Posts by Graham Wilson

@S4qFBxkFFg -- Need for a hermetically sealed chamber.

Helium being what it is, the only way I can see such a drive working is if the drive's platter chamber is properly hermetically sealed. This would require a chamber similar in construction to that of a light globe or radio valve which has a fully sealed envelope. Electrical connections would enter the envelope and connect to the electrodes in the same manner.

Such a connection through the glass requires a special seal where the glass must properly wet the surface of the metal wire (this can be a manufacturing problem). Perhaps also connections could be done by electrical (capacitive/magnetic) coupling through the glass or whatever non-conducting material is used for the chamber. For instance, the motor stator could be on the outside of the chamber and the rotor on the inside.

Frankly, it'll be interesting to see what they come up with, as from my experience, keeping helium in any container is somewhat of a problem.

All I hope is that these drives will be more reliable than the current batch of failures that I've had over the last couple of years.

BTW, the shingle recording method reminds me vaguely of the recording system used in VCRs where the hi-fi stereo channel is laid down under the video tracks.

@Displacement Activity -- Re: @Graham Wilson

First, I did mean to say "electromagnetic force", heavens know why I said "electromotive force"—my once lecturers would be horrified (and that error's sometimes a trick exam question).

"Hope you didn't ask the aviation experts about this." Yes, I did actually. I won't bore you with the ins and outs of the discussion except to say that weight/fuel economy is a major/principal reason for fly-by-wire but it's not the only one—another compelling one is that pilots simply like using it (as most of us have become addicted to smartphones). And there's other reasons too.

Right, conductors do have free electrons but also they have 'bound' ones. The reason the table my laptop is resting on remains solid or why one bleeds after having been bashed against a solid plate of conductive steel is because of 'bound' electrons—if you like the electronic structure of matter. I beg to differ with you about the electromagnetic force as it is much weaker than the strong force and operates over a long (theoretically infinite) range subject to the inverse square law. And that's the rub—that the electromagnetic force can induce currents at a distance from the source, apart from being why electrical stuff works, it underpins the reason for the problem of electrical interference. (Signals induced into TV antennae miles from the TV station illustrate the point—here they're wanted but unwanted ones are induced the same way).

Obviously, I'm not opposed to using electronic control systems—after all, that's my profession—but I've seen enough system failures, whether through interference or other electronic faults, to question whether ripping out a perfectly reliable and simple mechanical system only to have it replaced with a complex electronic one is the correct move. Often the answer is 'yes' but the question must be asked. Here's a simplistic illustration of how new problems arise: at present I've an annoying intermittent electronic fault in my car's dashboard and when it fails I lose everything. In older cars that I've owned when the speedometer cable broke, the simpler and less tightly coupled system meant that I still had functioning fuel and temperature gauges.

There's no doubt the electronics/control systems in the 787 are remarkable and a credit to the designers. The keyword here is reliability—key electronics consist of multiple/dual systems that function the same but which are different in design in that they've been designed by different teams/organizations under 'clean-room' conditions.

That said things still go wrong with the best designed electronic systems and sometimes finding glitches, intermittent faults and interference sources—which in the case of aircraft are highly variable as they change their environments—can be incredibly complex, especially in a system as complex as a 787. (Those who've had a PC that has locked up for no apparent reason know the problem.) Moreover, there are other well-publicised instances where electronics, which have replaced critical mechanical (but historically very reliable) systems, that have had electronic failures which have led to serious accidents. For example, it's still unclear why the electronics in the Toyota Prius accelerator failed (anyway, the public is still in the dark).

There's a final reason why I reckon it's important to have fallback in critical systems (here a different technology—mechanical backup), and that's because it's essentially impossible to do a full state analysis (analysing/checking every permutation and combination of operation) on a system as complex as 787. A state analysis on even something as simple as a domestic VCR can fail through its complexity. Here's just one example: I'm aware of a mass-produced VCR with many hundreds of thousands of units in the field where it was eventually found to fail by pressing a certain combination of buttons—but the fault was only found years after it had been released!

Certainly fly-by-wire isn't going to go disappear, but the lesson we should learn is that modern electronic systems are both new (in that we don't have a century or so experience using them), and often they're extremely complex and that sometimes they fail in unpredictable ways—in ways and at times that we least expect.

@AC -- Re: Preferred

"But even so 1-2-3 was always better than Excel."

I agree. I base that on having used most of the biggies--1-2-3, Quattro, Supercalc, Visicalc etc. Goes back as far as Visicalc on my TRS80 and Supercalc on my Godbout S100.

As with VHS vs Betamax, being 'better' depends on marketing. And irrespective of what one thinks of its software, Microsoft is a superb marketing company. Moreover, the long delay in porting 1-2-3 to Windows did it much damage.

@A.C. -- Re: Jamming / broadcast license

"RFID operates in unlicensed spectrum...."

In most jurisdictions where unlicensed spectrum exists, unlicensed use is only permitted up to a small strictly controlled power limit--100mW to 1W or so depending on service. To ensure effective jamming you may need well above this power limit, thus a license.

But as you say "Jamming may fall foul of other rules and regulations though", so there's the Catch-22--you won't be granted a license. Jamming has a long history and protocols have evolved with it. The ITU radio regulations specifically exist so that there is a peaceful coexistence between radio users and jamming goes against this ethos--hence licenses are unlikely to be granted.

It gets very messy from here. Some jurisdictions have 'secrecy provisions', which means that if you hear/receive a signal you are not allowed to act upon it unless it's meant for you. This leads to complications such as police radar--you may not be allowed to own a radar detector or the ludicrous situation where you allowed to own one but are not allowed to act upon its data--i.e. put your foot upon the brake.

In summary, radio regs are a minefield in almost every jurisdiction.

@ gordon 10 -- Re: "So they hooked it and dragged it to the surface where it died. "

The pressure at the surface is very different to its normal habitat in the deep. Thus, it would have died anyway (as do most deep-sea creatures when raised to the surface).

@melt -- Re: Delay lines

El Reg has been down this path before (which I'm sure you know):

http://forums.theregister.co.uk/forum/1/2011/01/13/edsac_rebuild_bletchley_park/

Many of us were pissed off then and our sentiment still hasn't changed--certainly not yours truly!

@CaptainHook -- Re: Buffering?

Easy and cheaply. Get a set of *old* forklift batteries for free (new ones cost a fortune). Forklift batteries are excellent as they've solid plates and even when sulphated and abused and no longer suitable for a forklift, they'll deliver many, many kilowatts.

Of course, you have to know how to 'load' them into the system. Helps muchly if you are an electronics nerd or know one.

@Vladimir Plouzhnikov -- Re: Irrespective of theory.

Right, I'm living in my hermetically sealed vehicle which is hopping about for safety--thing's ain't good here on Mars. But I've been watching the sky and earth's a spectacular messy ball-of-fire.

Better here than there.

@theodore -- Re: @Dan Paul -- Luddites UNITE!!!

Simple really, I rang up the telco and just told them to disconnect both the internet and texting services and they immediately disconnected me from them.

Those services then didn't work, it was the same as having not paid the bill and being cut off--except the phone service still worked OK.

@beemergeek - Re: WINE

Wine is OK for many apps but unfortunately too much overhead for games. Also, there's often compatibility issues and the game simply won't run.

@DougS -- Re: Shame the West isn't as proactive about antisocial phone behaviour.

"To be fair, we also did most of those things without the airplane, either."

...But certainly not WWII. My point was that society has organised truly ginormous events and done so effectively without the mobile/cell phone. If you actually want to know just how truly extensive aircraft use was in WWII then check here (start at about 06: mins in, exact reference at 06:38):

http://www.youtube.com/watch?v=hFSPHfZQpIQ&playnext=1&list=PL6F7C922213EC685A&feature=results_main

If you're really keen then you'd watch the whole video and see how the cellular radio concept was used decades before mobile phones became practically feasible.