AS400 history


Jan 29

I frequently see this question in places like Quora, and it’s both simple and complicated to answer. Simple because the AS/400 just doesn’t exist anymore. Complicated because, rather stupidly many current day programmers frequently call the IBM i System – “The AS400”.  Sounds crazy right?

Who uses the AS/400 anymore?

I doubt anyone is using the old AS400 machines anymore…. they are over thirty years old.

The good old AS400 comes from an era that was pre-internet, pre-mobile phones and pre-social media.  Yes, we all secretly yearn for those days, a disconnected nirvana of sorts, but owning an AS400 wont take us back in time (and I know because I have one in my living room) so lets get back on topic…. when floppy disks were sexy and a Giga-byte of storage was a distant dream.

AS400 HISTORY – my take on it anyway 😉

The AS400 ruled for years. But like all good things, it eventually needed an upgrade.

It’s successor, the IBM iSeries was used up until early 2000’s – this was really a re-branding along with some hardware upgrades. This line was sometimes called AS/400e and eServers but continued to run the branded OS/400 operating system.

In a half hearted attempt to clear the confusion the IBM System i re-branding also changed the name of OS400 to i5/OS (but many of the menus on the system still called it AS400) – so it’s easy to get confused.

AS400 history

The old AS/400 range was finally put to the bed with the launch of IBM POWER SYSTEMS – this hardware is hugely changed from the old AS400 machines.

Modern architecture means this range of IBM POWER SYSTEMS really doesn’t even compare to the old creamy AS400 boxes of old. Think of the changes in mobile phones in the last thirty years and this will give you idea of the ground shaking advances.

Modern IBM Power Systems are logically partitioned and can run multiple operating systems at once – arguably the most common is “IBM i” – this is a modern version of OS/400 (the operating system and database on the old *400* machines).

Thirty Years of System Evolution

  • 1988 AS/400 (Application System/400) running OS400
  • 1994 AS/400 (Advanced Series/400) running OS400
  • 2000 iSeries running OS400
  • 2004 System i running i5/OS
  • 2008 Power Systems running IBM i

Or in pictures it’s (roughly)  like this:

AS400 history 1
The IBM System 38 – before the IBM System 40 (aka AS400)

AS400 history 2
The IBM AS/400 is born. It’s big, creamy and like something out of Star Trek

AS400 history 3
As the AS400 evolved it got smaller and faster

AS400 history 4
The iSeries was way more powerful and a modern slinky new black shade

AS400 history 5
The IBM System i – was just a re-polished iSeries really… with some go faster stripes

AS400 history 6
bringing us to the current generation of IBM POWER systems running the beautifully slick IBM i operating system

Obviously #IBMi is hugely upgraded, with it’s main programming language (RPG) being upgraded so much it’s barely recognizable from the old RPG2 and logic cycle days. But the beauty of RPG is that you can still sit down today and write old fashioned 3 line RPG programs using the logic cycle if you wish.

IBM i is totally backward compatible and will still run programs written 20, 30, 40 years ago.

Better than that, RPG is alive and evolving with regular updates from IBM and the focus on modern free format style, vast list of API’s, Cloud based webservices and SQL server technology is engaging.

So why do some programmers still call this modern machine an old fashioned incorrect name?

To be honest – IBM’s poorly handled re-branding, confusing dilution of the brand and lack of marketing is the main culprit (imho of course).

But unfortunately, the system’s terrific backwards compatibility has spawned a whole generation of feckless grey-haired programmers who literally haven’t upgraded their programming skills for twenty years: They still write old fashioned code, don’t care to upgrade their programming knowledge and seem the enjoy the complexity and confusion inherent in maintaining source-code from decades back.

You can spot them because they’re invariably grumpy, exude a cleverer than though attitude, wear socks and sandals, use big button flip phones, never comment their code, don’t use social media (It’s too modern) and drive a car from the 80’s 😉

The AS400 is Dead – Long live IBM i

IBM i running on POWER SYSTEMS is the backbone of most big businesses out there today.

I’m typing this from Las Vegas where every casino and hotel is powered by IBM POWER SYSTEMS.

Next time you hear someone refer to their current IBM i System as “the 400” you can gently correct them 😉


About the Author

IBM i Software Developer, Digital Dad, AS400 Anarchist, RPG Modernizer, Alpha Nerd and Passionate Eater of Cheese and Biscuits. Nick Litten Dot Com is a mixture of blog posts that can be sometimes serious, frequently playful and probably down-right pointless all in the space of a day. Enjoy your stay, feel free to comment and in the words of the most interesting man in the world: Stay thirsty my friend.

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