Category: Sci/Tech

The “Mr Redox” Home Energy Reactor (by )

So, I work from home, which means I spend a lot of time in my workshop.

It's a long, thin, building. The door opens into the metalworking area; moving along the building, we get to the electronics bench, then to my desk. As I've previously mentioned, I want to redesign the place a bit, but I'll still be spending a lot of time in here. I have insulated the roof successfully, but the second front in my war against chilliness is my rocket mass heater.

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It’s time for Bitcoin to die (by )

In my original writings about Bitcoin ( 2011: Bitcoin Security 2013: The Ups and Downs of Bitconi Bitcoin Pseudoonymity The True Value of a Bitcoin On the Unfair Distribution of Capital Bitcoin and Banks Bitcoin: Better than a Euro Bank?), I was pretty positive about the whole thing, but since then I've changed my mind for three reasons:

  1. The Bitcoin community has become dominated by price speculation/investment, obsessing about its current price, rather than about actually doing Internet money properly.
  2. Perhaps because the price has surged so rapidly, it's become very profitable for miners to compete for the mining bounties, leading to enormous amounts of mining hardware being manufactured and consuming enormous amounts of power.
  3. The Bitcoin protocol has struggled to scale to handle high transaction volumes, in part due to it being a difficult technical problem and in part due to politics with various groups fighting over the correct solution (a fight which, to some extent, is fuelled by the vested interests of investors and miners wanting to keep the status quo), leading to transaction fees being unreasonably high as people compete to get their transactions processed.

In the early days, an increasing number of online shops accepted bitcoin; but many have now stopped, and new ones don't seem to be being added any more. Bitcoin's bid to become Proper Internet Money has, sadly, failed. Perhaps the mining energy issue could have been avoided with a different hashing function that's less amenable to economies of scale, or if the mining rewards had been set lower so that mining wasn't so profitable (or would reducing the supply just push prices up further?)... The scaling issues leading to high fees, and the slow transactions, have meant that Bitcoin remains clunky compared to card payments, so it never took off very well as a way of paying for stuff, meaning that its value focussed more and more on being an investment and a way for transferring large sums. Ironically, it did become "digital gold", but not in a good way.

But Bitcoin isn't the only fish in the sea... Discounting all the I-made-my-own-blockchain clones with no real technological differences, there are a few interesting other cryptocurrencies that have arisen.

First worth mentioning would be Ethereum, which extends Bitcoin's transaction processing model to a much more generic distributed computation model, leading to all sorts of interesting (and sometimes hilarious or horrible) things. However, my main conclusion from watching all this is that human software development practices aren't mature enough to write autonomous financial algorithms yet, so Ethereum is, in my mind, an interesting experiment but not practically useful for anything yet. And it's also proof-of-work based, so has the same problem with miners consuming power, and has people speculating on it as an investment, and so on.

But far more interesting to me right now is Nano, which aims squarely at Bitcoin's original goal - being Internet money. The distributed consensus algorithm doesn't involve mining blocks, so is fast and there aren't transaction fees, and there aren't any miners burning CPU cycles to try and win money. I've tried it, and it actually works; you tell your wallet an address to send to and an amount (or scan a QR code) and press "send" and the money is ready to spend in the recipient's wallet in about a second - with no fees deducted. Instead of using hashing power to break ties, the network uses voting power voluntarily assigned; every Nano wallet appoints a "representative" node, and the voting power of a node is the sum of the balance of the wallets appointing it. Wallets can change what node is their representative instantly by sending a message to the network, so the community can easily ensure that the voting weight is widely spread to avoid anybody having too much power, and debates about protocol changes can be resolved by letting users choose which nodes (running different versions of the software) they give their voting weight to.

It's not all perfect, however. As transactions are free and fast, an attacker can spam the system by creating a bunch of wallets and shuffling tiny amounts of money between them, burdening the network with validating and storing those transactions. As part of the countermeasures against that, transactions submitted by wallets need to have a small proof-of-work attached - meaning that you DO need to burn CPU cycles to make transactions. The amount of CPU work needed depends on the load on the network, to automatically raise the cost of transactions based on how many transactions per second the system can sustain; so will rising legitimate demand outpace the improvements in node hardware and hosting, until the proof-of-work cost of a transaction becomes excessive? Will spammers continue to find ways around the limitations and overload the network (as I write this in March 2021, Nano is recovering from a recent spam attack that has delayed transactions for days, while the developers work on some cunning new algorithms to prevent it happening again)?

And, like any currency whose price is set by the market, Nano will attract speculators, leading to price volatility, which as at the very least an inconvenience to its use as an actual currency.

But it's already allowing some interesting applications. WeNano is a... game of sorts? It's a smartphone-based Nano wallet, but its primary feature is that one can create Pokestop-esque "spots" based on geographical locations on Earth, to which people can donate nano, and then people who are within a certain distance of that spot can claim some of it (subject to a rate limit). The spots also have a chat function, and can act as trading hubs for classified ads paid in Nano, and there's some business integration thing for accepting Nano payments I've not looked into. Spots have been created by people wanting to promote Nano, and as a way to send aid to economically unstable countries (you don't need to be near a location to create a spot there or donate money to it); and presumably, if Nano becomes more widespread, businesses will place spots at their locations to attract footfall. Only a payment system with zero fees could make such a system practical, given the small size of the amounts of money involved. And, to my great relief, it's showing takeup in actual payment applications, such as the Wirex debit card and Kappture point-of-sale payment systems.

Nano isn't the only consensus algorithm without mining, though - there's also the Avalanche algorithm, which looks promising but hasn't built the community of people and applications that Nano has. I have high hopes for it, though!

So - Bitcoin must die, as it's failed to become a useful financial system, and is now just wasting resources on mining. The technology of distributed consensus has moved on, and Bitcoin (and its many clones) are just propelled forwards now by sheer inertia.

Lambda bodies in Scheme (by )

So, if you look at a recent Scheme standard such as R7RS, you'll see that the body of a lambda expression is defined as <definition>* <expression>* <tail expression>; zero or more internal definitions, zero or more expressions evaluated purely for their side-effects and the results discarded, and a tail expression whose evaluation result is the "return value" of the resulting procedure.

I used to find myself using the internal definitions as a kind of let*, writing procedures like so:

(lambda (foo) (define a ...some expression involving foo...) (define b ...some expression involving a and/or foo...) ...some final expression involving all three...)

But the nested defines looked wrong to me, and if I was to follow the specification exactly, I couldn't intersperse side-effecting expressions such as logging or assertions amongst them. And handling exceptional cases with if involved having to create nested blocks with begin.

For many cases, and-let* was my salvation; it works like let*, creating a series of definitions that are inside the lexical scope of all previous definitions, but also aborting the chain if any definition expression returns #f. It also lets you have expressions in the chain that are just there as guard conditions; if they return #f then the chain is aborted there and #f returned, but otherwise the result isn't bound to anything. I would sometimes embed debug logging and asserts as side-effects within expressions that returned #t to avoid aborting the chain, but that was ugly:

(and-let* ((a ...some expression...) (_1 (begin (printf "DEBUG\n") #t)) (_2 (begin (assert (odd? a)) #t))) ...)

And sometimes #f values are meaningful to me and shouldn't abort the whole thing. So I often end up writing code like this:

(let* ((a ...) (b ...)) (printf "DEBUG\n") (assert ...) (if ... (let* ((c ...) (d ...)) ...) ...))

And the indentation slowly creeps across the page...

However, I think I have a much neater solution!

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Death Head (by )

For the last year - maybe a little more I have felt that I am dying - I don't mean the ageing existential dread - I mean the feeling that my blood was thickening and clogging, as if it had hooks and barbs, but that if I was to get cut it would just bleed and bleed and bleed, that my heart was struggling with every beat but that there were so many of them that it might explode with the effort instead. My lungs have been fire, my ribs still hurt to breath as if I am breathing nothing but acidic smoke or drowning. My back hurts in new and unexpected places and this dull ache reminds me of the infected kidneys and sure enough my water works are... not right. My head often feels like it is literally being crushed or that ice water and electricity are somehow being poured into the brain casing. Then there are my muscles - so week, and crampy, twisting into painful shapes if not just the extremities going numb or tingling sometimes changing colour to match. My body feels like it has been shutting down whilst running the engine at full throttle. I actually feel like I am vibrating sometimes, my sternum is sore and even between my ribs... if I cough its like there are bands of barbed wire wrapped around too tight. And my eyes feel like they are being pushed out of my head by thumbs pressing in from the inside of my skull. My bones sometimes feel like they are splitting apart and even my teeth and scalp hurt. This is of course all on top of the pain I already had from old injuries, the chronic pain, migraines and the womb of doom.

It feels like I've been dying by degrees. Not helping this is the fact I do also have the existential dread - I have just had two and half years of everyone dying - so so many friends and family and the miscarriages and the almost dying myself. The spring especially this month is particularly horrendous for anniversaries and rememberings - including dad's and of course my last outing before illness and Lockdown was a funeral - the world beyond my door is filled with death.

But the absolute worst thing about all of this is that I can not dismiss it all as a panic attack - I did that in the summer and ended up being rushed into A&E - I am lucky I didn't have a proper heart attack - I am lucky once more to be alive. My heart really is struggling, I have been quiet sick since the miscarriages and then caught flu and/or covid on top. I have had seizures and my eyes are actually being pushed out of my head by the muscles at the back of them inflaming. My blood is clotting in a non good way and then not clotting when I need it to seal a wound. My breathing sucks - I sound like my dad who had COPD. My poor body is being pumped full of adrenaline so it is running at full throttle and it is tired - I am literally shaking myself apart like a poorly maintained piece of machinery.

I spent most of last year being unable to sleep flat due to my lungs and my hair keeps falling out.

I even got new allergies and warning sighs that my body was trying to reject parts of itself - like during my pregnancy with Jean - then there was the yellow skin - to go with the red blotches and weird blisters.

For 3 months last year - starting around now - I could do nothing much other than survive and since then basic parenting and washing myself have kind of taken up ever ounce of energy. My eye sight and hearing have both been affected and this too is not helping - it makes it like the world has receded from me - even with my new awesome glasses - and that is how ill I have been - I haven't even properly shown the world my fabulous sun glasses. I have been unable to write or draw or even craft - I began making tentative steps back to the things I love doing in the autumn but it seems like such a steep climb. Two weeks ago I attempted and completed my first commission since March last year - I managed it - I am starting to fight back - but it is unbelievably hard and I do not know where the bounders lay between physical illness and say - not seeing any of my friends for a year - most of them more than that as my mobility has been shot since the miscarriages.

The kids are helping me - we have started a family art club but I am feeling like the worst fail parent as my 15 yr old cooks food to feed the family whilst attempting GCSEs and the 10 yr old gets into trouble at school because they are obsessed with death and won't shut up about it. They both thought I was going to die and Mary got to see a full blown seizure and didn't know what to do and went to get help but everyone thought they were just doing a please play with me and so she came back and sat in the room telling me to stop and asking if I was ok and it was awful. And the poor Alaric too - they have had to take on everything -- including the basics of looking after my mum and trying to work and fill in the gaps of homeschool I got too tired to do - and there was a lot of it - I fell asleep in Mary's school club zoom. Alaric had the horror of watching me decline once more and feeling that everything is balanced on them and their ability to work and look after and fix and clean the house.

Alaric is somewhat crushed and I am more than aware of this and can do nothing other than attempt to make occasions out of everything. So today I am making a "Fake Away" of the King of the Golden Archers variety - so nuggets and burgers and milkshakes (yes that is me mucking around with the concept of Burger King and McDonalds!). The kids actually like helping with these events and tend to do their chores without arguing and they also know that these things sometimes get postponed if I am too ill - hell Jean got her birthday cake last week - her birthday is in August though Mary's happened on time - though her cake was rock hard in an attempt to make and not buy when too ill to really cook - she loved it and has been eating it with dairy free custard. This is how I fight back - it is a little lame that is true but then I am a lot lame.

But also the last couple of weeks the feeling I was dying started to lift. Obviously the seasons and things are changing so it could be the sunlight - but then I had the summer last year so I don't think it is that - I think that maybe all the medicine and things are working - I am classified as extremely clinically vulnerable and as such have already had my vaccine - I should have had weeks before I did but I got confused as I am trying to deal with 5 peoples worth of appointments and some of the clinics over lap. Three of the household are taking medicine and three are attending clinics - there isn't a complete overlap of the two groups either. Both kids now count as SEN I think and Jean is being supported by young carers.

A phrase keeps getting stuck in my head the Gloucester themed Beatrix Potter story - "I am worn to unravelling" - I am worn to undone - but the fight is on.

I now weigh the most I have ever weighed outside of pregnancy and that is some feet as I lost a couple of stone during the fever etc last year - so my weight has seriously been fluctuating with a 5 stone difference - I realise part of that is the thyroid meds (as in you can lit chart it to the dosage) but a lot is also my mobility (and maybe too many FakeAways coughs) and I was over weight to begin with.

Part of my fight back is trying to exercise - but seriously it is like trying to run a marathon every day when all I am trying to do is get up the stairs :/ but I am currently managing 3 odd km with crutches or half a km on the treadmill with out. I am using gaming (PokemonGo) and bribes (medals) and do gooding (charity challenges (or rather will be for this one)) to get moving again - before they went back to school the kids did PE with Joe with me and we found another youtube who does work outs to musicals (I found these easier to get into than Joes stuff that is obv aimed at the smol peeps).

This week has only involved one lot of blood tests and a panic at remortgaging - I have turned 40 and didn't get to have my big party but I got a purple coffee machine and though I am worried about the amount of waste it produces I have to say it is currently being my go to when things get too hard and it is like having a coffee shop in my home and mum only really likes coffee shop hot drinks anyway... we are struggling in every way except money at the moment - which is weird and I have to say money has definitely made a big difference and I can not lie about that - I have the home coffee shop set up and Netflix and iPlayer and Prime and Crunchy Roll and an epic gaming set up like we have never had before. But I often think that somewhere there is a me - trying to get through all of this without those things - and I have been in that place and in such a place it was impossible for me to fight back and all I could do was survive with lots of help. And so I want to help others - I have been trying - we have sent food and money to food banks, given resources to scrub hubs and the Hackspace to make PPE etc and I made halloween parcels for friends I thought might be finding things tricky but was too ill to even send Christmas greetings on line 0.o

Its swings and round about - but it is at least something and part of my fight back of me living is trying to make this world a better place.

So I am currently a Death Head but do have High Octane blood and hope a little engine over haul will help with things - it's just a little tricky as it has to be left running whilst the maintenance work is being done.

Recap - I feel/felt like I'm dying - probably because I actually was - trying to do more than survive and get myself as well as I can - have traumatised family due to the almost dying bit and not seeing any friends and family (big issue for youngest who needs kids to run around with and has been very lonely) - focus on family emotions rather than on grades or outside assessments. It is the anniversary time for lots of the deaths of people I love this month and also I will probably be hitting people up for sponsorings for charities to help get me fit because my arse is way too big. Also also all grown ups in our household have now been vaccinated first doeses for a few weeks which is an emotion boost even if it scrubbed me out for a week and a half (nothing like actual covid).

The Polyp Mixer (by )

So, on my desk I often have a desktop computer and a laptop. I've got a decent HDMI/USB KVM switch so I can flip my big monitor, keyboard and mouse between the two, and that's great.

However, I also have a hi-fi amplifier and speakers for audio output. This is hooked up to the desktop PC, and has selectable inputs, one of which is connected to a lead for the laptop - but I rarely plug the laptop in. This is because I can only select one input on the amplifier; and although I'm usually only listening to media from one device, I want to be able to hear notification pings from either. So I tend to leave the laptop on its own nasty little speakers and only have nice audio from the desktop PC.

Clearly, this sucks. Many years ago I had a cheapo mixing console that sat on my desk, with my CD player, minidisc player, and PC connected to the inputs, outputting into my amplifier; it was cool to be able to just hit play on anything and hear the result through my good speakers, and having all those knobs and sliders to play with was definitely gratifying. However, it was bulky, full of useless-to-me features like phono inputs and cross faders, and eventually died a death from being left switched on all the time.

Plus, I'd recently resolved to do more electronics, so there was only one thing to do: Make a mixer.

The Polyp Mixer

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