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?
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.
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.
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).
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 (very roughly) like this:
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.
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 😉
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 😉