In my last post I talked about investigating AROS, the modern, open source[*] implementation of the Amiga Operating System. Today I’ve spent some more time on that study, and found some things:

  • my strategy last time was to read the AROS application developer guide in order, up to the part about Intuition (the UI toolkit). This taught me about Windows and Gadgets, and the message-passing event system IDCMP. However, one of the first things I discovered today on digging more into that is that people don’t use these things directly.
  • The AmigaOS Documentation eschews gadtools (the library for working with Intuition gadgets) in favour of BOOPSI, the Basic Object-Oriented Programming System for Intuition. Its documentation uses demos that only work on the latest (proprietary) AmigaOS, and not on earlier AmigaOS or AROS.
  • The AROS documentation eventually led me to discover that even gadgets in BOOPSI are old and busted, and that the Zune[**] widget set for BOOPSI (which is based on the freeware Magic User Interface) is the new hotness.
  • This follow-your-nose-and-end-up-lost documentation issue is a big problem. I’ve learned a lot, but mostly follow “this is how this works” with “but you don’t do this”. Plenty of reference is made to the original Amiga developer documentation (which, luckily, I have, on CD in an Amiga-only format) and the MUI docs (which I don’t have but can probably get). This is not an AROS-specific issue, wherever “open source version of X” is documented, the documentation is likely to say “check out the documentation for X”. This only works where the documentation for X is available (imagine, say, if Commodore were to go bust in 1993 and stop publishing their developer docs), and relevant to the reimplementation (imagine, say, if Apple were to change programming language and GNUstep didn’t catch up).
  • That AROS is both source and (on m68k, or on UAE) binary compatible with programs that were written in the 1980s is amazing to me, and much more valuable than having latest whizzbang features and smartwatch integration from a modern platform. Leaving aside technical aesthetics which I’m likely to disagree with a lot of people on anyway, AROS and open source[*] systems like it (Haiku, ReactOS, FreeDOS, GNUstep, Lesstif) represent a critical piece of heritage infrastructure.

[*] I’m using this as a shorthand. AROS source code is published under the terms of the AROS Public License, which is not OSI-approved. The source code is available to use, study, share and improve, which many would understand to be “open”.

[**] Unrelated to the Microsoft Zune, and it’s unclear to me which came first.


I spent the weekend teaching myself some Amiga GUI (Intuition) programming using AROS via the Icaros Desktop distribution, their developer guides, and the Amiga developer CD. It’s a nice enough system to program in that works like most other GUI systems; GUI events are sent to your process as messages that you receive, handle, and reply to. GUIs are built out of gadgets attached to windows displayed on screens.

As a system to use, it feels efficient and fast. AROS is, as the Rhapsody developer releases were, a platform displaced in time: someone designed it to run on a 680×0 with a couple of megabytes of RAM and a floppy drive, and here we are with our modern CPU, gigabytes of RAM and solid state storage. It starts near-instantly, responds quickly (even though it’s running in VirtualBox under a Windows 10 host), it’s beautiful. And it’s not overloaded with widgets and gewgaws added by vendors who are keeping up with the Joneses by adding every new feature to every platform they support. No notifications ask me whether I’m interested in a tour of all the latest features that I’d be unable to find myself.

As I write this post (in the Odyssey Web Browser in Icaros Desktop, of course), I wonder whether I need all of the other things I would get if I were doing this directly in Windows, or in macOS, or a modern Linux distribution. Give me a compiler long enough and a place to save and I shall move the Earth.