* Posts by David Gillies

54 posts • joined 21 Mar 2007


Boffins blow hot and cold over li-ion battery that can cut leccy car recharging to '10 mins'

David Gillies

Doesn't add up

Petrol has an energy density of 34.2 MJ/l. Flow rate on a US petrol pump is limited to 38 litres a minute, but even so that's delivering 1.3 GJ a minute or 21 MW.

Chemists bitten by Python scripts: How different OSes produced different results during test number-crunching

David Gillies

Don't go exploring in academic codebases without a pump-action shotgun and a torch

The overall quality of code in academic STEM disciplines is hair-raisingly awful. I used to get called in on occasion to help out a colleague with a particularly refractory bit of code. I think my greatest win was applying a bit of algorithmics and dropping the complexity of a routine from quintic to linearithmic which in the problem space where it was running represented five orders of magnitude speed-up (which is a month to 25 seconds).

Eco-activists arrested by Brit cops after threatening to close Heathrow with drones

David Gillies

Tarquins and Jemimas, the lot of 'em

Sod off, Swampy.

Microsoft debuts Bosque – a new programming language with no loops, inspired by TypeScript

David Gillies

Re: and here we go again

I'm rather partial to "Mit der Dummheit kämpfen Götter selbst vergebens".

Crypto exchange in court: It owes $190m to netizens after founder 'dies without telling anyone vault passwords'

David Gillies

Re: Someone had wikipedia open when they wrote that

Shamir secret sharing, which is what I'm talking about, is completely indifferent to the order in which the shares are used to unblind the secret (in fact there is no 'order', per se). For an (m, k) scheme where you need k from m it is trivial to make k = m.

I've been doing this stuff since the early 90's so a bunch of hand-waving doesn't impress me, I'm afraid.

David Gillies

There are well-known threshold schemes for secret sharing such that a key is split into, say, eight pieces, any five of which can be used to reconstitute the key. Fewer than the threshold and the secret is irrecoverable. I've even got some C++ code knocking about that implements this with nim multiplication over GF(256). I dunno what sort of shonky operation has a single point of failure like this.

And seriously, if you've got inflammatory bowel disease, is a holiday in India good idea?

Error pop-up? Don't worry, let's just get this migration done... BTW it's my day off tomorrow

David Gillies

Some things are forgivable

But bringing down a mission-critical resource because you've forgotten to renew the license is not one of them (q.v. the recent O2/Ericsson outage; I would hope multiple P45s ensued).

Spies still super upset they can't get at your encrypted comms data

David Gillies

Re: governments can always legislate

Perhaps someone should have thrown him out of a window and told him to repeal the law of gravity on the way down.

Defense Distributed starts selling gun CAD files amid court drama

David Gillies

Magical thinking

It's legal to make guns in the US. Always has been. You can build your own 3-axis CNC machine for $1000 or so, and mill a lower receiver or a trigger group to a few tens of microns tolerance. It's well within the capabilities of a hobby machinist to rifle his own barrels. Steel of a suitable grade for a gun barrel is available mail order. There are hundreds of people with maker channels on YouTube who have the requisite skillset to manufacture a firearm, which means thousands or tens of thousands total. How many guns are made by hobbyists a year? Unknown, but certainly a lot. How many have been used in the commission of a crime? If the number isn't zero, it's as close to zero as to make no difference. The intersection of the set of people who make guns and the set of people who use them to commit crimes is the empty set, as near as dammit. The people who make Viking battleaxes and two foot-long Bowie knives in their home forges aren't driving round on mopeds stabbing people.

Lawyers and politicians trying to stop hobby firearms manufacture are either ignorant or disingenuous. Claiming that gun crime will be lowered if gun blueprints are restricted is magical thinking.

HPE: Hell yeah, those job cuts worked out great… for our investors

David Gillies

Re: "Jobs are a cost, not a benefit"

Jobs being a cost to a business rather than a benefit isn't exactly controversial. It's an accounting identity. Arguing against it is like arguing against double-entry bookkeeping. If a firm can make more money (or even the same money) with fewer people, that's a GOOD thing. It's otherwise known as "increased productivity".

David Gillies

"Those job cuts worked out great for our investors". In other words they were a success by the only metric a business should have. Jobs are a cost, not a benefit.

It's 2018, and a webpage can still pwn your Windows PC – and apps can escape Hyper-V

David Gillies

When Flash is finally retired they need to seal the source code in an Inconel block, with suitable biohazard stickers, and get one of Elon Musk's BFRs to fire it into the Sun.

if dev == woman then dont_be(asshole): Stack Overflow tries again to be more friendly to non-male non-pasty coders

David Gillies


Complaining about men explaining things on a site devoted to explaining things to people working in a male-heavy field seems...curious. Actually, "wilfully perverse" is nearer the mark.

Programming languages can be hard to grasp for non-English speakers. Step forward, Bato: A Ruby port for Filipinos

David Gillies

Standards are great; that's why there are so many of them

It was a retrograde step allowing Unicode in variable names, never mind this.

Peers approve Brit film board as pr0n overlords despite concerns

David Gillies

Reality is that which, when you stop believing in it, doesn't go away

Huzzah. Another instance of politicians behaving like a cross between King Canute and Humpty Dumpty. I suppose to a politician all things must have a political/legislative solution, otherwise what is the point of their existence? But really this is tantamount to the attempt in Indiana to legislate a method for squaring the circle. Given that the set (World Population) \ (UK Population) is approximately equal to the set (Everyone), what exactly do Theresa May and her cyber-myrmidons hope to achieve? Clearly the denizens of Italy or New Zealand or Chile are not going to be thwarted by UK age verification in their quest for a crafty J. Arthur, so how, in the name of all that is holy, is this supposed to work? Have any implementation details been made public beyond a vague statement of intent?

Can't login to Skype? You're not alone. Chat app's been a bit crap for five days now

David Gillies

Linux version has been crap for weeks

The latest 8.14 release of skypeforlinux is completely non-functional, and it appears 8.12 and 8.13 don't work either. It shows nothing but a blank screen. This is on a generic Ubuntu 16.04 installation. I had to downgrade to 8.11 to get it working. Microsoft's QA is generally pretty abysmal but this takes the cake. People have been shrieking on the laughingly-titled 'support' forum for ages and the response from MS has been the square root of bugger all.

Canucks have beef with Soylent as to whether or not it's a real meal deal

David Gillies

If you eat foodstuff A in lieu of foodstuff B then foodstuff A _is_ a meal replacement, just as B would be were it eaten rather than A. If people want to consume some vile tofu concoction rather than something wholesome then that's their lookout. Unless it's actually toxic, governments have no remit to poke their noses in.

'Screaming' man fined $149 for singing 'Everybody Dance Now'

David Gillies

How does "the inside of your car" equate to "a public space"? And event if it is, why is screaming in public spaces not allowed? And haven't the Dudley Do-Rights got something a teensy bit more urgent to be doing?

Shock! Hackers for medieval caliphate are terrible coders

David Gillies

I'm glad we're telling them about the flaws in their cryptography. It reminds me of that press conference we had in 1943 when we told the Germans we'd broken Enigma.

'Don't Google Google, Googling Google is wrong', says Google

David Gillies

If you're writing for a living and don't know what 'intransitive' or 'gerund' mean then you should probably have your thumbs broken, to stop you writing sub-literate gibberish.

Google to kill its Drive file locker in two confusing ways

David Gillies

It doesn't work on Linux without a lot of grunting and squealing so it's de facto broken. Dropbox works like a charm.

Give a boffin a Xeon and a big GPU, get a new big prime number

David Gillies

Re: So "known" primes could be invalidated?

Lots of tests. Miller-Rabin, Lucas-Lehmer (for Mersenne primes), ECPP (which is deterministic) etc.

David Gillies

This is a generalised Fermat prime, which is a prime of the form a^n + 1. Fairly obviously, a has to be even for this to be a prime. Less obvious is that n has to be a power of two. There are probably an infinite number of GFPs, but only a finite number for each base a.

Wisconsin badgers Apple to cough up half a billion dollars for ripping off chip designs

David Gillies

That pseudocode's got a buffer overflow error in it.

Are you ready for the 40-zettabyte year?

David Gillies

Re: Interpolation?

Yes, that's a pretty tragic arithmetic fail on the Reg's part. f(t) = (9/5) 2^((t - 2011)/2)

Can YOU crack the Gauss uber-virus encryption?

David Gillies

Sounds like a fairly standard Kuang Grade Mk 11 penetration program.

'Young people don't want to become like us', say IT pros

David Gillies
IT Angle

IT is boring and full of spods and no-one should ever work in it

Right, now we've got that out of the way: why would I want a bunch of people coming into my profession and diluting my appeal to employers? If everyone could do what I do, then I wouldn't get paid as much. The ideal situation would be where my skill-set was so rare I could basically name my price.

NASA to work on approved sci-fi books

David Gillies

NASA is a silly fable all by itself

NASA has been essentially a fictional organisation since about 1973, so sponsoring sci-fi is really some sort of grim epistemic closure.

I was a few weeks away from birth when the first man set foot on the moon. I was three when the last one did. It angers me that now I have grey hairs and wrinkles and no other bugger's been back. It's not like it even costs that much, compared to the fire-hose of cash spent on welfare.

Got a website? Pay attention, Cookie Law will come

David Gillies

Errm, no, not necessarily

URL session tracking is fine, as long as a robust set of login criteria including remote IP address are tracked, it's blinded with a nonce value, it's hashed and it's compared every page view with the value stored in the DB. You should also use a cookie in tandem with it, which since it's for authentication isn't covered by this (admittedly braindead) legislation.

Tech resource woes won't be solved with Afghan minerals

David Gillies

Irritating Morales

Wouldn't it be easier to put Morales in an actual box? I always think that if these sinister capitalists are half as evil as the Lefties paint them then there should be a lot more Hugo Chavez's suddenly exploding than there actually are. It's almost like they act within the law or something. But that's clearly absurd.

School secretly snapped 1000s of students at home

David Gillies

Paranoia is the answer

I taped a little square of cardboard cut from a cereal box over the the lens of the camera on my MacBook. If the combined legions of Bill Jobs and the surveillance state can defeat that to see me surfing with no pants on, then good luck to 'em.

Mole-cruiser planned to attack Iranian nuke bunkers

David Gillies

This seems a bit James Bond-y

Wouldn't a 340 kT B61 Mod 7 nuke in laydown mode be a safer bet? What am I missing?

Sputnik, spaghetti and the IBM SPACE machine

David Gillies

Oh God, not the old 'back in the good old days' crap

Arr, when Oi were a lad, you'm didn't need none of yer fancy graphical user interfaces to calculate the powers of two. Aye, yer could do it in nine instructions. Now it's millions! Bloomin' madness, Oi tells yer.

Well that's us whippersnappers told then. Sure the machine might have weighed as much as a bus and cost half a million bucks, but you you could...drum roll...do the sort of wanky thing you learn how to do in first year Microprocessors Lab with a Z80 and a breadboard. Of course code was more efficient. The hardware was shite. To say you need hundreds of thousands of instructions to calculate the powers of two is ignoring the fact that those hundreds of thousands of instructions can also be used to display the results from computations that aren't so ball-achingly pointless.

One in three kids believe Google measures truthiness

David Gillies

You're not meant to know how Google ranks sites

Widespread knowledge of exactly how Google ranks things would be a gift to those charlatans who list 'SEO' on their CVs. What we do know is it has roots in spectral graph theory but with a substantial number of knobs on. If you can find me a schoolkid in Britain who knows what a graph eigenspectrum is then you win a lollipop.

Electropulse weapon fear spreads to UK politicos

David Gillies


We can rule out a terrorist organisation doing this, but the threat of a State actor deploying an EMP weapon is not an empty one. It might not be top of the list of threats, but Fractional Orbital Bombardment Systems (FOBS) have been known about for a long time. These have a strong deniability component and are also very difficult to counter. Civilian infrastructure would be very badly impacted. For example, food distribution is heavily reliant on just-in-time delivery and refrigeration, both of which would be badly hit by a significant EMP event. You don't need a multi-megaton weapon to cause a non-negligible EMP. In fact fission weapons give you more bang for your buck if you want to take out electronic infrastructure like telecomms and computer equipment. A big thermonuke will be better for knocking out power distribution systems. Both are hard to safeguard against.

It's easy just to dismiss this as lobbyists angling for cash, but it's a real problem.

Summer debut for Judge Dredd computer smart-rifle

David Gillies


Rorke's Drift a Pyrrhic (note spelling) victory? Not hardly. 17 killed out of 139. The idea that the braver side always wins is rubbish. Who were braver at Omdurman, Kitchener's army or the Dervishes? Who were braver on Iwo Jima, the Marines or the Japanese defenders? Courage is a very important factor, but technology can produce lopsided results irrespective of the relative bravery of the combatants. It took just as much courage to fly a bomber over Germany in 1941 as in 1945, but in 1941 crews were lucky to deliver their bombload within five miles of the target (frequently they bombed the wrong country, never mind the wrong city). By war's end average targeting error was down to 300 yards, with some specialist units achieving as little as 80 yards. The difference in combat effectiveness was profound, and it was almost wholly due to technology.

I'm also a bit fed up with the assertion that US troops are mindless undeducated automatons given to panicking and shooting indiscriminately. Nothing could be further from the truth. Their NCOs, in particular, are absolutely excellent, and it is not uncommon to find, say, a SSG with a Bachelor's or even Master's degree.

PHP added to open-source NetBeans

David Gillies

Bah, humbug

You can do 90% of that bollocks in emacs if you know what you're doing.

Employees sue for unpaid Windows Vista overtime

David Gillies

I'd be tempted to call bollocks but...

...one of our guys has a six month old 64-bit AMD machine with 2G of RAM and simply task switching from, say, Photoshop to Zend Studio can take up to 30 seconds a time. I'd be a gibbering homicidal maniac after an hour or so of that nonsense. His machine is, no kidding, about a tenth the speed of the box I'm writing this on, which is a five year old 1500 MHz PIV with a gig of RAM. But then I'm running Ubuntu Dapper. I still use Mandrake 9.2 at work on an identical box and it's a sight faster. At least 25 seconds of the boot cycle is firing up the Adaptec Ultra160 SCSI card. A pure ATA configuration is POST to XDM login in 45 seconds.

Time to reject traditional database techniques?

David Gillies

Abstract vs. concrete

Amen DZ-Jay. The Relational Model is just that: a model. But it's still important. If you don't grok why 3NF is, under a not-unreasonable set of circumstances, a good structure for your DB to have then you probably shouldn't be let loose on the world of actual data. Yes, you can deviate from the model, and in the corporeal world, far from Messrs. Boyce and Codd, you probably will. But without an understanding of why the relational model was developed, diversions from it are an appeal to magic. At the very least, no new paradigm that does not incorporate the 'C' in ACID is broken.

SuperSpeed USB 3.0 spec finalised

David Gillies

@Chris C

Yeah, it's a bad idea to give external devices truly direct access to memory. So map it through virtual memory. Or you can disable the OHCI hardware mapping, albeit with an efficiency penalty. Of course if you're close enough to a machine to be plugging things into it, security is somewhat moot (unless someone cons you into hooking up a trojan device, but that's a bit too Mission Impossible to be plausible).

The real problem with USB vs 1394 is that USB is master/slave and 1394 is P2P. Unless that's going away, and I can't see how it would, real world 1394 performance is always going to exceed USB at a given nominal data rate. What does USB 2.0 really give you? Around 40-45% of nominal bandwidth in my experience. Firewire pledges to give you 97%. 45% of 4800 Mbits/s is less than 97% of 3200 Mbits/s.

Geeks whup Marine ass in Call Of Duty 5

David Gillies

Body bags?

You didn't get 'sent home' in a body bag or a coffin or a bit of blotting paper in an envelope. You were buried in theatre. The second largest US military cemetery outside Arlington, VA, is in the Philippines.

Student charged after alerting principal to server hack

David Gillies

No good deed goes unpunished

Way back in the Middle Triassic Era (1985 or so) we discovered that the sysadmin password on the school's Econet fileserver could be obtained by hitting BREAK and peeking at a few bytes in low memory. We told the IT staff this: their response was to get very shirty and move the machine to a cupboard to which they supposedly had the only key (you could have picked the lock with your thumbnail). Needless to say this slowed us down for about five minutes until one enterprising lad wrote a nifty bit of 6502 assembler that switched the Econet card in a machine into promiscuous mode and sniffed the (unencrypted) username/password packets right off the wire. This we did not report.

Dutch court convicts teens for stealing pixels

David Gillies


The intent of intellectual property rights law is to render a non-rivalrous good (such as an image of an audio CD, or a copy of a digital photograph) excludable. Non-rivalrous goods are those for which possession by one person does not prevent possession by another (rivalrous goods tend to be tangible, e.g. a car or a hamburger). Non-excludable goods are those by which there is no mechanism to prevent those who have not paid for them enjoying them. Non-rivalrous, non-excludable goods (AKA public goods) tend to be things like a beautiful sunset or a free concert in a park (the park itself is non-rivalrous and non-excludable, up to a point). The purpose of IPR is to assign a more-or-less temporary monopoly on a non-rivalrous good in an attempt to make it worthwhile for content providers to continue making new content.

If the artefact in the RPG was non-rivalrous, then (other than the assault and battery) the perpetrators would have been guilty of copyright infringement, which is usually treated as a tort (although in some jurisdictions it is liable to criminal sanction). But since the original owner relinquished his ownership of the artefact and could not subsequently enjoy it, it was rivalrous, and thus the perpetrators' actions constituted theft with violence, i.e. robbery.

Winehouse jibe wins Fringe's funniest gag

David Gillies

It's all Greek to me

Hippopotamus means 'horse of the river', so the plural should probably be something like hippoipotamos, 'horses of the river'.

And the plural of octopus is octopodes; rhinoceros, rhinocerotes.

I am reaching for my anorak.

Intel adds 22nm octo-core 'Haswell' to CPU design roadmap

David Gillies
Thumb Down

FMA? In 2012?

It's pretty pathetic that they've waited this long to add FMA to the architecture. The PowerPC 604e in my old PowerMac 8500 had that back in the mid 90's. I wrote some bitching matrix multiplication code in assembler that used it.

NetBeans 6.5 beta promises PHP simplicity

David Gillies
IT Angle

Why do you need some fancy IDE for PHP development...

...when you have emacs?

American ISP flashes phantom bandwidth cap

David Gillies

If you try to buck the market...

...the market will buck you.

Saturating my relatively thin cable connection works out to about 2/3 TB per month. That's unrealistic, but I usually run through a tenth of that at least, or 60Gb/month. Someone has to pay for that infrastructure, and that investment has to return at a rate that makes it viable. This is really quite simple: no-one in their right mind is going to invest umpty-squillion simoleons in something if it exceeds the present value of the revenue stream they rationally expect to derive from it. It's all very well crying about the fat cats capping your bandwidth, but the money has to come from somewhere. Trunk bandwidth is relatively easy to scale, but deploying fibre-to-the-kerb is very, very expensive (i.e. on the order of $100 per metre to dig the road up, lay cable, and reconstitute the surface). Switching hardware is not cheap either, and it's a constant battle of Moore's Law lowering of hardware costs vs. Parkinson's Law of ever-increasing bandwidth demand. There isn't a magic bandwidth fairy that pays for all this. Either it's paid for through government subsidy (taxes) or directly via the consumer (higher bandwidth costs) or the bandwidth you're quoted is not available (caps/contention). I fully agree that the terms of service should be as explicit as possible in detailing what the customer will receive. Having said that, the dominant driver in lower price-per-gigabyte is a strongly (and truly) competitive telecoms market, and that is one area where the US is well and truly shafted. You really want cheap broadband? Abolish the FCC.

Suprise at spelling snafu sanctions

David Gillies

My policy was zero tolerance

As a doctoral student, I used to supplement my meagre income by working as a lab assistant. There was good dosh to be made marking lab books. I took enormous pleasure in marking the idle little toads down for every spelling and grammatical error they made. There were howls of protest, naturally, but I prevailed. The fact that this was in an electronic engineering department rather than law school was neither here nor there: correct orthography and grammar are an aid to clarity and a courtesy to one's readers.

xjy: you're talking bollocks. Insisting on correct spelling and grammar is not a fetish. Allowing 'variant' spelling, punctuation etc. breaks the standard. When Microsoft do that everyone screams like a banshee. It's not that one set of spellings is inherently more logical or superior to another. It's that it's (semi-)fixed, and everyone can read the RFC (AKA OED).

Hoist the black flag and start slitting the throats of the illiterates!

Greens: Abandon economic growth to beat CO2 offshoring

David Gillies

Nukes are problematical

Nuclear power has to be of the breeder type otherwise there's not enough fuel to last. Uranium is a genuinely limited resource in the way that coal, say, is not (we've enough coal for centuries of consumption).

As for Chernobyl, it was pretty bad for the first responders who had to dump bags of sand on the exposed core, but subsequent deaths over a wider area are almost statistically undetectable. And that accident is the only one of its type ever to have occurred.

The Green fascists are among the most repellent people on the planet. If tomorrow a non-polluting, abundant energy source was discovered, they'd be horrified. At heart they just don't like people very much.

Want to buy Jacqui Smith's ID?

David Gillies

Burn it! Burn it all!

If the technology providers are compensated (which they probably should be as they have been acting in good faith, no matter the perniciousness of the ID card scheme in general), then part of the deal must be the surrender of all documentation, electronic and paper, that the providers have gathered and created. This means every memo, every private note, every back of the envelope sketch, every design document, every CD, every backup tape, every hard drive in every computer that has been used to work on the project. Once all this has been obtained, it must be securely destroyed (papers shredded and burnt, hard drives disassembled and the platters smelted down to slag etc.). This way the hurdle to reimposing the scheme when Labour eventually get back in will be as large as it is this time, thereby postponing its implementation until they steer the country into the ditch again and get voted out.

Fire hazard icon for the lovely bonfire we need to make of this Stasi-like proposal.



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