The last version of RISC OS to be released by Acorn was version 4. At the time of writing, two companies each develop their own fork of RISCOS 4. RISCOS 5 is the version that Castle Technology has developed to power their own Iyonix workstation (see below). RISCOS Select is the version of RO4 being developed by RISCOS Ltd. Select runs on legacy hardware and on the currently manufactured A9 range of workstations (also see below).
This split has been the cause of much heated debate within the community. Some users argue that duplication of effort is the result of two companies developing independent forks of the OS.
From a developer perspective, it is possible release software that can run on either branch of the fork. The problems begin if they want to release something that takes advantage of the additional features of either branch. For example, if the program were directly connected with USB functionality, it would have to address the two incompatible USB stacks separately. This means extra work for the developer.
I'm going to present a more neutral, if slightly controversial, position on this point: I don't see what harm having two companies developing RISC OS has actually done so far. Certainly, both companies had to develop features such as the USB stack. If both companies merged, there would be less duplication of effort in areas such as this. But what solutions are there? Would a unified company developing a unified version of the OS make exactly twice as much money? That is what would be needed if this new unified company were to employ all of the same people from both of the old companies.
Both companies are interested in developing the potential for RISCOS to make gains within niche and embedded markets in addition to desktop success. For example, Advantage 6 make a version of their rugged A9 machine (see below) which runs a specially tailored RISCOS Select, is designed to wall-mounted and comes complete with GPS*. In a sense, RISCOS Ltd. and Castle Technology are direct competitors. But in another, they are 'running mates', both attempting to advance the acceptance of RISCOS within diverse markets. They are both offering RISCOS based products and services and it doesn't make much business sense for either company to stop making these products or to merge with the other.
In a way, RISCOS development into these niche markets makes more sense than do attempts to make RO into a Windows-beater in the commercial market. This is a point that I will develop further in the final section of this article.
* Ah, the latest RISCOS development: 'the wall-mounted GPS'. Always makes me smile to read that. Before, you ask, it's for use on board ships etc ;-)
What It Takes To Run RISCOS
There are two different ways of running RISCOS as your desktop OS - through emulation or by running on native hardware.
The Hardware Option
The native hardware option contains, within it, two further options: to run RISCOS on old, legacy hardware or to buy one of the workstations which are currently being manufactured and sold.
The legacy hardware is very old now. The highest spec 'Acorn' branded workstation to be released was the 'RISC PC'.
Summary of RISC PC on wikipedia - http://en.wikipedia.org/wiki/Riscpc
Upgraded to its maximum specification, an official production machine supports a 233MHz ARM processor. Unfortunately, in this configuration, the processor is hosted upon a motherboard which runs upon a 16MHz front side bus. Another strike against machines of this type and vintage, is that the ARM chips that they support do not implement hardware floating point. Hardware floating point comes into its own with calculation-heavy tasks such as movie and audio playback and encoding and real-time 3D graphics. Making matters worse, the RISC PC class of machine doesn't include much in the way of graphics acceleration; there is no bit blit acceleration for example.
Third party upgrades have attempted to side-step some of these issues by offering local memory on the processor card and the possibility of adding a standard AGP graphics card, via an adaptor. These upgrades alleviate some of the problems of the platform but they can't push it to the standards of sheer calculative and media manipulation horsepower that current-technology workstations enjoy.
Many of the applications and the OS itself work remarkably well on the old hardware. However, the machine is incapable of, within currently acceptable standards of performance, running a full-featured web browser, running modern 3d games or playing back full res video.
There are, I'm sure, people still performing a task such as 'writing a letter' on a C64 with add-on 5.25inch floppy disk drive and dot-matrix printer. However, I'm not willing to use a C64 as my main workstation for these tasks even though it might, technically be possible. For the the same reason and for the purposes of this overview, I'm not going to pay much attention to these older workstations.