Sendiri logo


This website is currently doing service as a repository of software that I have written, and documentation thereof. Some of it is commercial, much is available as free downloads. All of it, at present, is designed to run on RISC OS, a little known but much loved British computing platform supported by the following companies:

RISC OS Developments
CJE Micros


10 Sep 2022 - Geminus RPCEmu and Geminus Any Pi

Geminus builds are now available for the RiscPC/RPCEmu and all of the Raspberry Pi devices. Find them in the store.

Geminus for RPCEmu comes with an open source extension to the RPCEmu code which offers accelerated graphics operations using native code, massively improving the speed and feel of the desktop.

Geminus is currently licensed to the Individual, meaning that it may be used on up to four devices owned by that person. Since many RISC OS users have multiple Pi devices, and Geminus Any Pi runs across the entire range of Pi devices from the first Raspberry Pi (BCM2835 with ARM11 CPU) right through to the super fast Raspberry Pi 4 (4te2, FOURtress any others...), a single licence for Geminus Any Pi will cover many users for all of their Pi(e?)s.

21 Aug 2022 - Sendiri Store opens

Hello all! Sendiri is happy to report that its store is now open.

This is the new home of all Sendiri software products, both free and commercial, and you may find it at:

Currently available are the first releases of Geminus graphics acceleration layer for the ARMbook and the i.MX6 targets:

Very shortly we hope to be completing final testing of Geminus on the Raspberry Pi 4 and RiscPC targets and adding these to the store too.

About Geminus

Geminus offers a much faster, smoother desktop experience by accelerating graphics operations and remembering window contents so they can be redrawn much more quickly when you scroll windows or move them around.

It also offers faster on-the-fly JPEG decoding and rendering which will be extremely useful to anyone working with digital photographs.

Unique to Geminus also, is the ability to rotate and transform JPEG images.

Geminus will be familiar to many (former) IYONIX pc users but on modern machines where there is much more memory available to use for window cacheing, it really shines.

On the i.MX6 targets it exploits the GPU hardware for window movement, redrawing and scrolling, using it much more extensively than all earlier software. On the ARMbook the NEON multimedia coprocessor steps in to performance this work.

For more information visit the store and download a copy under a free Demonstration licence.

All Sendiri software is available under a time- or feature-limited Demo licence allowing you to evaluate it before you commit to a purchase. Purchasing a Full licence allows you to use the software in perpetuity, and entitles you to free updates to fix any issues that are discovered in future.

In time, we intend to offer more licensing options, but currently software is licensed to the Individual and permits simultaneous installation and use on up to four suitable machines all owned by the individual user.

Aemulor Updates

Also on the store you will find an updated version of Aemulor for all targets. Aemulor remains a Free product and will run unlicensed with all of its previously-released functionality. In future, some planned features may be released commercially to provide additional functionality or accelerated performance.

Version 2.54 addresses a couple of outstanding issues relating to the handling of 26-bit C programs such as Eureka which sometimes caused issues when Aemulor was stopped. Along with these fixes, some additional work has been done to increase isolation between the 26- and 32-bit worlds to avoid such problems in future as RISC OS is further developed.


Well, we all know what happened next... shows are to be resuming soon

RISC OS Wakefield Show 2020

Later this year, Wakefield plays host to its 25th anniversary RISC OS show... Hopefully.


Register your interest in beta testing any/all of the following products:

Join the Sendiri Beta mailing list.

RISC OS South West Show 2020

See us, along with Evince, updates to Geminus, and perhaps a couple of other goodies at the RISC OS South West Show on the 22nd February.

RISC OS SouthWest Show 2020

My commercially-released software

Below are those programs which I've written and decided are reliable and useful enough to release for others. Some versions have now been released for free, for the benefit of the RISC OS community, but I continue to support and update these programs.

Aemulor - The 26-bit emulator for 32-bit RISC OS machines

Aemulor user guide

Aemulor is the software emulator that allows RISC OS applications which were written for a 26-bit ARM system to be used on more recent CPUs that provide only 32-bit addressing modes. It was originally developed for the XScale-based IYONIX pc, which uses the XScale IOP321.

By exploiting some hardware features that are new in the XScale core and not found on any earlier ARM CPU, and by careful coding to avoid unnecessary CPU load, Aemulor achieves roughly 1/3 native performance.

Since most instructions operate identically in 26- and 32-bit addressing modes, Aemulor achieves its performance by quickly ascertaining which of the application's instructions must be emulated, leaving the rest to execute natively on the XScale CPU. A number of clever tricks and some carefully-tuned code, combined with the fact that any work which the application requests of the underlying OS executes natively, allows Aemulor to achieve much greater performance than anybody ever anticipated.

Aemulor is now available for free download for all current RISC OS machines, with rolling updates to accommodate OS compatibility changes etc and to fix any issues that are discovered.

Download the appropriate version of Aemulor for your machine.

There are some additional resources relating to Aemulor available via the following links:

Aemulor user manual

Technical articles on Aemulor and Aemulor Pro, originally written for Foundation RISC User magazine.

Technical explanation of the operation of Aemulor.
Introduction to Aemulor Pro.

Evince - VNC Suite for RISC OS

Evince is an in-progress development effort to bring a modern, multi-headed VNC client implementation to all RISC OS machines

First demonstrated a the RISC OS London Show in October 2019, Evince currently allows a single RISC OS machine to be used to view and control multiple different machines on the local network, whether they are RISC OS targets, Windows servers, Linux machines or macOS. In this current guise of a multi-headed VNC client, allowing the transparent use of multiple servers, it offers display sharing, keyboard/mouse input, clipboard support, and automatic detection and authentication.

Over time, it is intended that Evince will involve to offer even more transparent operation, including integration of audio input/output, sharing of filing systems and remote adminstration/deployment/testing of software. You can find out more about the development of Evince here.

Geminus - Graphics enhancement software for RISC OS

Geminus main page

Geminus brings multi-monitor support, screen rotation (for LCD panels that can be used in portrait modes), graphics acceleration and faster JPEG rendering to the IYONIX pc desktop.

Other features include the ability to transform/rotate JPEGs, which is available for all RISC OS machines, and Red/Blue colour swapping to support other graphics cards and digital outputs such as DVI (not yet supported by the NVidia driver module).

Future features planned for inclusion in Geminus are low-bpp screen modes for legacy software (currently implemented in Aemulor Pro) and possibly support for remote screens so that you can you extend your desktop over screens connected to other computers, rather than purchasing additional hardware.

Geminus was originally published by Neil Spellings but is now available for the IYONIX pc free here.

Work is under way to bring the features and performance of Geminus to newer RISC OS machines.

Cino - Software DVD player for RISC OS

Cino download

Cino is an ambitious project to bring DVD support, including full playback of Video DVDs to the RISC OS platform for the first time ever.

The latest code is twice as fast as any other MPEG-2 decoder on the same hardware; it achieves half the required performance even on the memory bandwidth constrained XScale IOP321 of the IYONIX pc, ie. sustained 12.5fps video playback with audio decoding too. It is thus watchable but not acceptable on 2002 hardware.

On any 1GHz+ ARM CPU including Cortex-A8/9 parts, the code achieves full-rate playback without issue. (This includes BeagleBoard, PandaBoard, Raspberry Pi 2-4 and Freescale i.MX6 platforms, even using just the single CPU core supported by RISC OS on those platforms.

RISC OS and the Raspberry Pi

RISC OS has gained more attention in the popular press of late, following the creation of the Raspberry Pi family of single-board computers.

Following my initial port of RISC OS to the Pi in October 2011, whilst I was working at Broadcom, it is now in the hands of RISC OS Open for whom I occasionally do some other development work.

Free Software and Other Developments

Some free software and other development work related to the RISC OS platform.


Some of my favourite photographs among those I have taken may be found here.

Search this site:

Copyright © Sendiri 2003-2022