All information herein is the view of the author. Use at your own risk, no warranty of any kind is provided.

RISC OS and the ARM CPU go hand in hand, with the first ever ARM Based devices of any kind being Desktop Acorn Computers running RISC OS. From RISC OS 2 through RISC OS 5.28 (and newer) RISC OS is a great Operating System. From the Acorn A3010 through the Raspberry Pi 2B (BCM2836 version) the line of computers that run RISC OS and there ARM CPU's are among the best for real usability of any from the view of us that like 32-bit ARM Computers. From the ARMv2 through the ARMv6 (and some ARMv7 versions) we have great 32-bit RISC CPUs that are fun to program for.

This site is intended to carry my creations, as well as a few articles I am attempting to write relating to RISC OS programming, as well as some relating to retro-computing, and a few on the concept of extremely long term usable computing. If you find anything useful, please take advantage, if not that is ok. The content of this site is provided AS-IS without any warranty of any kind.


BASIC V will always hold a place in my heart for obvious reasons.


Beings as I was for a time known of in the USA Amiga and Atari ST world I am often asked why I choose to use and program for RISC OS now. First it should be noted, that I have actually been involved in the USA RISC OS world since the late 1980s (when RISC OS was just getting its feet wet). Unfortunately most of the very small number of USA RISC OS users from then are no longer RISC OS users, most of them dropped out shortly after Acorn closed shop.

As far as why I continue with RISC OS instead of one of the others? Well I have always gained more enjoyment from using RISC OS as well as from coding for RISC OS than the others. There is something about RISC OS that really speaks to the simplicity that personal computers are supposed to be.

For me many things about how things are done in RISC OS seem more intuitive, more productive, and simpler to do than the equivalents in other Operating Systems. Like not having a standard file dialog in RISC OS, instead we drag and drop directly to the Filer windows (Filer in RISC OS is like Desktop in GEM, or Workbench in Amiga OS). Or the way that inter application transfer is often done with Drag and Drop.

Then there is the very intuitive API for most things, direct SWI calls to do most of what the OS offers. It is a simple enough API to understand completely, while being rich enough to provide everything that applications require.

Click for more about what RISC OS is to me.

About me:
This section is to fill the expected obligation of personal information.

My name is David Cagle. In the past I have been known as Zerro, Zerro-Bellow and DavidS, always with the spelling of Zerro having a doubled 'rr' as a nod to my youth. I have used and coded on computers starting in the early 1980s while I was still a kid, and became addicted to the ARM and RISC OS in the late 1980s (starting heavily in 1988).

There is some software from my past still floating around. I have been unseen online outside the ARM world since 2000 until about 2018. This began do to disagreeing with the misuse of the internet (which disagreement continues), though was prolonged by becoming paralysed in 2008 and then having a stroke in 2016. I did become involved in a few ARM, RISC OS, and P8X32A related forums during the time I was otherwise away.

In brief my programming chronology is:

  • Started with MS-BASIC on the Commodore 8-bit 6502 machines.
  • Got into Amiga and Atari 16/32-bit systems in 1985/6.
  • Amiga BASIC starting in 1985.

  • M680x0 Assembly Language beginning in 1986.
  • Started studying 8-bit 6502 Assembly in 1987.
  • First RISC CPU system in 1988 (ARM based Archimedes A3010).
  • Got to know BBC BASIC V on the Archimedes well.
  • Learned and began to love ARM assembly Language on the Archimedes
  • Upgraded to RISC OS in 1989.
  • Began Computer Sciences studies at University in 1990. Learned to love Pascal at university.
  • A little more Amiga stuff, some Apple Macintosh, some IIgs, and a little PC stuff got mixed in in the 1990s, also learned the antique known as Unix (and gained great thanks for it being a relic of the past).
  • RiscPC in mid 1990's.
  • Started playing with the 26 year old (at the time, now 52 year old) toy called C in 1996.
  • Stuck with RISC OS almost exclusively, with a little Amiga mixed in for enjoyment, and an occasional Macintosh System Software when absolutely needed.
  • Since 2004 I have tried to give Linux, BSD, and MINIX a fair shake, they are still too much the antique, outdated, time sharing system of Unix.
  • Was strong on Amiga for a while after Acorn fell. Still used RISC OS on the RiscPC though used Amiga a bit more do to available HW.
  • in 2012 the release of the RPi brought me back to RISC OS, Pascal, BBC BASIC V, and ARM Assembly Language in full force, I am still here in 2022.

The above list is just a quick overview. I may one day dig up as much of my old software as possible and post a history of what I produced, though only so it can be used. I could care less if others knew of the human behind the software, my creations are important if someone else wishes to use them (I enjoy the piece of being an intorvert). I am a bit of a perfectionist, thus making me slow to release new works, especially since my stroke, sorry. I am very happy and content with my life of meditation, and creation.


© David Cagle
This site created on RISC OS using !Zap.
Hosting for this site provided by David F
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Page Updated in August 2022.