Wed, Jun
4 New Articles

ILE Activation Groups, Part 2

  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

In Part 1 we looked at activation group basics.  Now let's take a look at types.

Editor's Note: This article is excerpted from chapter 17 of 21st Century RPG: /Free, ILE, and MVC, by David Shirey.

Activation Group Types

If you set the DFTACTGRP parm to *NO (I want to be ILE), then another parm will miraculously appear on the compile command: the ACTGRP parm, which lets you set the type/name of the activation group that will be associated with this program. That is, this is where you tell the compile what activation group the program will run in and will be started (unless it already exists) when the program is kicked off. Let’s take some time and carefully go through each option.

Just so you know, one of the most important things to notice about each group is how it is ended. With OPM, the environment died when the program did (INLR on), but ILE is not that clear-cut because it wants to give you more control over what happens. In other words, ILE trusts you to make the right decision for your app. Oh, that’s so sweet. And yet, sad, oh so sad.


If *NEW is specified, then a new activation group will be created for this program when it is run. The name of that activation group will be assigned by the system and will be something weird and freaky.

As a result, if two people call the same program with a *NEW activation group, two differently named activation groups will be started.

If you specify *NEW on every compile, then every program will run in its own activation group and you will have essentially an OPM system. That is probably not what you want, but there are definitely times when *NEW is the right option.

On the positive side, this type of activation group is automatically ended when the program associated with this group ends. Thus, the cleanup is automatic and timely.

On the negative side, if you use *NEW for every program, then you will end up with a ton of activation groups that do not share, and you will be no farther along than if you were OPM.

*NEW is not available for service programs. Because they are always called from somewhere else and so, are not really “new.”


If a name is entered, one that you have made up, then this name will be used on the activation group. It is basically the same as *NEW except that you are specifying the name rather than letting the system do it, so it might be more intuitive to you. Or it may just be one more thing you have to think about.

Like *NEW, if you specify a specific name on every compile, then you will have essentially an OPM configuration.

The difference is in the end. Named activation groups will persist even after the program has ended. The theory is that if a program whose compile was pointed at this activation group starts up again, it can then grab that activation group and save the overhead of starting one up, so it makes sense if a program ends and restarts pretty regularly. The only way to get rid of one of these is to run a RCLACTGRP (Reclaim Activation Group) command. If you use this for a program that is used frequently, you might want to set up the RCLACTGRP for that name as part of the daily or weekly process. You really probably don’t want it to live forever.

One additional characteristic of the named activation group is that any global variables you are using in that program will also be visible (that is, usable) by programs in other named activation groups. Whether you think “hey, that is something handy” or “good grief, why did they allow that?” is up to you and says a lot about your personality. It could be either good or bad; just be aware that it can happen. Of course, if you have perfect ILE modules, you shouldn’t have any global variables.


In this case, the program compiled with this will use the activation group of the program that calls it.

Obviously, it makes no sense for *CALLER to be used on the first program in a sequence, but after that it makes lots of sense.

You will find that *CALLER is one of the more popular activation groups that you will use. If you are calling a series of programs in sequence, you might as well run all those programs together, you know, sharing resources and making like you are all friends and everything.

And since it does not really create its own activation group but just gloms you on to an existing one (either a *NEW or named), you don’t have to worry about ending it.

But *CALLER should only be used if the program you want to run was called by another program that set up an activation group first. If *CALLER is the first program in the sequence, then the program involved will end up running in the default activation group—something you don’t want.

And be careful with *CALLER with service programs. The idea of a service program is that it is called from a number of other programs (hopefully a large number), and the result of setting it up as *CALLER is to get a number of versions of it running in different activation groups, which wastes space and resources. You might be better off to set up your service programs to run in a single, named activation group even though you would have to run a RCLACTGRP regularly. It’s something to think about.


This is not the default activation group. The default activation group does not really have a name, it just sort of always exists, and in ILE we do not want to use it.

QILE is simply a name that IBM has assigned (hence the “Q”) to a named activation group, so that if you do not specify a name or *NEW or *CALLER, the program will fall back onto the QILE named activation group. In most compile commands, it is the default value assigned to the ACTGRP parm.

Using QILE still makes the program ILE (that is, determined via the DFTACTGRP parm being *NO, not based on the value in the ACTGRP parm). When a QILE group ends, you must use RCLACTGRP to do the reclaim (because it is really a “named” activation group). It won’t happen on its own as with *NEW.

Generally, using QILE is frowned upon by the cool kids. The main problem is that it is not very discriminating. That is, you might be using it, but it is also possible that some third-party software you are running might be using it, too. Now if you do a RCLACTGRP on QILE (after all, it is a named activation group) to recover your resources, you will also affect other applications that you might not want to have messed with.

The most important thing I want to remind you of is that you do not specify the activation group you want to use when you run the program. You assign it when you do your compile, so it will be the same every time the program runs until you recompile again. Don’t get confused by that.

What Happens When an Activation Group Closes?

So, we have some activation groups where the group goes away when the last program in that group sequence ends, and some activation groups which will live until you use the RCLACTGRP command. In addition, an activation group will go away if every program in that group fails.

But what actually happens when an activation group closes (because what happens will have a direct bearing on how we use them)?

  1. First, any files that are being used in the activation group will be closed.
  2. Second, any file overrides associated with those files will also
  3. Third, storage (both static and allocated) being tied up by that function will be
  4. Fourth, commitment control will end. That is, database changes will be committed if you are under commitment control (otherwise the changes will take place as they happen).

I don’t know about you, but all this is very exciting for me. But then I’m a real thrill seeker.


This is the command you will need to use to reclaim an activation group that does not end on its own.

As we said earlier, any activation group created with a user-defined name (“named”) or by using QILE will need to be deactivated manually by the RCLACTGRP command. It will not happen automatically.

This is a very simple command, just the name of the activation group you want to reclaim, plus an option for *NORMAL and *ABNORMAL.

*NORMAL does things in a civilized manner: committing any pending changes and sending a polite close notification message to any attached host systems.

*ABNORMAL just gets you the heck out of Dodge, and if someone gets hurt in the process, that’s their problem. It rolls back any uncommitted changes and sends a rather nasty and abrupt message to any attached host systems.

The command should only be used when the activation group is not in use.

There is an option for the activation group name to use, *ELIGIBLE, in which case the command will close all activation groups not currently running a job. Using this is not a good idea and should be avoided as it can result in your closing groups that you did not mean to (and which you have no control over, such as third-party groups).

As a parting shot, if you are used to using RCLRSC, stop it. Just stop it right now! It doesn’t work well in the ILE world, and you should be reclaiming resources by controlling your activation groups.

Stay tuned for Part 3, coming soon in an upcoming issue of MC RPG Developer. Can't wait?  You can pick up Dave Shirey's book, 21st Century RPG: /Free, ILE, and MVC, at the MC Press Bookstore Today!

David Shirey

David Shirey is president of Shirey Consulting Services, providing technical and business consulting services for the IBM i world. Among the services provided are IBM i technical support, including application design and programming services, ERP installation and support, and EDI setup and maintenance. With experience in a wide range of industries (food and beverage to electronics to hard manufacturing to drugs--the legal kind--to medical devices to fulfillment houses) and a wide range of business sizes served (from very large, like Fresh Express, to much smaller, like Labconco), SCS has the knowledge and experience to assist with your technical or business issues. You may contact Dave by email at This email address is being protected from spambots. You need JavaScript enabled to view it. or by phone at (616) 304-2466.

MC Press books written by David Shirey available now on the MC Press Bookstore.

21st Century RPG: /Free, ILE, and MVC 21st Century RPG: /Free, ILE, and MVC
Boost your productivity, modernize your applications, and upgrade your skills with these powerful coding methods.
List Price $69.95

Now On Sale



Support MC Press Online

$0.00 Raised:

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: