AS400 is Extinct, iSeries is Dead – Long Live “IBM i” 

 March 5, 2012

By  NickLitten

This has been an ongoing argument disagreement in our IBM i and RPG programmer communities for well over a decade: Should IBM have changed the name when the launched the replacement for the old AS/400 computer? Many people using the latest IBM i servers still enjoy calling it “the 400” but the big problem with this is that non-technical people (often management) hear this and then think they are still using the huge old fashioned pre-internet computer system of yesteryear.

A simplified history of The AS400

Hardware: The AS400 was a minicomputer system introduced in the 1980’s. In the 1990’s it was replaced by the iSeries system. In the 2000’s the iSeries was replaced by the System i. The System i was replaced by the current IBM Power System.

Software: Operating system has evolved and been rebranded with each new system hardware upgrade — from OS400, thru I5/OS to the current grandchild of the old OS400 operating system called IBM i.

I like to describe this as:

  • Generation 1 – AS400 (running OS400 operating system)
  • Generation 2 – iSeries (running OS400 operating system)
  • Generation 3 – System i (running i5/OS operating system)
  • Generation 4 – Power System (optionally running the IBM i Operating system)

<RANT> For some hugely frustrating reason, there is still a sizable group of IBM i Software Developers who insist on referring to the latest and greatest IBM i Power machine by the incorrect name of it’s twenty year old predecessor. This machine is NOT an AS400. It is not “THE 400”. It’s not even an iSeries. The AS400 is an old computer system from the last century! The AS400 hardware could not run the modern operating systems we use. The AS400 was invented before the advent of email, before facebook, Hell… it was around before the internet! Calling IBM POWER SYSTEMS an AS/400 is insulting and automatically puts the picture of an old legacy computer system into our users heads. Not good. When a new model of a computer is released with brand new hardware and a different name (to differentiate it from the old model) use the correct name. I just don’t understand this resistance against the new machines branding. As I.T. Professionals surely it’s the information technology that fires us up. Surely it’s the excitement of modern computers that wakes us up every morning? We are all IT Professional, surely that makes us all Star Trek Nerds, which in turn means we all understand that “Resistance is Futile!” šŸ˜‰  </RANT>

Anyway, back on topic of the AS400 -> iSeries -> System i -> Power System upgrade discussion

IBM Power Servers are NOT the same as the old IBM AS400 servers

Last night, I was reading a frustrating discussion on Linkedin about this very subject. Filled with stubborn headed programmers who learned to program years ago and then.. amazingly… stopped learning and decided to stick with what they knew and try to freeze the natural evolution of the machine and the programming language. The core of the conversation goes like this:

[thrive_text_block color=”blue” headline=”Some Old Bloke”]I heard from one of my old customers from the 1990’s and my software is still running on their 400 – bloody good machines these iSeries boxes[/thrive_text_block]

[pullquote align=”right” cite=”Modern Programmer”]Cool! But I wouldn’t think they are still using the old iSeries hardware. Probably on a more recent IBM Power System running the IBM i operating system[/pullquote]

[thrive_text_block color=”blue” headline=”Some Old Bloke”]Huh? Well whatever it is – I call it the AS400[/thrive_text_block]

[pullquote align=”right” cite=”Modern Programmer”]Sorry again, it’s not an AS400 — that’s an even older machine — this is IBM i running on a Power System[/pullquote]

[thrive_text_block color=”blue” headline=”Some Old Bloke”]You can call it whatever you like, but I’m calling it an AS400[/thrive_text_block]

[pullquote align=”right” cite=”Modern Programmer”]ā€‹*sigh*[/pullquote]

The AS400 was a great machine in its time. It’s replacement, the IBM iSeries was even better.

IBM i has evolved even further since then and calling the current range of IBM Servers AS400’s is more than simply wrong it’s confusing the audience and implying that your business is running on a twenty year old Server– this means our end customers think of it as an old fashioned legacy machine. But its not… aaargh!

Angus the IT Chap regularly rants about this topic and he decided to use a picture rather than a thousand words:

as400 used to be a cool machine years ago
IBM i on Power is the coolest server of the 21st century


IBM i Software Developer, Digital Dad, AS400 Anarchist, RPG Modernizer, Shameless Trekkie, Belligerent Nerd, Englishman Abroad 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 remember: If at first you don't succeed then skydiving probably isn't a hobby you should look into.

Nick Litten

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