* Posts by Robert Sneddon

390 posts • joined 14 Dec 2007

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Surface Studio 2: The Vulture rakes a talon over Microsoft's latest box of desktop delight

Robert Sneddon

Re: Hmmmmm!

Regardless, how long ago did anyone actually have a PC with only 1GB of memory?

I've got a Windows tablet with Win 10 Home on it, 1GB of RAM and an Atom CPU. Does that count? It's not fast but it runs.

Musk shows off the latest power plant for Starship, replaces Tesla CFO with a millennial

Robert Sneddon

Methane?

The Raptor engine is/was supposed to be liquid methane/liquid oxygen rather than LOX/RP (kerosene) like the Falcon engines. Is there any mention whether the test and final launch version of these engines will move to this new fuel?

Comparison of the Raptor to the MIGHTY F1!!! is not a good one -- the F1 was a dog, engineering-wise, very low efficiency and rather crude. The better rocket engine of the time was the Soviet RD-170 which was more efficient, produced more thrust and could be throttled and gimballed in flight. Cut-down versions of the RD-170 still fly today, even powering American launchers such as the Atlas V which uses the twin-nozzle RD-180.

I'm just not sure the computer works here – the energy is all wrong

Robert Sneddon

Magazine competition

Some computing magazine back in the day held a competition for the best free-gift piece of tat they could stick on the front cover as a giveaway. Someone came up with the Handy-Dandy Magnetic Floppy Disk Holder. It had a sticky pad to mount it on the side of the computer CRT, as a twofer.

Your mates vape. Your boss quit smoking. You promised to quit in 2019. But how will Big Tobacco give it up?

Robert Sneddon

Re: John Grisham was 'ere

Banksie's "The Business" is worth a read -- it's not actually science-fiction so it's not published under the name "Iain M. Banks" if you try to hunt down a copy.

Robert Sneddon

Hospitals

Many hospitals ban smoking anywhere on their property nowadays. A big hospital nearby has a large free-standing sign outside the main entrance which spells out the rules about not smoking. People go behind the large sign and out of sight of the CCTV cameras covering the entrance to light up.

Robert Sneddon

Dopes

I know one middle-aged guy who went from smoking cannabis (on regular visits to Amsterdam, not at home here in the UK because it's illegal here and he wouldn't do a thing like that honest) to smoking cannabis mixed with tobacco because he liked the extra boost from the nicotine to smoking cigarettes because he got addicted to the nicotine. He still smokes cannabis but he can't afford do do it as much as he used to because he's got a three-packs-of-ciggies-a-week habit to pay for.

Robert Sneddon

Re: John Grisham was 'ere

Well, if "John Grisham" was actually "Iain Banks" and "The Firm" was titled "The Business" you'd be right.

The patented device in question was a disposable one-shot package designed to deliver a measured standard dose of [something] nasally, looking forward to the day cocaine would be legal. Of course patents expire after a time so patenting such a device and not having cocaine sales and use become legal shortly thereafter (by lobbying, bribery or just buying assorted legislatures) is pointless.

Expired cert... Really? #O2down meltdown shows we should fear bungles and bugs more than hackers

Robert Sneddon

Not-so-hidden subsidies

One "subsidy" mobile and other network infrastructure companies got from HMG was an abbreviated planning process to dig holes, run cable and build towers everywhere. I can see the point of doing that but it's something that would otherwise cost them lots of cash and stretch the time to market hence their ability to bill customers for new services.

Blighty: We spent £1bn on Galileo and all we got was this lousy T-shirt

Robert Sneddon

GPS and EMP

Nuclear EMP is unlikely to damage the GPS satellite constellation, or Beidou or GLONASS or Galileo either. The satellites in question orbit at an altitude of 20,000 km or so, far enough out so that any terrestrial or even stratospheric nuke bursts could damage them. They're already radiation-hardened given their operational environment which is another reason they're quite durable in the face of such energy-directed effects.

They fly in widely-separated orbits to provide maximum coverage on Earth with close to the minimum number of satellites and that means attempts to attack a complete satellite constellation directly is tricky since they'd need to be hunted down one by one, just about. I've seen unattributed statements that in a real hot war GPS could be knocked out quite quickly by the Other Side but there were no details on how this might be done.

Robert Sneddon

Re: Trident

The test flights of Trident used GPS to monitor the missile's operation, not to control it in flight. It's kind of obvious, really, it wouldn't be a test of the inertial guidance system, a key component of the missile if they relied on GPS just for the test flights and just hoped the INU worked if, God forbid, it was ever used in anger.

There have been over 150 test flights of Trident D5 missiles over the years, nearly all have flown successfully. A few have failed, not a surprise there.

There's a lot of other military kit in use by British forces that does use GPS and we have access to the encrypted high-accuracy GPS data for that purpose as part of NATO. We can, of course, be locked out of that access if the US so chooses. They have changed their minds on this before and they control the system with no-one else allowed input. Galileo is a civilian global positioning system with military applications as a secondary benefit so access to the encrypted high-accuracy data it provides can be purchased for use for things like autolanding airliners and harbour manoeuvering of ferries etc.

What we're losing by leaving the EU is a place at the table deciding how Galileo is developed in the future and contracts to build the secure parts for it and we're no longer on the preferred supplier list for things like satellite components and integration since it's an EU project and EU-based companies will have first dibs rather than, say, SSTL.

Robert Sneddon

Trident

The Trident missiles don't use GPS since they spend their time underwater a lot and GPS signals don't penetrate seawater very well. In flight after launch they use an internal inertial guidance system and in space at the top of their ballistic trajectory they use a star tracker system for final course changes before their descent to glory.

Amazon's homegrown 2.3GHz 64-bit Graviton processor was very nearly an AMD Arm CPU

Robert Sneddon

Power consumption

There was no mention of how the power consumption of these chips compares to, say, a glow-in-the-dark 165W Xeon. That's been a major factor for server centre siting and operations for a while now. If AWS are saving money on their power bills while still able to deliver enough data processing capacity with these chips then it's probably a commercial win for them. I don't think Intel are going to be losing much sleep or orders for Xeon deliveries from server builders over this though.

Nikola Tesla's greatest challenge: He could measure electricity but not stupidity

Robert Sneddon

Fred Pohl

Upvoted for a reference to a visionary story written over sixty years ago but oh so relevant in today's world. Who says SF can't predict the future?

Robert Sneddon

Re: It wasn't that long ago

Boulton and Watt are on the current British £50 banknote so replacing them with scientists or engineers on the new polymer note which will supercede the existing note isn't that much of a step.

US and UK Amazon workers get a wage hike – maybe they'll go to the movies, by themselves

Robert Sneddon

Bernie Sanders

The legislation he was proposing wouldn't have survived the process of being turned into law, like most proposed legislation does. Bernie's legislative record as a long-term Washington insider (30 years a Senator) is pitiful. It looked good though, as many things do from a distance.

I've worked in an Amazon warehouse in the past -- the fulfilment side of things was staffed by a few long-term employees usually acting as foremen and team leaders training and supervising workers, the rest were folks who weren't going to be there three months later because it wasn't a career for them, just something to make some money from (and to keep the DWP off their backs for a bit). I stayed for a couple of weeks and bailed because the commute became impossible due to a road bridge being shut for emergency repairs but I'd not have been there myself in three months time regardless.

It doesn't pay well because it's not a demanding job, intellectually or otherwise and the staffing requirements are a race to the bottom. It does provide paid work for a lot of folks who would struggle in other roles for various reasons, at least until the robots take over. The extra money will be nice though.

A flash of inspiration sees techie get dirty to fix hospital's woes

Robert Sneddon

My Site Induction Safety Briefing

They showed us a map of the bits they had been able to find[1] after someone dropped a large slab of high explosive on a concrete walkway. Apparently from eye-witnesses some distance away, it didn't go off until it was picked up -- the post-mortem (so to speak) engineering analysis suggested the edge of the slab scraped along the concrete and that was sufficient.

[1]There were two people involved, they only found one head.

I've seen the future of consumer AI, and it doesn't have one

Robert Sneddon

Re: CLIPPY!

No one misses Clippy.

You can, if you fail to get your sights re-zeroed down at the range often enough.

UK getting ready to go it alone on Galileo

Robert Sneddon

New CVNs don't have steam to spare

The new Ford-class nuclear carriers are electric-drive like most if not all modern warships. They don't have external steam generators to provide propulsion steam and catapult steam like the earlier CVNs, instead their self-contained nuclear reactor installations produce electricity for the propeller drive motors in the same way the British QE carriers have gas-turbine generator sets for propulsion and, indeed, the new British Astute subs which do the same thing although they're nuclear-powered.

The Ford-class carriers have two 300MW output reactors compared to the previous generation of similar-sized carriers which had two 150MW reactors. Part of that extra capacity is to drive the EMALS catapults (though they use a storage system to provide the instantaneous 30-50MW of electricity needed for a launch) but a lot of the extra capacity is because there are a lot more sparkly bits in a big ship like that than there used to be, plus redundancy of course.

Robert Sneddon

Trust

Long-range weapon systems like ICBMs and cruise missiles don't use GPS as a primary source of targetting information because it can be spoofed close to the target. They use internal accelerometer systems and, in the case of ballistic missiles a star-tracking system to provide final course correction before re-entry.

GPS can be used before launch of mobile weapons such as cruise missiles to initialise the on-board tracking systems but that's done in friendly territory where spoofing is less likely to occur since it relies on flooding the local area with carefully degraded GPS signals for the receiver to pick up and accept as valid data.

Robert Sneddon

Not enough energy

The first aircraft carrier catapults were actually powered by compressed air, not steam, and presumably something similar is still possible.

A typical aircraft of the 1910-20 period suitable for launch from an aircraft carrier would weigh a couple of tonnes with a low takeoff speed. A mission-ready F-35B or indeed any existing strike fighter can weigh up to 25 tonnes loaded for a mission and can require the plane to be travelling at over 150mph at the end of the catapult to clear the front of the carrier successfully and avoid becoming a sea dart (tm).

Finding space to fit air or steam plant into the existing carrier spaces and the surplus power to produce stored energy to launch aircraft using some kind of catapult wasn't really a goer for the QE-class carriers. The EMALS electromagnetic launcher was a possibility, it has a lot of good features but it also sucks a lot of electrical power and the QE-class gas turbine engines weren't specced to produce bursts of surplus energy of that size. Some kind of battery/spinning storage might work but again there wasn't much space left to put it somewhere in the hull and if it ever broke then nothing could be launched at all.

Robert Sneddon

Ground stations

There are more than two ground stations involved in the Galileo error correction system and the Falklands and Ascencion Islands stations can be replaced to fill in gaps since we're leaving the EU and the Galileo programme.

As for a "simple treaty", go ahead. Getting 27 separate national governments to change their minds on this exclusivity because we want to stay in just this bit of the EU after March 2019 is going to be tricky.

Robert Sneddon

Money all spent

The funding of the Galileo work was spent in the countries that contributed it, basically. The money that Britain has put into the project has already been paid to British companies building the Giove test satellites and other parts of the system. There's no funds left to refund. Since Britain is leaving the EU and thus the Galileo project we won't be contributing any more funds to it but we won't be getting contracts to build any more of it either. Out means out, as the Leave campaign said.

Surprise! VAT, customs likely to get a bit trickier in a Brexit no-deal world

Robert Sneddon

Truck licences

The EU allows only a limited number of trucks from countries outside the EU to enter and move around the EU collecting and delivering materials, goods etc. At the moment something like 75,000 British trucks each year do this, carrying just-in-time parts to and from factories on either side of the Channel as well as transporting food and the like. There are no problems with the trucks and drivers doing this since they're in the EU and work under standard EU rules for safety, driver training, licencing and other factors.

A typical large non-EU nation like Turkey will get about 1200 permits for trucks to operate cross-border in and out of the EU. If we're lucky we'll get about the same number of permits to go around the entire British haulage industry after Brexit.

Robert Sneddon

Landfill = green

A lot of waste material is plastic derived from oil or natural gas. Landfilling it would be better then the usual alternative of burning it as a "renewable" energy source and dumping the resultant CO2 into the atmosphere. Paper and cardboard is also a source of CO2 if burned and would also be better landfilled.

Sure the paper and plastic would eventually rot underground to produce carbon-rich gases like CO and maybe CH4 but it would take hundreds or even thousands of years for that gas to develop and escape into the atmosphere.

Google shaves half a gig off Android Poundland Edition

Robert Sneddon

Science of Cambridge Mk14

Still got mine, it still works. I hacked a lot of push-buttons onto it since the original rubber-sheet keyboard thing was a PITA to use.

Declassified files reveal how pre-WW2 Brits smashed Russian crypto

Robert Sneddon

PR(A)NG

Pseudo-random number generators (PRNGs) aren't truly random, indeed they are peculiarly non-random. e.g. if the number 5 comes out it is followed by 24 every time. A PRNG will produce some or all of the numbers in its range exactly once before repeating the sequence but the repeat will be an exact copy of the first sequence and so on. PRNGs have their uses but cryptography isn't one of them.

OTOH I know of a system that used radio noise to produce a RNG key for a digital device that had to be provably "random" under licencing restrictions -- slot machines.

Fukushima reactors lend exotic nuclear finish to California's wines

Robert Sneddon

Re: 1952?

Pu-239 has a longish half-life, about 24,000 years. Any Pu-239 created in the early days of atomic weapons development in the mid-40s will not have experienced much radioactive decay -- one online calculator I've used suggests that about 0.2% of that original Pu-239 would have decayed into U-235.

Robert Sneddon

Re: 1952?

That's because the plutonium 239 turns into uranium 235

Uh? I'm puzzled as to the process that makes Pu-239 into U-235... Fission of U-235 produces a zoo of isotopes, nearly all of them radioactive. The proportions of each isotope follow something called the M-curve in terms of atomic mass with most of them being roughly half of 235. The commonly-produced longer-lived ones like Cesium-137 (half-life about 30 years) are the ones to worry about since the short-lived ones are gone in a few milliseconds, days or weeks, for example Iodine-131, half-life 8.5 days.

The same thing applies to the fission of Pu-239 nuclei, most products are roughly half of 239 which is damn close but not exactly the same as the fission of U-235. It's one way to characterise a nuclear test, to determine whether it was a uranium or plutonium core (there are other ways and there are methods to obscure the results if the tester doesn't want others to find out easily).

TL;DR -- the Gadget exploded at Trinity in July 1945 released Cs-137 into the atmosphere just like Little Boy did over Hiroshima in early August a month later. Saying that, some Cs-137 probably escaped into the wild from the startup of the Chicago Pile-1 reactor back in December 1942.

https://en.wikipedia.org/wiki/Fission_product_yield

Windows Server 2019 tweaked to stop it getting clock-blocked

Robert Sneddon

Testing it out

There was a leap second added a couple of years ago. I happened to be at the local Hacklab that New Year's Eve and someone set up a Linux box command line job to see what it would report as the clock ticked over from 23:59:59 to 00:00:00. We didn't see 23:59:60 as we should have.

Crooks swipe plutonium, cesium from US govt nuke wranglers' car. And yes, it's still missing

Robert Sneddon

Almost all nukes are portable, the ones dropped from bombers or fired on the top of missiles. There were British nuclear land-mines (meant to be kept at working temperature by chickens) which weren't portable but that's about all.

Man-portable? You're probably thinking of the Atomic Demolitions Munition series of nukes which could be carried by two people, deployed off the back of a small truck to demolish bridges and other structures. The US took them out of service back in the 80s once the Soviet Union fell apart and the threat of a Red Army road race to the Atlantic ports evaporated. There's nothing left in the toy locker that's small either in size or yield, even for tactical use.

Robert Sneddon

Uh, no.

Extremely toxic as in radical amputation required.

Actually no. Plutonium is a lot less toxic than, say, arsenic or beryllium. There's a lot of scare stories about Pu and of course similar fairy-tales about uranium (see Gulf War Syndrome for a worked example) but generally they're not a real biochemical threat or even a serious radiological worry. There's a "hot particle" theory that's mostly wild imagination crossed with movie-script physics and biology about how a particle of Pu could cause instant lung cancer. Healthy lungs are good at clearing dust and particles out if the airways and such a particle wouldn't stay resident in the lungs for more than a couple of days.

People who worked on the Manhattan Project back in the 1940, doing things in a hurry without modern Elf and Safety rules got Pu in cuts and grazes, inhaled and ingested Pu particles etc. and they were mostly OK decades later.

Robert Sneddon

Re: I work in the field

And isn't hard to extract the fun stuff from, just illegal.

Not even illegal, just chemical engineering. I read a report a few years back about an American undergrad who, for extra credit in his Chem Eng course got some low-grade uranium ore from a desert location by hunting for it with a Geiger counter. He refined it into yellowcake, the minehead product of uranium producers and got the extra course credits for the effort. He gave a couple of grams of the stuff in a glass phial to a student friend (not a Chem Eng undergrad). His friend's college dorm found out about this incredibly dangerous material, called in the NRC and law enforcement and kicked him out.

Science fiction legend Harlan Ellison ends his short time on Earth

Robert Sneddon

Harlan and Book Signings

Harlan was a writer for hire for a lot of his early career and he wrote some stinkers to pay the rent. He had a standing offer to buy back copies of some of those books if you brought them to somewhere he was appearing, like a book signing or a convention. After handing over some money (five bucks in my case, about thirty years ago) he would then gleefully destroy the book there and then.

Now Microsoft ports Windows 10, Linux to homegrown CPU design

Robert Sneddon

Experiment(al)

I don't see MS building commercial silicon based on this experimental work -- the Fine Article mentioned that after several years of work the current silicon is Xilink FPGAs running at 50MHz. They're a long way from a taped-out, tested and optimised design coming off a 10nm fab somewhere in quantity 100,000. The rest of the project is cycle-accurate simulations, Matrix-style "silicon" that isn't available off-the-shelf to anyone.

I can see them using what they've learned from developing this CPU design in future compiler and OS releases running on existing commodity silicon like x86 and ARM, assuming it can be made to work on that sort of classic CPU architecture and makes a noticeable difference in speed, security etc.

User spent 20 minutes trying to move mouse cursor, without success

Robert Sneddon

Re: Done that a bunch of times

A while back I was picking up some exhaust bits for my van from a local branch of a well-known chain of repair depots (beings with K, ends in fit) near the end of the business day. The guy on the counter was filling out forms rather than typing stuff into the workshop's online system. I bent my head around and saw a classic BSOD on the monitor.

"Do you know something about these things then? I got to write all the jobs up tonight 'cause it's bust. I'll be here for ages."

I nodded, gave the keyboard a three-fingered salute and after it thought about it for a minute the screen cleared and displayed an NT4WS login followed by a burst of activity from the modem followed by a functional data entry screen followed by a thirty quid discount off my order.

Dixons Carphone 'fesses to mega-breach: Probes 'attempt to compromise' 5.9m payment cards

Robert Sneddon

Useful fallbacks

postmaster@example.com always works. Me@127.0.0.1 is also worth trying.

Don’t talk to the ATM, young man, it’s just a machine and there’s nobody inside

Robert Sneddon

Pentesting

One time-honoured method of penetration testing a building is to carry some plumber's tools and mutter into a phone about the toilets as you approach the front desk. They'll call a lift for you, hold doors open for you, get you a cup of tea. Any office building over three stories tall has something wrong with the toilets.

Galileo, Galileo, Galileo, off you go: Snout of UK space forcibly removed from EU satellite trough

Robert Sneddon

Re: Skewed thinking

"Since the US dropped Selective Availability the case for a separate EU positioning system is less obvious"

Galileo is more accurate than GPS. The Galileo constellation covers more of the sky, especially in northern latitudes compared to the US-centric GPS system so it's easier to get a lock in built-up areas in European cities which are somewhat shaded from the various positioning satellites already in orbit.

It's Pi day: Care to stuff a brand new Raspberry one in your wallet?

Robert Sneddon

Re: Dates

"YYYY-MM-DD is a fabulous, sensible format."

Until you run into the Year 9999 problem. The only solution really is to count in femtoseconds out to about 10^200 years, the time when the last proton decays and the Universe expires, voiding all warranties and support contracts. After that it's Someone Else's Problem.

Organic battery tech could work better than a woolly hat in the cold

Robert Sneddon

Re: Which makes me think...

An early electric car made by Enfield used a separate LPG heater with a small fuel tank to heat the passenger compartment when it got too cold. I think most modern electric cars use the cooling loops for the motor and battery pack to heat the cabin with top-ups from the battery as needed.

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

Robert Sneddon

Re: 68000 versus 8086

ULAs weren't available in the early 1980s hence the IBM's use of lots of TTL to get it to work at all. Yes the 68000 eventually got a number of dedicated support chips but that was a long time after the original IBM PC was in production. I think the 68008 (the cut-down 8-bit-bus version of the full-sized 68k) which any 68k-based IBM desktop would have used was also late.

The 68000's bus was asynchronous, relying on a data-available strobe from each peripheral and memory controller which was tricky to make work with regular clocked peripherals. It had advantages, it made mixing slow and fast devices on the CPU bus easy but it didn't work easily with the simpler existing chip families, not even the Motorola 8-bit designs like the 6800. It could be bodged to do so (I designed circuitry to do just that back in the day) but it took extra glue logic and wasn't elegant.

IBM had to go with what they could buy in predictable quantity numbers at a decent price that would do the job and the 68000 just wasn't there when the door closed.

Robert Sneddon

68000 versus 8086

The 68000 wasn't ready for production when IBM were looking for a CPU for the desktop PC (Back in the early 80s I played around with a dev board where the 68k was clocked down to 4MHz, half its rated speed). Motorola also didn't have the support chips needed to build a complete system so everything like interrupt controllers, floppy disc controllers, UARTs, graphics chip drivers etc. would have to be implemented with lots of TTL.

The 8086 (and the version IBM actually used, the 8-bit-bus 8088) was designed to use existing 8080-series support chips, being bus-compatible with the older device. In addition its internal registers and addressing modes were also backwards-compatible so migrating existing programs from 8080-series CP/M versions was piss-easy. The 68000's "clean sheet" instruction set and internal register structure meant everything would have to be rewritten from scratch, especially boot code, low-level device drivers and kernel code.

Voyager 1 fires thrusters last used in 1980 – and they worked!

Robert Sneddon

Reaction wheels

Reaction wheels and gyros only work to alter the orientation of a spacecraft while they are spinning. Slow them down to a stop to save electricity and wear and tear on the bearing etc. and the spacecraft settles back into its original orientation. They don't last forever -- the Hubble space telescope has/had multiple redundant sets of reaction wheels used for tracking during observations and most of them have stopped working IIRC.

Expend some mass through a thruster, the spacecraft will rotate. Fire off some more mass in the opposite direction, it will stop rotating and stay in its new orientation.

Escrow you, Apple! Ireland expects Cupertino to cough up to €13bn

Robert Sneddon

Fines AND back payments

Any fines that might be levied are on top of the requirement to repay the taxes owed as well if the case goes against them.

Apple may well try and find another low-tax EU country to shuffle all their EU earnings through but Ireland is already one of the lowest corporate tax environments in the EU. The beef is that they weren't charging Apple the same rate of tax as everyone else and now they have to do so, and claim the back taxes too.

Want a new HDMI cable? No? Bad luck. You'll need one for HDMI 2.1

Robert Sneddon

HDCP?

As far as I know DisplayPort doesn't support HDCP for DRM copy protection.

I've got a 4k monitor, a first-generation model which only supports HDMI 1.2 = 4k at 30fps. I run it using DisplayPort for computer use (4k at 60fps) but I can't feed it from a 4k media source that outputs HDMI 1.4 or better. There don't seem to be low-cost media devices that output DisplayPort as standard.

There are rumours of converter boxes that can accept HDMI 1.4 4k60fps singals and output via DisplayPort but they are rumours only, it appears.

F-35s grounded by spares shortage

Robert Sneddon

Versailles treaty

The Versailles treaty was not rigorously enforced after the mid-1920s and the removal of French and Belgian troops from the Ruhr after it was occupied in 1923. The Germans remilitarised the Rhineland in 1936 against the treaty obligations and the Allies did nothing. They stopped paying reparations and the Allies did very little. By the mid-1930s the treaty was effectively waste paper. The Germans hated it primarily because it promoted the idea that they had started the war, something their right-wing vehemently denied all the way up to the start of WWII (part of the Dolchstosslegende).

On the other hand, almost within living memory of the 1919 settlement, the Prussians had imposed identical financial reparations (5 billion gold marks, the modern equivalent of $350 billion or so) on the defeated French after the war of 1871 and the French had paid the sum demanded completely in less than years. The flood of free money into the Prussian and German economy caused a property bubble that caused a recession for almost twenty years.

Li-ion batteries blow up because they breed nanowire crystals

Robert Sneddon

Nickel-Iron

Ni-Fe batteries aren't obsolete but they are heckuva expensive for some reason. They have a market niche for static long-term operation (decades or more) and they have good charge and discharge characteristics, they can be discharged repeatedly to zero without taking damage. However they cost ten times as much as Li-ion and they're bulky and heavy so they don't fit the mobile and vehicle markets which is where the money and research is currently going into.

Arm isn't saying IoT firmware sucks but it's writing a free secure BIOS for device makers

Robert Sneddon

Re: IoT Ain't There Without A VM.

"So, when will ARM ship M-family processors with VM hardware & instruction support? Is TrustZone fully equivalent?"

VM, crypto modules, hardware for secure boot etc. means more core bloat in the design which eats into the low-cost low-power part of the ARM sales advantage against other CPUs which already have these options but cost more and consume more power. You had most if not all of those facilities on the x86 CPU platform you were working on, if ARM want to match that capability for security purposes they're going to have to go head-to-head with existing products in terms of cost and power consumption.

Yes, British F-35 engines must be sent to Turkey for overhaul

Robert Sneddon

Speed of sound

The speed of sound in a gas varies with temperature, hardly with pressure (there is a slight variation since gases are not Ideal). It also varies depending on the gas -- the speed of sound is a lot higher in hydrogen at room temperature than air (1270m/s vs. 330m/s). The interstellar medium is mostly hydrogen, I believe so even if it's a lot cooler than Earth's biosphere then the speed of sound will still be a lot higher higher than in air at STP.

The guns with the highest muzzle velocity use hot hydrogen behind the projectiles since the speed of sound is the limiting factor determining the final muzzle velocity (i.e. the speed of the pressure pulse behind the projectile).

Robert Sneddon

Warthogs

During Desert Storm F-16s and other strike fighter aircraft flew a lot more missions deep into an Iraq air defence network which had been degraded by sanctions and pinpoint strikes, and they only lost 6 aircraft too facing greater threats.

Putting a plane within range of the other guy's heavy machine guns and light cannon in today's wars is stupid, basically. The Warthog may be "badass" but it's slow (all-out max about 700km/hr, a Boeing 737's cruise speed is about 900km/hr), it's difficult to fly low and shoot straight at the same time, the fleet is ageing out rapidly -- the last new A-10 airframe came off the production line in 1984 -- and generally it's only suitable for attacking forces that can't shoot back. Even then it's a logistical nightmare, having to be based well forward close to enemy forces to make it available quickly if needed for CAS and it requires a lot of custom kit like the ammo loader system for the GAU/8 gun to keep it operational.

As for "surviving multiple hits", any significant damage to an aircraft is a mission kill, it has to break off and attempt to return to base before bad shit happens. Yes I know, "titanium bathtub" and all that but it should never get hit by light cannon fire at all. The day of the bayonet charge, the horse cavalry and the battleship is over and it's time for the Warthog to go too.

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