    • CHAR(1) means it can hold up to 1 character.
    • INZ(...) initializes it with the value one blank.
  • DSPLY msg ‘ ‘ response;

o    This is a quick way to display the contents of the msg variable on the screen. Think of it like print() in Python or console.log() in JavaScript. 

o    The ‘ ‘ is a parameter maker for message queue (msgq).

o    Declares a one-character variable called response initialized with a blank. The program waits for user input before ending.

  • *INLR = *ON;
    This ends the program and ensures it releases resources properly. It’s like cleaning up before you exit.

Compile and Run:

  1. Compile it using CRTBNDRPG:

CRTBNDRPG PGM(YOURLIB/HELLO) SRCFILE(YOURLIB/QRPGLESRC)

  1. Run it:

CALL YOURLIB/HELLO

You should see your message on the screen.



That’s your first RPG program. Clean, simple, and working.

Step 4: Set Up VS Code for RPG Development

SEU and PDM are classic, but modern RPG deserves modern tools. VS Code makes it easier to write, edit, and explore code from your own machine.

What You Need:

1.      VS Code installed: https://code.visualstudio.com/

2.      IBM i Extensions:

o    Code for IBM i

Step-by-Step:

1. Install “Code for IBM i”

Open VS Code > Extensions (Ctrl+Shift+X) > Search for Code for IBM i > Install

2. Configure Your PUB400 Connection

·         Open the Command Palette (Ctrl+Shift+P) > IBM i: Add Connection

·         Host: pub400.com

·         User ID and Password: from your PUB400 email

·         The port for pub400 is 2222

3. Set Your Working Library

After logging in, set your working library to GEORGEDEV.

4. Open Your Source Files

Browse your libraries and open members inside QRPGLESRC. You can edit RPGLE code in a clean, modern editor with syntax highlighting.

Why Use VS Code?

·         Free-form RPG is easier to write without column limitations

·         Better syntax highlighting and error checking

·         Push changes directly to IBM i

·         Integrated terminal, Git support, and extensions

Step 5: Create a “Hello World 2” Program Using VS Code

Now that you’ve connected VS Code to PUB400, let’s write and run your second RPG program—this time using your modern IDE.

1. Launch VS Code and Connect

  • Open VS Code
  • Open the Command Palette (Ctrl+Shift+P)
  • Type: IBM i: Connect to an IBM i
  • Choose your PUB400 connection (or create one if you haven’t yet)
  • Wait for the status bar to show you’re connected

You’ll see your user ID in the lower-left corner when connected.

2. Navigate to Your Source File

  • In the IBM i Projects sidebar:
    • Expand GEORGEDEV
    • Find QRPGLESRC
    • Right-click → NEW MEMBER…
      • Name: HELLO2
      • Type: RPGLE
      • Description: Hello World 2

This creates a source member directly in the IFS and opens it in the editor.

3. Write the Program

Paste this into the open editor tab:

**free

DCL-S msg VARCHAR(50) INZ('Hello again, RPG from VS Code!');

DCL-S response char(1) inz;

DSPLY msg ‘ ‘ response;

*INLR = *ON;

Click Save (Ctrl+S)

4. Compile the Program

  • Click Compile (Ctrl+E)
  • Choose CRTBNDRPG from the options

If successful, the output panel will confirm that the program object HELLO2 was created in your GEORGEDEV library.

5. Run It from VS Code

1.      Hover over the PUB400 connection in the bottom status bar of VS Code.

2.      Select Terminals → 5250 Emulator.

3.  Sign in, then run: CALL GEORGEDEV/HELLO2

You’ll see the display output directly in the 5250 emulator window.



Why This Matters

Writing RPG in VS Code avoids the 1980s column restrictions. You get:

  • Modern editing experience
  • Syntax highlighting
  • Compile-on-save capability
  • Seamless access to PUB400

VS Code + IBM i makes legacy tech feel current again.

 

Final Sips

You don’t need to be a mainframe wizard. You just need curiosity, some time, and a decent cup of coffee.

While much of your early IBM i exploration happens in the "green screen" terminal, not everything is locked in the past. IBM i is a rock-solid platform, but it’s not stuck in time. With tools like VS Code and RDi, you can bring the power of RPG to the modern developer workflow—one cup at a time.

Modern RPG development gives you:

·         A clean, readable syntax with fully free-form RPG

·         Tools like VS Code and RDi that rival any modern IDE

·         A platform that balances stability with flexibility

So yes—learn the green screen basics. Understand how the system works. But know that powerful, productive, and modern development is right at your fingertips.

Want to explore the code without copying it from the article?
Check out the full source files on GitHub: https://github.com/Zero-Sub/the-rpg-blend

Coming Up Next…

In the next post, we’ll go hands-on and build a real RPG program that reads data from a file. We'll introduce input, output, and writing business logic the RPG way.

Until then:

·         Sign up for PUB400

·         Build your dev library

·         Explore the system

·         Install VS Code

·         And sip slow—your RPG journey just began.

 

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