RISC World

Letters Page

As I sure, you will agree, we start this page with poetry...

We've been inundated with more than one letter for this issue, which is excellent news as it means that some RISC OS users are reading the magazine. Ot also means that because there's plenty of reader's input, this introduction can be quite short.

Hi Aaron,
As you might be aware, one of the things that stopped working with RISC OS 6 was the software for driving the RiscPC PC Card, !PC. Now, Aleph One made !PC open source a couple of years ago. I downloaded the source and over the last few months have been trying to figure out what was wrong. I am pleased to say that I now have a version of !PC that work with RISC OS 6. There were four issues with RISC OS 6 that I had to program around. They were not bugs in !PC but incompatibilities brought about by changes in RISC OS 6.
I have tested !PC with DR DOS, Windows 3.1 and Windows 95. I have also checked it with RISC OS 4.39 and my changes do not appear to have broken anything there. Overall, it seems to run reliably now on my RiscPC.
A couple of other people have tried it as well and had no problems with it so far.
My question is, would you be interested in putting a copy of it on a Foundation RISCWorld CD? There are probably not that many people still using the PC Card but I find it does come in useful sometimes, especially for old DOS software.
Could you let me know if you would be interested?
Dave Daniels

Many thanks for taking the time to sort out the PC card software so that it's compatible with RISC OS 6. Whilst you are right, there aren't that many people still using the PC card, it can prove to be very useful in certain circumstances and I can imagine that for a small subset of users not having access to DOs or Windows 95 after installing RISC OS 6 could be rather annoying.

I have placed a copy in the letters directory (inside Software) on this issue. At Dave's suggestion I have also spoken to RISCOS Ltd and it's intended to include the new version of !PC with the next RISC OS 6 CD. With rgard to !PC, it's quite interesting how old bugs can turn up in well loved applications now that RISC OS 6 has tightened up the security and stability of RISC OS, as an example a bug that has been in Impressions ABI mod since day one only showed up when the first version of RISC OS 6 was released.

Now, on the subject of things that don't quite work as expected...

Dear Aaron,
Due to a combination of an intergalactic move (OK, inter-island, from Japan's Honshuu to NZ's Te Ika a Maui (North Island) - same diff, really), and house renovations, and urgent teleworking, I totally missed the "what I like about RISC OS" contest. Being a good little boy, I wasn't going to chip in belatedly until I finally got into my FRW CD and saw Hugh Jampton's almost-joking "Automatic Updates" screenshot, and got a reminder of something that severely jangles my nerves.
I get two lots of these screens, one on the Mac I'm using, and one on the Windows XP downgrade I had to install to get Visio, which I need to have for inter-working.
On the Mac, they come in, annoy, but can be deferred until shut-down, at which point they do their stuff (actually at shut-down, so the next start-up is "clean"). Grrr - but bearable. On XP, they come in, actually START the restart process, and get deferred because I'm busy using the wretched thing and don't have time for a restart. Undeterred, some time later, up comes the same screen to say it's restarting my computer, so I defer it again - and again - and again. How rude can you get?
One of the best things about RISC OS is that whatever annoying things it might rarely do, it never does anything as crass as that.
Am I running VRPC on the Mac? Well, no, because I've still got a genuine RPC that runs RO 4.39 quite nicely, thank you (and much better than old Macs and PCs run their recent OSs, which is basically not at all).
Michael Poole

It's a shame that you missed the quiz about what people like, and indeed why they use, RISC OS. The results were quite interesting. Although the article has been published we are quite happy to print any follow up comments from readers.

With regard to the Windows automatic update process, it amazes me the number of times I see people complaining that Windows has installed some updates and wants to restart whilst the user is still working on the machine. If this behavour gets up your nose, and it quite rightly should, then simply alter the way Windows handles automatic updates. All of my machines are set to download updates automatically, but to only install them when I say so. This is typically when I shut down the machine at the end of the day. The following screenshot from the Automatic Updates option window in Windows XP shows what I mean:


As you can see the Download updates for me, but let me choose when to install them. button is ticked. It's worth remembering that if a particular feature of Windows doesn't appeal, or indeed gets in the way, then there is quite likely to be an option to change the behaviour somewhere. My final comment with regard to automatic updates is this. Whilst they may seem to be a pain, there are regularly people moaning that "making sure Windows is up tp date takes ages", with the correct settings updates take no time at all for the user. Windows does the lot. Of course RISC OS doesn't have this problem. Not because it's better designed, but because there aren't regular free updates to fix problems.

Now let's hand over to a Foundation RISCWorld letters page regular...

Dear Aaron,
I thought up a new project, that to do some calculations with matrices. Given matrix A and vector y, finds vector x, such that A.x=y. In the process, finds the determinant of A, finds its 'characteristic equation' and solves that equation, giving the eigenvalues.
To do this, I had to find out how to solve quadratic, cubic and quartic polynomial equations. I only went up to a 4 x 4 matrix, because the quintic is generally insoluble. i.e. There is no direct algebraic method of calculating its roots. (As demonstrated in about the 1700's by a mathematician called 'Galois', the night before he was killed in a duel:-( There are ways you can numerically find the eigenvalues of any matrix, but I don't have the info to hand.
Please find attached, zipped, !Matrix, that does the job.
No doubt, I'll find some bug or other, but no matter!
Martin Carradus.

Thanks for sending a copy of this and I will of course be including it on this CD. I'm not really in a position to comment about the math involved with working out the vectors of a matrix, this is mainly because I was asleep for the 6 months when we covered this subject at school. As a result my skills just about extend to working out that 2+2 spells Cat. However I am familiar with Galois, having smoked some of his cigarettes on a trip to france.

As I was starting work on this issue, just after the previous issue was duplicated and sent to subscribers I got a follow up e-mail from Martin...

Hi Aaron,
Thanks very much for including my application !QuineMcC on the last subscription CD, albeit a bit academic.
I was unhappy with the representation of the coefficients of characteristic equation by !Matrix Version 2.00. It only showed them by up to two decimal places, which meant there was underflow with small values. In the process of looking into this, I discovered that, with the 4x4 matrix, !Matrix was entirely miscalculating the characteristic equation, and consequently the eigenvalues. I have now corrected that.
Attached, please find !Matrix, Version 3.00. I have tested it out, to some extent, and it all seems O.K., now.

The copy of Foundation RISCWorld must have arrived whilst we were having our e-mail conversation. I was delighted to include !QuineMcC on the last issue. I am also please to include !Matrix on this issue. I had already included version 2.0, from your earlier e-mail, but have updated this to version 3.0 following your changes. A copy is in the Letters directory inside the Software directory on this very issue.

To contact the RISCWorld letters page please e-mail us using the following e-mail address. The deadline for letters being published in the next issue is the 10th of January.

Aaron Timbrell