* Posts by hugo tyson

372 posts • joined 20 Apr 2007


Solving a big, yellow IT problem: If it's not wearing hi-vis, I don't trust it

hugo tyson

Brownouts (fnarr fnarr)

I used to work somewhere that had one of the first HP/PA HPUX systems (I think, mid 1990s) outside the USA. They were very pleased with their automatic voltage sensing auto-switching PSU that just worked with 110V or 240V or whatever, supposedly. We were in Barrington Hall, in a village. At least the place had 3-phase supply.

We had brownouts.... we also had power cuts and the supply was delicate enough that procedure was to turn off everything we could when it went dark; sysadmins would then come round and turn it on one by one so that the startup load of all the discs didn't happen all at once and trip it out again.

But in some shapes of brownout, the HP/PA machine's clever PSU auto-switched to 110V. Great. But it was very slow at switching back to 240V when the mains came back up, and failed with smoke. Every time the project was delayed a week whilst they shipped another PSU; after some months they sent a better PSU without the stupid in it, and all was well.

Geneticists throw hands in the air, change gene naming rules to finally stop Microsoft Excel eating their data

hugo tyson

64-bit intengers too....

It's not just dates; I had a customer saying "your data is useless" when they had opened the CSV in Excel, just to

check it wasn't corrupted, AND SAVED IT BACK. Thus corrupting it....

All the 64-bit integers were now double floats. Thus removing the significance.

These were 32 bits of latitude, and 32 of longitude, in 1/2^32 units of a full circle.

Handily that resolution is about a centimetre, we were very pleased with that encoding scheme for mapping.....

The reluctant log trawler: The buck stops with the back-end

hugo tyson

Multiple tabs doom

I learnt long ago that trying to do two things in parallel in tabs is *dangerous*.

Bit of a windfall, not sure what to do, so of course I wanted to open one fixed-rate fixed-term saving account, and one variable-rate to spread the risk of inflation.

Filling in many tedious details in two windows next to each other. Disaster; neither opened successfully, but at least neither debited my money either. (TBH it could have been so long ago that "apply online" meant "fill in a form online and we send you forms, you sign and return a cheque" - I can't remember)

At least Amazon seems to get that right these days.... I'd still be scared to try it with real finance.

When a deleted primary device file only takes 20 mins out of your maintenance window, but a whole year off your lifespan

hugo tyson

Re: Serious question from a non Unix person

"Delete" only deletes an entry in a directory (folder) and decrements the reference count on the actual bag-o-bits file. When the file has no references and no open handles on it, *then* the file is deleted.

Normally, in the simple case, of course "rm foo" just removes folder entry foo, and also the bag-o-bits underlying it at the same time....

Four more years! Four more years! Svelte Linux desktop Xfce gets first big update since 2015

hugo tyson

Yep, xfce via xubuntu for me every time, for years. Works fine on older smaller laptops, but I don't know of anything I'd want from it on bigger machines.

SpaceX reveals chain of events that caused the unplanned disassembly of Crew Dragon capsule

hugo tyson

Re: From a safe distance. In proper safety gear

Upvote for "Ignition!" - everyone should read Ignition! - it's terrifying what they tried in the Cold War.

hugo tyson

Freshly shattered titanium?

Maybe, like aluminium, all the titanium anyone sees, or any chemical touches, is actually a thin layer of transparent titanium oxide already.

It requires freshly-shattered titanium in an oxygen-free environment for the oxidiser to set it on fire, maybe?

Blue Monday: Efforts to inspire teamwork with swears back-fires for n00b team manager

hugo tyson

Management omission...

If only the bosses had said they were going to abstract from the database to make training examples, then the workers would have known why the guidelines on cleanliness of made-up names. That's the root cause of the problem right there.

Reminds me of test software I wrote for the very first ARM CPUs at (troubled Cambridge micro-maker) Acorn in the 1980s. Testing that the silicon actually did the ISA, as it were. It was for use only within our small friendly team. So one of the fail messages was "Shifter fucked". But later ARM span out, became a monster success, and was shipping that test suite as binaries. You can guess the rest.

Why does that website take forever to load? Clues: Three syllables, starts with a J, rhymes with crock of sh...

hugo tyson
Black Helicopters

On the cusp...

I have JS enabled and a blacklist of sites where it's disabled (in $Chrome). The disabled sites are the more or less the newspapers that I read daily. I experimented with globally-disabling JS and having a whitelist instead; it was about the same size so I didn't take that plan further. But it was soooo close, very much on the cusp.

I wonder how long it'll be before disabled JS is popular enough - or the default on enough browsers - that we'll see nagware like the "you appear to have an Ad Blocker..." saying "Please enable JaveScript to continue..." :-(

Did you know that iOS ad clicks cost more than Android? These scammers did

hugo tyson

Cost to me?

If all it costs the infected user is a little battery life, they won't notice either, and it's not an unreasonable decision to decide not to care?

AFAICT there's no other downside to the victim, is there?

Brit boffins build 'quantum compass'... say goodbye to those old GPS gizmos, possibly

hugo tyson

Re: "AIUI the military signal has a faster chipping rate with longer PRN "

Civilian GPS really is 1023 chips/cycle so the PRN shift-and-feedback 10-bit register never has to go through zero, 'cos if it did it would stay on zero. Repeating every millisecond (nominally, subject to doppler and clock errors).

About the mil signal, the really long cycle time is for security only - makes it really hard to find unless you have pre-loaded tracking data somehow, from that encrypted almanac as you say. But that aspect doesn't add at all to accuracy: only a higher chipping rate can do that, which as you say is 10x the civvy version. But only 10x, so each chip is ~30m. You might get 30cm correlation data out of that.

The ionospheric correction - the naive algorithmic one (ramps up linearly from 0600 local to noon, ramps down from 1800 local to midnight, times cosine something I think) in civilian GPS standards docs anyway - is under 10m, ISTR it being 5m to 7m max usually. So the naive model is good for a system whose overall accuracy is 5-10m anyway. Interesting that of course the mil system needs better Iono corrections from the ephemerides (I guess) 'cos its native accuracy is higher.

But it can never be reliably that accurate. I had a GPS antenna on the windowsill of an office about 15m up. It saw half the sky OK. I generally got accurate positions, being of course the position of the antenna not my computer connected to it. But when it rained, a sloping roof across the road turned into a radio reflector and I could "see" much of the other half of the sky too. Great! you might think, but it saw the new sky with extra path length, since the new signals went across the street and back extra. So my positions were solved for about 10m away, in the middle of the road. Ain't nuthin' you can do to prevent that sort of situation short of rejecting some signals in the solver - but which ones? - whatever your chipping rate and correlation accuracy, it can still be fooled by reflections.

hugo tyson

Re: GPS accuracy

You're conflating turning off selective availability (SA), which they did 'cos of various gulf wars, and making access to the military signals available. They didn't do the latter.

SA dithered the civilian signals to cause a wandering inaccuracy of several hundred meters. It is defeated by using a fixed ground station to work out the current offset, and delivering the difference data to receivers - this is Differential GPS. So people were working around it anyway.

With SA turned off as it has now been for decades, the civilian signals are still only accurate to a few metres 'cos the chipping rate of the PRN code (orthogonal CDMA code) is 1023 chips per millisecond, so each chip is about 300 metres long. Curve fitting to multiple correlation results gives timing to fractional chips but it's inherently noisy - so you might get actual results accurate to 10s of meters (30ths of microseconds). Solving with many satellites reduces the combined error, sure, but it's stlll meters not centimeters.

AIUI the military signal has a faster chipping rate with longer PRN sequences and so it's inherently more accurate because the basic unit of "knowing when the signal is" which you have if you're managing to track the signal at all, can be not about a microsecond = 300m, but a fraction of that. It's a 10th of that - 30m - in the old versions, and it's not in wikipedia for the latest actually secret stuff. I only ever worked on civilian receivers, so had no need to look at the mil stuff.

Russian rocket goes BOOM again – this time with a crew on it

hugo tyson

Re: Performed as expected... SRB abort

The Shuttle SRBs nearly had a "become safe after lighting" feature which involved explosive detachment of the top cap of both SRBs, so they both became like one of those new wanky double-ended lightsabers. With no net thrust, was the idea.

This was in case only one of them ignited, to prevent making a catherine wheel out of the whole affair... it wasn't implemented; possibly the top-end flame thrower would have killed everyone anyway, and they got SRB ignition reliable enough that they always lit both, or neither.

TalkTalk shrugs off moaning customers to claim 80,000 more

hugo tyson
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Re: Why? Just Why?

Me too; 79,9xx kB/s from advertised 80Mb FTTC. It's fine (touch wood).

Had one issue, it was a rusty wire just outdoors, where the pair changes to thinner indoor wire.

I should have looked closer myself, but they were fine and not too slow about coming.

America's forgotten space station and a mission tinged with urine, we salute you

hugo tyson

Re: Men in Black

That's the book - thanks, your memory's better than mine.

hugo tyson
Black Helicopters

Men in Black

I read in a public, academic book, that when Skylab launched, NASA was keen to see what the wrongly/party deployed solar panels, and associated damage, looked like. The NRO had secret spy satellites, of the kind which drop a film cartridge when it's been filled, which NASA were not allowed to know about, nor anyone else really. Apparently NASA had a visit from sunglasses and dark suits, who said "Your top 4 engineers on this, in here, now; no-one else. Here are some photographs. You may look at them for 15 minutes. They do not leave this room. We were never here, you never saw this." And it helped them decide that fixing it on-orbit was feasible, and what they needed to take and do. According to one of those NASA engineers.

Time to ditch the front door key? Nest's new wireless smart lock is surprisingly convenient

hugo tyson

Why's it mounted on the door?

Why do they keep mounting locks on the door? If it were mounted on/in the frame, with the striker plate/box in the door, then you could run wires to it for power and cat5, solving several problems....

How machine-learning code turns a mirror on its sexist, racist masters

hugo tyson

No Asian, African texts?

Problem might be there are few extensive texts in suitable form for input, which were written by Asians or Africans about the white men, nor by woman of any kind, which reflect their attitudes to the cruel imperious selfish arrogant white European male, no? Just choosing English for the language used puts that bias on the whole thing.

Can't see an easy solution, but maybe it could be improved by pre-biasing the corpus the other way.

Hold the phone: Mystery fake cell towers spotted slurping comms around Washington DC

hugo tyson

Legality is itself location-sensitive

It's legal according to US law for the US to use StingRay in non-US places; doesn't mean it's legal according to the law of those places. What it means is that the US government won't act to prevent itself using such tech outside the US.

Remember, according to US law, US law applies over the entire universe. Really.

What's silent but violent and costs $250m? Yes, it's Lockheed Martin's super-quiet, supersonic X-plane for NASA

hugo tyson

Re: Only Mach 1.4?

Pretty sure the boom is anywhere the craft passes at faster than mach 1, not just at transition.

Nest reveals the first truly connected home

hugo tyson

Re: Doorbell as a cost center.

But are they ever actually *welcome* ? Unless you're expecting them by prior arrangement.

Fancy owning a two-seat Second World War Messerschmitt fighter?

hugo tyson

Re: Why were inverted V12s popular with the Germans?

Ta. So mostly packaging then. But surely it's a dry sump *because* it's inverted, the causality direction I mean. Anyway thanks, I see what you mean.

hugo tyson

Why were inverted V12s popular with the Germans?

As there are nerds here, I'll ask: I've never managed to work out why "we" consistently used V12s the "right" way up, and the Luftwaffe consistently - so it seems - used inverted V12s. Are there advantages to inverted beyond the view from the cockpit - but then you need longer undercarriage; I'd have thought having a single sump is better, but OTOH do you get more reliable valve lubrication if it's all inverted? But what prevents oil pooling in the underside of the pistons besides their violent motion?

Tsk-tsk, fat cat Softcat: Milk-slurping reseller taken to court

hugo tyson

History repeating itself...

There was a time when "troubled Cambridge micro-maker" Acorn Computers couldn't get milk delivered because of unpaid invoices with every last one of the local newsagents and dairies. Because of idiot finance bods going "oh this little one doesn't matter"...

Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign

hugo tyson

Re: Hmmm... @AC Might not even leak data

The leak may not even be data, it could be as small as a timing change from the spec-ex path taking longer to fault, or not, allowing the attacker to probe the kernel space for not/valid pages - so defeating to an extent the kernel memory-map randomisation? Worse might be a spec-ex branch on spec-read secret data which affects timing similarly, without directly exposing the data itself.

Blade Runner 2049: Back to the Future – the movies that showed us what's to come

hugo tyson

Video Conferencing

Star Trek has videoconferencing that actually works properly. Still beyond our grasp....

I've arrived on Mars. Argggh, my back!

hugo tyson

How much decrease in muscle mass?

The sentence in the article is a bit mangled, do you mean the muscle cross-sectional area decreased to about 80% of what it was originally, the range being 86% in the best case and 72% in the worst case?

Or if it decreased by 86%-72% does that mean only 14% to 28% remained (which seems terrifying)?

GPS spoofing can put Yik Yak in a flap

hugo tyson

Hardly GPS spoofing

Hardly GPS spoofing is it? Just setting your location somewhere else. Fake location, fair enough.

Turing, Hauser, Sinclair – haunt computing's Cambridge A-team stamping ground

hugo tyson

Details, details...

In Cambridge it's a Court not a Quad; Quads are from The Other Place ;-)

But yes it's a great photo, so of its time.

Re the pic on the steps of 4a Market Hill, L-R David Johnson-Davies ("DJD"), Hermann, Chris Curry, Roger (now Sophie) Wilson, Nick Toop, holding an Acorn Atom. 4a MH was never an ARM office; only Acorn.

The Turing Room in King's is the College Computer Room as I understand it; named after the great man. But I don't think there's any implication that he lived in that basement room, it's a cellar. As a Fellow he might well have lived in the rooms above, though.

Great British Great Bake Off gets new judge

hugo tyson

Needs a proper critic

Why can't we have Brian Sewell? Aside from him being dead. And his bro George as sidekick to introduce some gritty realism.

The field at the centre of the universe: Cambridge's outdoor pulsar pusher

hugo tyson
Thumb Up


Just: thanks for the article - great stuff, I enjoyed that day out enormously; thanks to Cambridge Wireless too of course.

Milk IN the teapot: Innovation or abomination?

hugo tyson
Thumb Up

Perfect optimisation

We did exactly that - but in a proper teapot, I'll grant - at (later to be troubled) Cambridge micro-maker Acorn Computers in the early 1980s.

Brit chip biz ARM legs it to Softbank for $32bn

hugo tyson

Re: Apple will never own ARM (again)

I thought the licence those big players have ("foundry") lets them re-implement the hardware as they like, but absolutely not fork the instruction set and software interface generally (ISA, eg. cache behaviour) to make sure code portability can never be sacrificed. Intel IIRC learnt this when they acquired DEC and its Xscale designs, and tried to fiddle with the ISA, and found they couldn't because the ISA is copyrighted in some way separate from the IP licence.

WTF because this is a complete surprise. I could believe it's as simple as SB having a huge mound of cash and looking for the best possible investment, as ARM is starting to work in servers too, and the IoT bubble.

DARPA's 'flying wing' drone inches closer to lift-off

hugo tyson

Mmmm.... contra rotating....

But not as sexy as a Fairey Gannet, eh?

Model's horrific rape case may limit crucial online free speech law

hugo tyson

Re: law enforcement?

It's not clear from the report whether the "agencies" or indeed actual agencies had to be registered or vetted in any way. Is it?

hugo tyson

Different law?

This does seem separate from the protection afforded to common-carrier-like websites in that law, in that this is abusive readers/consumers of the site, who cause no change to its state -- not abusive speech published via/though/on the site. Tricky.

It does suggest that reader accounts should strongly be vetted, in such cases, and contacts should be only through the site so that they are logged in an evidence-worthy fashion. Otherwise it's just like telling Facebook everything with entirely public access.

Watch: SpaceX finally lands Falcon rocket on robo-barge in one piece

hugo tyson

Yay indeed!

I'll drink to that; wups, I was anyway!

Regular Fast Radio Burst detected outside our galaxy

hugo tyson


...as it's not regular.

$17 smartwatch sends something to random Chinese IP address

hugo tyson

It's the app that leaks, right?

But do you need the app to use the watch or is it just like the "drivers CD" you get with every little toy that nobody needs because they're actually standard USB devices? Put another way, if it's a proper BlueTooth device it'll use the standard BT profiles to be remote-control for the phone functions, and not need no steenkin' app.

Course it could just be checking for updates...

Oh TechNation. Britain's got tech talent. Just not like this

hugo tyson

Tool users vs tool makers

They're failing to distinguish people who use IT as a tool to run their business - ie. have a website and email and maybe an online shop - and those who actually make new IT/digital things. And the people who make websites for businesses, or set up their email, are somewhere in between, IMHO rather closer to users.

Like people who make TV ads or soap operas are not innovating in the photography business.

It's like classifying every business which acquired a shiny new landline in the 1920s and '30s as a telecoms business. (Might have the decades wrong but YKWIM)

It's like saying that B&Q is part of the steel industry because they sell spanners.

'I bet Russian hackers weren't expecting their target to suck so epically hard as this'

hugo tyson


So what's wrong with

for ( u = 100; u < 200; u-- ) { ... }

I think I have seen this as a fix! :-(

Lights out! Newbie IT manager's dark basement trip

hugo tyson

Re: Ah Diesel Generators

One job, the modal cause of genuine fire alarm evacuations was "the temperature is too high in the detached generator building" - following the regular testing... especially in summer.

You've seen things people wouldn't believe – so tell us your programming horrors

hugo tyson

So much fun....

Once we shipped some embedded software as a relocatable binary to a customer. It needed to be started with some workspace memory. They were getting nowhere. So I went to Japan, and spent two days working out how the hell to debug/single-step in their useless environment, to find they had started it giving it the memory where the code was, as its own workspace. It ran just fine, initialising its memory, until it shot itself in the head by overwriting the code that was doing the initialising...

In PostScript, double-slash is a meaningful token, prefix to a name for immediate evaluation. It's used a lot in the bootstrap, itself written in PS, of a PostScript-compatible interpreter. Trivial example

/inc { 1 //add } def

For one reason or another, the bootstrap source was macro pre-processed. This was fine until the C-preprocessor - for it was he! - enabled C++ comments by default. Most of the bootstrap disappeared.

Re. sweary messages and customers: in the 1980s, at Acorn, I wrote tests for the very first ARM CPUs, even before we had silicon back - to check the various emulators, and to test in simulation the chip layout before tape-out, to test the chips when they came back. One said - or rather didn't, because it worked OK - "Shifter fucked!" in the error case. This was all lovely, and the same unit tests were still used 10-15 years later by ARM. They even shipped them to customers (making their own ARMs) as binaries. This was lovely too. Until one customer somehow managed to make chips whose shifter was not entirely correct...

Intel admits Skylakes can ... ... ... freeze in the middle of work

hugo tyson


is that exponent in hex. Interesting. One might wonder if it's all exponents of the form 0xNN0001 (NN > 0)

The Register's entirely serious New Year's resolutions for 2016

hugo tyson

Getting "across" the news

(you) "can get across a day's news quickly" - if you're dropping the sexism, you can use correct English and say "keep abreast of the day's news" without sniggering, rather than that revolting neologism. Or even just "catch up" ffs....

PM wheels out snoop overseer minutes before latest snoops' charter bid lands

hugo tyson
Black Helicopters

What will they log?

So what will the govmt require ISPs to log? DNS lookups? So use or - or will they snoop on DNS request packets en passent for all? Or do they log what IP addresses you open connections to, which reverse-DNS gives domains? So something like Tor or other onion router gets round it. Just curious if anyone knows, if the detail has come out yet. Because it seems likely that a determined operative could circumvent any obvious logging....

Separately, I too worry that someone out of touch will be prone to assertions about what can be done which are not realistic, such as "well force them to decrypt it" given a noisy image + allegation that it contains a steganographic code, for example. Point is old media (paper letters, morse code) are either plaintext or definitely something cryptographic. Modern media/messaging can be perfectly valid gibberish and still be your pictures/music: you can't prove the positive "there is encrypted data here" nor the negative "this is just a picture, no encrypted data present". That's what could cause the traditional legal profession's assumptions problems.

PC sales will rise again, predicts Intel, but tablets are toast

hugo tyson

Intel-based tablets

Exactly, my first thought was: Intel got the market for Intel-based tablets wrong. They did; they're not so good, so people didn't buy many,

Silicon Valley now 'illegal' in Europe: Why Schrems vs Facebook is such a biggie

hugo tyson

Re: Let me count the ways...

I agree the email example is a very poor one: by sending an email to a person you give them the right to do whatever they like with it, stupid legalese boilerplate on the end notwithstanding. And email never has been private. Of course, the public's expectation might be different, but that doesn't make it so.

A better example, and easier to understand would be: you think you order a product from an EU business. Name, address, credit card, implicitly shopping habit. Turns out their servers are in the US. They just exported your personal data without your consent.

Doctor Who storms back in fine form with Season 9 opener The Magician's Apprentice

hugo tyson


The "Handmines" is just a crap pun on landmines innit. Cute that they're like the hand-from-the-grave thing in every zombie movie, but with dalek (biological) eyes spliced in.

And my bet is it's the handmines that he's going to exterminate in the opener for Ep.2.

Typewriters suck. Yet we're infinitely richer for those irritating machines

hugo tyson

Re: <pendantry>

Pendantry? Should be bloody well hung...



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