Rick's b.log - entry 2022/11/01

Ghosts

But wouldn't it be cool if ghosts were real?

Or maybe not, if you think of what a ghost is supposed to be. An earthbound spirit that never made it anywhere else. Usually due to "unfinished business".

I would not be the person to panic and run at the sight of a ghost. No, I'd be that annoying git that asks question like "How can you exist?" and "What are you made of?" whilst gently tossing Maltesters at it to see if they bounce off or pass right through.
(of course, in a horror movie setting that means I'm either the one that's too cuckoo to die, or the second to die (black guy dies first, it's a trope...))

Now, you'd think I'd believe in ghosts, given that I believe that people are spirits temporarily inhabiting a biological shell, which pretty much provides a framework upon to which to hang the bedsheet.
However the question is not whether or not a spirit can exist separately to the body, but rather, can it manifest by itself independently of a body?
And there we hit the problem. What does a spirit look like?
We tend to imagine that ghosts look more or less "like people", either type of whitish apparition (leading to the whole bedsheet thing) or actually like people only sort of faded and partially translucent, like an old photograph.

Why? Because this is the form that we are most liable to recognise and accept? It's the same thing as why we "imagine" aliens to be vaguely humanoid shape, even though nature provides plenty of examples of creatures that don't follow the head-torso-two-arms-two-legs pattern.
Granted, the layout is quite common on this planet, most mammals are of a similar pattern even if the details differ. One could even argue that the diplodocus is a sort of weird giraffe, even though they share nothing in common and evolved in different times and in different ways.
Except, that's not actually entirely correct. The jump from water dwelling creatures to land based creatures was the Tiktaalik, and one can see a prototype version of this base body shape there (it's not unlike a sort of crocodile in shape), so there is an ancestor common to all mammals, from dinosaurs to us.

With this in mind, it's perfectly possible to find a water world inhabited by sentient octupi who swim amongst jellyfish and starfish, and nothing on that planet has four legs. What's the point of legs on a water world?

Which brings us back to the original point. Why do we assume that a ghost would look like a person? Even restricting ourselves to earthbound life, why not a ghost goldfish?
So assuming a spirit were to somehow manifest in a visible form (which itself opens up so many questions about the origin of the energy that would make that possible), it's rather ridiculous to expect this spirit to look not only humanoid, but a recognisable person. Wearing faded period-appropriate clothes, for deity's sake... Bonus facepalm points if it is sepia toned.

Hmmm, perhaps that peculiarity that we currently refer to as "dark matter" is actually spirits moving from one body to the next, and the universe is simply life churning?

Something I personally find interesting is that the Arabs were the earliest scientists, and a lot of the things they discovered and named (like most of the stars...) are still relevant to us today.
Yet, today, it is hard to think of Arabs without Islam being a part of that. Why did they seemingly turn their back on the science and embrace a belief system that endorses acts of violence?
Oh, and don't think I'm bashing Islam here. Christianity can't take any moral ground whatsoever. The Dark Ages was suppressing and hiding scientific discoveries of the past in order to promote the whole God hoodoo, and Christians certainly went and conquered and colonised with the best of them. And when they ran out of people to oppress or simply kill, they screamed "WITCHES!" and turned on their own.
And as the whole abortion situation in the United States shows, plus ça change...

Maybe, just maybe, the Arabs all those thousands of years ago, worked it out. Understood the churn. And went mad from the revelation.

For me, knowing the universe is full of life would be absolutely beyond awesome. Knowing that when I croak it, I'll end up in another body in another place... it seems much more useful than the idea of born - lived - died - the end; which is, let's face it, utterly fucking pointless when you think about it.

I don't need to be told I'm special or loved by some beardy bloke in the clouds. I am happy to be a tiny insignificant part of something that might be mundane on a universal scale but would be astonishing on a human scale.
Sadly, there are many many people who would have a complete breakdown over this. They'd lose it completely and, through their actions, would certainly contribute to the churn. Because they have been fed a lifelong narrative of them being special. God's children, the chosen, whatever words are selected it's basically the same narrative - the smug "I'm better than you because...".

Me? Push me into the churn. I'll end up as a sort of vaguely spider-looking creature on a forest planet somewhere beyond Achernar.
And the only thing I'd regret? Not having eyes to see the galaxies and nebulae on the journey over.

Honouring the dead

Actually, let's back up there. I exist because of her. She married a drunk Glaswegian twat and somehow magically I turned up, a sober Glaswegian twat.

Knowing that mom was big on ecology, and thus didn't want a fancy marble grave thingy, she spent a couple of years as a small heap of gravel. The commune didn't feel that was quite right, so somebody (I don't know who) put together a wooden surround to demarcate the grave.
Simple, biodegradable, and not at all flashy. I think mom would have approved.

Here lies the gooey bits...

The flower on the right is a crysanthenum. This is the flower associated with graves in France (so - protip, never take one to cheer up a person in hospital!). The pink one centre-right, I think, is a sort of heather. Also a graveyard fixture.
The two plants on the left are plastic. They stay there all the time. The rose stuck between them and the big daisy on the far left are the sole survivors of previous plastic plants. The rose lying down is one that I was given at work for "Octobre rose", or a campaign for breast cancer awareness.

Now the flowers above the laminated paper saying who's there.

A little bouquet.

The pink rose is the one by the driveway that mom always stopped to smell. The yellow one is the little rose that I rescued from a certain death in the Noz in Craon the last time mom and I went there. Two sprigs of the huge weeping willow, as it is associated with dreaming, intuition, and femininity. And, finally, a sprig of oak for strength, as it's one of the most sacred of trees. There's also a tiny bit of Thyme lurking behind the yellow rose, for protection and positivity.

Afterwards, I came home and set up the halogen cooker to bake some potatoes (that I had with grated cheddar). As that was cooking, I listened to Tristania's World of Glass album (from YouTube), turned the potatoes over, then listened to the Beyond the Veil album.
Along the way, I made myself a cheesecake. Nothing special, it's a Green's whisk-and-serve style. But, about my level of culinary competence. ☺

Chasing ghosts

So I did that, and one day I sat down to have a play of Mamie Fletcher's House only to be greeted with...

Not good.

Wait, what?

I have set my Pi 2 up to use GPU rescaling, that's to say the disable_mode_changes thing in the configuration. The mode definitions available has a 1280×720 (HD) mode that Mamie requires, and the GPU will handle fitting that to the 1024×600 size of the display. It's basically 16:9 just with fewer pixels than HD.

It should work. But... wasn't.

I do some freaky finagling to get the whizz-in effect working, so I was wondering if somehow this was overwriting memory and causing a crash. The location of the last part of the backtrace is at +&105A8 within SharedCLibrary.

So I disabled the whizzer code.
It still crashed.

Okay, I hardwired to drop directly into a game.
It worked.

To the menu instead with no effects?
Crash.

I hacked out all of the screen buffering stuff, so it just draw everything directly to the screen.
Crash.

Okay, time to look a little closer at the dump.

Point of crash:
20352044 : .0.á : E1B03083 : MOVS    a4,a4,LSL #1
20352048 : ..A  : 20411080 : SUBCS   a2,a2,a1,LSL #1
2035204C : ...ä : E4910002 : LDR     a1,[a2],#2
20352050 : .à_â : E28CC001 : ADD     ip,ip,#1
20352054 < ...à : E000082E : AND     a1,a1,lr,LSR #16
20352058 : ..Pâ : E2500C02 : SUBS    a1,a1,#&0200       ; =512

Something on this machine is setting the Debugger options to APCS, which is why the a2, a4 style registers. It's annoying, but I don't look at assembler enough to want to figure out what is doing this.

Anyway, crappy APCS style registers aside, something stands out like a sore thumb. You see, the faulty instruction is two instructions before the current location of the program counter (indicated by the <).
Which means it is the LDR a1,[a2],#2 faulting.

Wait, what?

I didn't even need to look at the values of the registers to smell a rat. It was that #2 at the end. Something is dealing with rotated halfwords, the following code shifting by sixteen pretty much confirmed it. This is old style ARM behaviour. Then I remembered, the Pi 1 had a processor flag to choose between the old rotated loads behaviour, or a proper unaligned load.

If that reads like gibberish to you, just know that the original ARM processors could only load data from a word aligned location (that is, an address divisible by four). If you tried to load from an address not divisible by four, you'd get some weird stuff happening, like it would load the data but in the wrong order.
This would often be used as a quick way of loading subsequent 16 bit values, such as audio samples. Simply load it in and push it into the right place using a rotate instruction.

My computers are all set to generate alignment exceptions. That means if there is any attempt to load from an address not divisible by four, the processor will fault it. There is very little code that actually uses proper unaligned loads (as available on ARMv6 and later). Iris does and...? I think that's about it?

Anyway, this was crashing Mamie. But why? It's built using a recent (if not the most recent, have to check which one is on this machine) version of the Norcroft/Acorn compiler, and SharedCLibrary won't be bugged in that way as it is built into ROM and it's a ROM build from early September.

So logically we can rule out Mamie being faulty.
But still it is crashing.

So let's ignore the backtrace, as this only shows the state of the world as far as Mamie is concerned. If we look more carefully, something I should have done had I had more tea in me, it would have stood out better that the backtrace says:

PC = &FC18E724 : Function  (at &FC18E6C8)

2035204C : ...ä : E4910002 : LDR     a1,[a2],#2

So, you dozy twat Rick, it's borking at something in the RMA (a 20xxxxxx address) rather than the system ROM (an Fxxxxxxx address).

*Where 203807AC
Address &203807AC is at offset &00000B18 in module 'AMPlayer'

And there we have it. It was actually AMPlayer crashing, but the RISC OS error handling is kind of messed up, so the problem was percolating up until it hit something capable of responding to the error condition, which was Mamie. Which promptly fell over due to seeing the exception and thinking that something bad had gone wrong. It had, but with something else.

Why was AMPlayer borking? Because, remember, I copied a lot of stuff over from the Pi 1's SD card. Which means, it's probably a really old build of AMPlayer... it's 1.39 from 2002. So it would have been 32 bit aimed at the Iyonix, and working on the original Pi because it also could do the rotated loads stuff.
I picked up a later version, 1.42 from 2017, and installed it.

Now Mamie works. ☺

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Gavin Wraith, 1st November 2022, 23:03

Those whirling dust-devils that you can see in deserts - easy to see why people thought that they were stirred up by something invisible passing through. They are djinns. Can Arabic speakers please confirm that that word can also mean "a fart"?     I have never seen a ghost, but I did once experience something rather creepy. It was among the rhododendron bushes in the park of some student lodgings of Southampton University. At breakfast I told my hosts that I had taken an early morning walk and that in a certain spot I had felt decidedly ill. They replied "yes we know about that. We do not talk about it."

Rob, 2nd November 2022, 16:00

A previous house I lived in, I was sure I caught a glimpse a strange boy on the stairs - I turned back, and there was nobody there. But that exact spot would often feel decidedly cold, even when the rest of the house was warm..

C Ferris, 2nd November 2022, 19:36

There was a weird tale down here - a bloke was cleaning out a old stable and heard clip clop from a horse which was being lead in and tied up in front of him. He could feel it's warmth - the horses collar was put on a wooden peg behind the horse.  The bloke looked again the horse had gone and no collar was on the wooden peg - the bloke legged it!

David Pilling, 5th November 2022, 12:53

David Mitchell does a comedy riff on ghosts ("would I lie to you"), saying how come they are not all concentrated where lots of people have lived. More worrying are the cheap TV channels ("Really") which put on ghost programmes every night - the ones where minor celebrities go out at night and investigate a haunted house.    For Halloween, Blackpool Transport offered a tour of the old "haunted" tram sheds by night. Offering various poor customer experiences from the last 120 years as the source of the ghosts.    If you grew up with the BBC Micro you have an over simple view of computers - the punters you meet struggling with them know they are alive and have a spirit. Offer a computer exorcism service - loadsa money.

Rick, 5th November 2022, 17:48

Those Ghost programmes are dead cheap to make (here's a camera and a sound guy, go into this old house and squeal) so it's probably why they are made. Don't even need to dec up a studio.    If the computer is running Windows, I'm afraid a simple exorcism won't help. It needs banishment, in a deep hole, and the ground sealed and salted afterwards.

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