Recently saw an AS/400 on Facebook Marketplace. I was very tempted to pick it up, but I am trying to reduce AND knew dang well I would have no idea how to interact with the thing.
I recall in about 2009 working on a project where the clients inventory system ran on an AS/400 and I knew literally nothing about IBM mainframes at the time. All we wanted was them to publish a simple JSON API we could poll hourly to update the front end we were building. In a conference call with umpteen of their engineers, they basically told us that was impossible. I thought this was ridiculous, but they were insistent.
Their counter proposal was that they would automate emailing us updates and we could parse and process those. I still have no clue how that could be easier for them but it sure would have been more work and infrastructure for us!
Eventually after literally weeks of back and forth they finalized landed on letting us use FTP to read hundreds of XML files they would generate nightly. They were often mildly malformed/improperly encoded. It was simpler to deal with that than ask them to fix it. It was not a very fun project, but a major learning experience looking back.
I was a young hotshot who had only recently been promoted to lead developer, and having to interact with these people who clearly thought I was dumb for not knowing anything about IBM mainframes certainly knocked me down a peg. Kind of humbling to see you don't know what you don't know once in a while.
> the clients inventory system ran on an AS/400 and I knew literally nothing about IBM mainframes
I'm going to be "that guy": The AS/400 (nowadays System i) is not a mainframe but the last standing member of the family of midrange (outside of IBM called minicomputer) systems. (NonStop and OpenVMS - and probably something else I don't know about - are still somewhat around, but nowadays they run on more or less microcomputer systems).
It's just IBM i now. I believe it was (not including System/38) AS/400-AS/400e->eServer iSeries->eServer i5->System i5->System i->i.
Nonstop has run on X86 systems for about 10 years now, but I don't think they were ever considered 'mid-range'. I think they usually were referred to as mainframes, although the hardware architecture was totally different.
I personally thought the AS/400 was midrange. That's how a co-worker characterized it when he left us to work on OS/400 development (way back in the 1980s).
IBM's own "History of AS/400" web page sort of implies it's midrange:
"For the first time, small businesses, city governments and other medium-size enterprises could set up their own computer networks and connect them to workstations, printers, file servers and even other networks — all running four times faster than what was previously possible."
Maybe System i is more mainframe-y than the original AS/400.
The question got me looking at old AS/400 manuals on bitsavers, and there is some interesting stuff. From the AS/400 handbook:
- Layered machine architecture. This insulates users from
hardware characteristics. It enables them to move to new
hardware technology at any time, without disrupting their
application programs.
- Single-level storage. Main storage and disk storage appear
contiguous. An object is saved or restored on the system via a
device-independent addressing mechanism
- Operating System, OS/400, is a single entity, fully integrating all
the software components (relational database, communications
and networking capabilities, etc.)
I agree with you that AS/400/i has always been called mid-range. I was actually referring to NonStop as usually being called "mainframe" not mid-range, or mini-computer, at least the early pre-RISC models. It's another interesting computer architecture.
For more on the AS/400, there's a book by the lead architect of it, Frank Soltis on archive.org that goes into a lot of detail. It is really quite different from anything else.
With 128 bit pointers encoding security and providence information. And a unified memory space, no files, just addresses with RAM as a cache for persistent disks. Might as well be from 2080.
I recall in about 2009 working on a project where the clients inventory system ran on an AS/400 and I knew literally nothing about IBM mainframes at the time. All we wanted was them to publish a simple JSON API we could poll hourly to update the front end we were building. In a conference call with umpteen of their engineers, they basically told us that was impossible. I thought this was ridiculous, but they were insistent.
Their counter proposal was that they would automate emailing us updates and we could parse and process those. I still have no clue how that could be easier for them but it sure would have been more work and infrastructure for us!
Eventually after literally weeks of back and forth they finalized landed on letting us use FTP to read hundreds of XML files they would generate nightly. They were often mildly malformed/improperly encoded. It was simpler to deal with that than ask them to fix it. It was not a very fun project, but a major learning experience looking back.
I was a young hotshot who had only recently been promoted to lead developer, and having to interact with these people who clearly thought I was dumb for not knowing anything about IBM mainframes certainly knocked me down a peg. Kind of humbling to see you don't know what you don't know once in a while.