Rick's b.log - entry 2018/04/01

RISC OS for all

About seven weeks ago I won the Euro lottery. I probably should have booked myself a holiday in Japan, but instead I have been working on sorting out some of the issues regarding RISC OS.

One of those questions is the perennial issue of there being two branches of RISC OS, the closed source RISC OS 4 (also variously known as Select, Adjust, or SIX) and the open source (but not in the OSI definition) RISC OS 5.

That will soon cease to be the case. I have purchased the source to the former RISC OS Ltd versions from 3QD for an undisclosed sum. These sources have been given to RISC OS Open Ltd for picking apart and merging that which is useful into the main code base to create a unified version of RISC OS which will be known as RISC OS Unified (though we'll all still call it RISC OS 5). The code will be released under the same standard Castle licence as the majority of the Acorn era code.
The results of this will start to trickle through slowly, for while a 32 bit version of RISC OS 4 was created (for the A9home), it was done in a way rather different to how the Castle implementation went about it. Furthermore, the lack of a HAL in ROLtd's versions of RISC OS means that it is still tied fairly heavily to the specific architectures of the machines supported (each build has a hardware abstracted kernel!), plus there are the problems of finding and fixing hardware level things such as unaligned loads, ARMv7 safe, and ARMv8 safe - these issues having arisen after the work on the ROLtd versions effectively ceased. Recall that the A9home uses an ARM926EJS processor (the same as my old PVR!) which makes it an ARMv5 era processor.

One of the guarantees offered by this agreement is that Aaron Timbrell may continue supplying RISC OS (any version, but soon the Unified version) with his VirtualRiscPC emulator. He has been hard at work modifying the emulator to support RISC OS 5, and will soon be unveiling an exciting new feature called the "6 bit extension" which will permit 26 bit applications to run seamlessly on a 32 bit machine by detecting the switch into a 26 bit application or module and altering the entire emulator behaviour accordingly. In essence, the emulator will be a 26 bit machine for 26 bit code, and a 32 bit machine for 32 bit code. In addition to that, Aaron has noted that some of the older applications do not properly support a RiscPC environment, so he has taken some of the code from his older VirtualA5000 emulator to detect if a 26 bit application misbehaves, and if it does, to examine the reason for the misbehaviour by looking to see which instructions failed. Depending upon the results of that, the emulator will flag those applications to 'see' an ARM3 processor and an IOC/MEMC style machine. As the emulator is doing this, it all happens transparently and the 32 bit version of RISC OS (RISC OS Unified) won't be any the wiser. The emulator is also smart enough to trap various SWI calls and return fake information so programs that try to detect the machine type will receive the correct data for that which the emulator decides is suitable.
It is a really fascinating development, and I believe Aaron is in the process of writing an article on how it works for Archive magazine.
Aaron will make an announcement of a new version of his emulator products shortly, once final testing is complete, and he points out that we should watch for the latest benchmarks comparing the emulator on a modern PC with real machines such as the Pi and OMAP family of devices. I believe the phrase "VRPC hands the Pi3 it's ass on a silver platter" might just about cover it...moreso now it can totally seamlessly run just about any RISC OS program ever written. I mean...damn.

For those of us with real 32 bit hardware, Adrian Lees recently released Aemulor as a free product for all of the supported platforms - check here if you do not already have Aemulor for your machine. Just, don't try running !FCFS (shame!) or AcornDTP (probably just as well). I speak from experience... That said, the essentials (older versions of ArtWorks, all versions of Impression, etc) work well so nobody needs to be too worried about the perceived lack of compatibility between RISC OS 5 and the 26 bit era. For emulation, Aaron has your back, and for real silicon, Adrian has you covered. There's really no reason to stick with an ancient version of RISC OS, not when RISC OS Unified rolls out.

This is good news for the entire RISC OS community, with one small exception. Rounded buttons. Yup, that's part of the RISC OS 4 WindowManager, and maybe some people actually like it? I don't know. But don't worry, directories will be forever blue. That is not going to change. If you prefer green, load a theme...

Now I can book a holiday. I fear I have missed the cherry blossom this year as it is already out in bloom in Tokyo (yes, this early!), so I think in the near future I'll go to Italy by train. At least it ought to be warmer than this horrible never-ending winter. Then go to Germany this summer. I ought to "do Europe" first, before the Tories go and cock up everything with Brexit. :-(

Oh, and you know the strangest thing? All those digits in my bank account and I have no desire whatsoever to go out and buy a new computer. My PC is an old P4 clocking 2.8GHz and running XP in a little over a GB of RAM, however I pretty much only ever turn it on in order to update my website (WinSCP). For most stuff, I use my phone. For personal enjoyment, I use my Pi. I'm quite happy with my ARMv7 Pi2. I'm writing this right now in Zap (now that I've fixed Zap to play nice on ARMv7). I don't really see how a new computer will benefit. A new camera, on the other hand... A nice DSLR, but not one too flashy as I want to take it on holiday with me...

Sorry, I'm thinking aloud. Just basically waffling while wrestling with the really difficult questions in life, such as - should I put the kettle on or not? You know what? I think yes. It's never a bad time to have a cup pf tea.

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Dave Lawton, 1st April 2018, 12:23

Oh so well written, both you, and Vince are congratulated. <grin> Hope you enjoyed your cuppa.

VinceH, 1st April 2018, 13:03

The credit belongs entirely to Rick on this one. The RISCOSitory post was hastily written last night after he gave me the heads up.

malcolm, 1st April 2018, 16:19

Excellent work,rare to see such efforts

Gavin Wraith, 2nd April 2018, 13:13

Happy Easter indeed!

Rob, 5th April 2018, 02:43

OMG. Congrats, and well done! And such a wonderful way to spend the money!

Jim Nagel, 11th April 2018, 03:43

Please, also buy up the Acorn trademark and nut logo that is held (last time I looked) by some opportunist holding company, so that these can be reunited with the unified OS.

Rick, 13th April 2018, 22:05

For those reading today... Check the date of this article. ;-)

Dave Lawton, 14th April 2018, 12:28

I so enjoyed reading it Rick, so plausible :)  I just wish...

Richard Mellish, 19th April 2018, 14:07

When I first saw this in Archive magazine (after 1st April) I thought it must be an April Fool story, but I did begin to wonder after finally coming here today and reading the whole story above, which remains just barely plausible all the way through; though in true April Fool fashion it progessively stretches plausibility. So thank you, Rick, both for the story and for your 13th April comment.

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