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Comment by markus_zhang | Hacker News Reader

Is it possible to make a gui game?

It has always been predominantly a text-oriented platform but there has been some graphics support over the years.

IBM ported their mainframe graphics package GDDM to the AS/400. I don’t think many people used it but it could be used for drawing charts. It required a special version of the physical 5250 terminal with graphics support. Standard 5250 terminal emulators don’t support the graphics extensions; IBM had a 5250 emulator with graphics support for MS-DOS; apparently they never ported it to Windows or anything else.

GDDM saw more use on IBM mainframes. On mainframes it has 3D graphics support with PHIGS as the API. Several late 70s / early 80s high-end CAD systems (such as CADAM and CATIA) used GDDM, before moving off the mainframe on to Unix (and later, Windows and Linux). Don’t think the 3D part was ever ported to OS/400 though, I think GDDM/400 is 2D only.

At one point (years ago) IBM was pushing a technology called RAWT (Remote AWT) which is basically Java AWT over RMI. I don’t think it is supported any more but older versions of the 400/i JVM included the RAWT JAR.

400/i also ships with a (deprecated) Java/XML based GUI framework called Graphical Toolkit - however, it is actually intended to run on client machines (primarily Windows), not the host.

The AIX compatibility environment (PASE) includes X11 ported from AIX (and more recently IBM has made X.org X11 available as well, which is more modern than AIX X11). I believe the only local X server supported though is Xvnc; the operating system doesn’t support graphics cards.

AFAIK it can only do text games, but I don't know what improvements IBM has made in two decades. The other limitation is that the terminal buffers input until you press Enter, then sends the entire screen, so only turn-based games are practical.

The buffering is a neat feature. Your AS/400 could be extremely busy (sometimes the operator would prioritize a very urgent process), but you could do a screenful of code, then press Enter and go for a coffee.

This is why graybeards understand the difference between the [RETURN] key and the [ENTER] key.

Accountants, too.

I believe the AS/400 calls it Field Exit. One of the things I used to do for new users was remap Field Exist to Enter in the IBM 5250 emulation software. Then the enter key acted like the user expected (on a real 5250 terminal there is a separate physical Enter key located where the right control key is on modern keyboards).

Explaining Field Exit vs Enter was something most users didn't get. However, they did understand Enter as like a submit button (like on web pages) and were fine selecting fields with the mouse.

It's been many years, but wasn't that a key that allowed you to change input fields, just like TAB does it with web pages? IIRC that key was managed purely client-side.

It is my understanding there is a third party port of X to the machine. I would guess you would have to do X11 forwarding, but theoretically it could work.

Nowadays IBM supplies X11 as part of PASE - AIX X11 is included and IBM offers X.org for install using yum. But the OS doesn’t support graphics cards so X11 is either using Xvnc or X11 forwarding.

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