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Boeing Told To Replace Cockpit Screens Affected By Wi-Fi

brambus Re:How the fuck are those screens built? (142 comments)

That's what we have shielding for. All modern digital signaling cabling worth a damn is shielded end-to-end. Now not all on-board electronics in consumer products is shielded, true, but pretty much all of the electronics on board of an airplane is. The screens you see on flight decks are housed in separate grounded metal cases, and all cabling going to/from them is shielded as well. My guess is either your 1W UHF transmitter does a lot more than 1W output, or your electronics is so badly shielded, it's a wonder it's working at all. Another possibility would be interference through the power supply. Cell phones have 1-2W UHF transmitters and I just checked, yep, I can have a phone conversation while working at my computer desk.

about 2 months ago
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Boeing Told To Replace Cockpit Screens Affected By Wi-Fi

brambus Re:How the fuck are those screens built? (142 comments)

Depends on which screen you're talking about. For the primary flight displays, they can just be LCD screens connected to an in-panel computer. The FMS and similar stand-alone things are self-contained computers connected to a data bus. However, all of these components are housed in separate grounded metal cases with shielded wiring going to them, so it shouldn't be a problem in the first place.

about 2 months ago
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Boeing Told To Replace Cockpit Screens Affected By Wi-Fi

brambus Re:How the fuck are those screens built? (142 comments)

I've got 3 cell phones sitting 3 inches beneath my LCD screen all doing wifi & GSM and nothing has ever happened. I've had dozens of tablets sitting on a single desk, all going wifi at full blast downloading firmware updates and nothing happened to other screens around them. I've never ever seen wifi being a problem for the power and control electronics of an LCD screen. So I'm still utterly mystified - what the hell did they do? How could they have induced a radio signal so strong as to get the screens to blank out (presumably by frying the power electronics in them, can't imagine any other obvious way).

about 2 months ago
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Boeing Told To Replace Cockpit Screens Affected By Wi-Fi

brambus Re:How the fuck are those screens built? (142 comments)

Might interest you: with speakers, it only interferes if you're inducing it into a pre-amplified line (where the signal levels of the wifi and the regular audio line are comparable and amplified together). Once past that, the audio signal is so strong that any induced wifi noise is essentially imperceptible. For example, a rather powerful antenna signal is about -40 dBmW, whereas audio amp output power level is approximately +40dBmW (for a ~10W speaker). That's a good 80 dB of delta, or about the difference between a whisper in a really, really quiet room at 6 feet (30 dB) and a jet at takeoff (110 dB).
ISS radiation is rather different - it's ionizing, i.e. the individual particles are powerful enough to knock electrons off of atoms. Radio signals aren't like that, they can only interact with materials by inducing minuscule electric currents by EM field interactions - you'd see that as line noise. While line noise is real enough, I can't imagine how it could be causing any trouble inside of a freakin' LCD screen and causing it to blank out. The only way I can imagine that to happen is if you literally fry the power electronics by excessive induced currents and the only way to do that is by a really, really powerful EM signal (in the kW range at really close proximity). Either that or Honeywell is making LCD screens with some really shitty electronics.

about 2 months ago
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Boeing Told To Replace Cockpit Screens Affected By Wi-Fi

brambus How the fuck are those screens built? (142 comments)

I have never ever heard of wifi interfering with an LCD screen. What did they do to them to get them to blank out? Stick them 1 inch in front of a directional 1kW magnetron?

about 2 months ago
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Trouble In Branson-Land, As Would-Be Space Tourists Get Antsy Over Delays

brambus Re:Expectations (77 comments)

Your weight estimates could be correct but there is no way you're gonna fit a 140-seat glider in the Falcon 9 fairings.

Of course it won't and I explicitly said to replace the entire second stage as well. I would have hoped it to be obvious that I was talking about reengineering large parts of the system.

Anyways 5 minute weightless suborbital flight is so 1961. I would just make a stretched version of Dragon that seats 20 people (no cargo) and send them into orbit for $50k each.

Or to Mars for perhaps $500k, I agree. I was just thinking out loud about the possibilities here, just to show that Virgin Galactic's system is an overpriced toy that could be done much cheaper by the likes of SpaceX.

about 2 months ago
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Trouble In Branson-Land, As Would-Be Space Tourists Get Antsy Over Delays

brambus Re:Expectations (77 comments)

Real zero-g (not Vomit Comet or theme park rides) would be pretty damn cool.

Well, the Vomit Comet is exactly the same as LEO zero-g, it's just much shorter. All the Virgin Galactic guys are doing is extending that time from 30s to 300s. And at tremendous cost, I might add.
As for 140 people for a suborbital flight on Falcon 9, that sounds about right, maybe even a bit pessimistic. By my reckoning, the second stage with propellant and max payload masses somewhere in the vicinity of 100 tons, more than the MTOW of a Boeing 737-800 and at that mass, the first stage is enough to give them around 2 km/s at burnout and an arc of well above 100km. And that includes the spare fuel to fly the spent booster back to the launch pad and land it, so no loss there either. So replace the entire second stage & payload with a hypersonic glider and you're done, basically. It might even be conceivably possible to use this to actually travel somewhere at hypersonic speeds without having to muck about with all that ramjet/scramjet business, though I'm not sure it'd be worth it.
Assuming capital costs per flight of $1M (20% of which is fuel, the rest being O&M, equipment amortization and profit), one such ticket could cost as little as ~$5k. Not chump change by any means, but still 20x lower than what Virgin Galactic are charging. It's about 1st class-type money on some long-haul flights.

about 2 months ago
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Liquid Sponges Extract Hydrogen From Water

brambus Re:Electrolysis still required, says TFA (113 comments)

It's still an interesting article. It seems they've found a way of cheaply producing ammonia from hydrogen. Not sure they meant ammonia exactly, but they mention "liquid-based inorganic fuel" and later talk about how ammonia is important for fertilizer, so I'm kinda guessing that's what they're making. Ammonia can then be used to either make fertilizer, liquid fuel substitutes and a bunch of other interesting processes.

about 3 months ago
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Liquid Sponges Extract Hydrogen From Water

brambus Electrolysis still required, says TFA (113 comments)

The process uses a liquid that allows the hydrogen to be locked up in a liquid-based inorganic fuel. By using a liquid sponge known as a redox mediator that can soak up electrons and acid we’ve been able to create a system where hydrogen can be produced in a separate chamber without any additional energy input after the electrolysis of water takes place.

about 3 months ago
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If Tesla Can Run Its Gigafactory On 100% Renewables, Why Can't Others?

brambus Re:Not just Reno (444 comments)

He focused on energy sources, and his point that the increase in usage of brown coal is neglegtible, is correct.

In that respect, that is correct, the increase might indeed be just noise.

You focus on TWh production of elictricity, where you clearly see there is a noticeable increase in terra watt hours of electricity produced ... however no one can deduce how much more brown coal was used for that.

This data is pretty hard to come by, I agree, so I had to make some assumptions (elaborated below). Can you cite your sources?

so bottom line the "record usage" of brown coal is still nearly 20% below the 1990 level (in primary energy) and roughly 10% below 1990 level in electric power production

While it is true that some efficiency offsets might be made, your numbers simply do not add up to the graph Dunkelfalke linked. It lists lignite at 3201 TJ in 1990 and 1645 TJ in 2012. That is not "[usage] of brown coal is still nearly 20% below the 1990 level (in primary energy)", that is a 50% reduction in primary energy. All of that also happened before the year 2000 - since then, pretty much no reduction in lignite use has occurred. If powerplant efficiency were indeed rising while electrical generation remained mostly flat during the 2000-2011 period, that would imply that a rising proportion of that input lignite energy (which flatlined during that time period too) is being used for heating and other uses. However that doesn't appear to be the case either (coal use outside of electricity is falling rapidly) - this leads me to believe that there hasn't been such a dramatic increase in efficiency as to be able to confidently say that the recent increase in generation is due to an increase in powerplant efficiency. Also, how can you claim use in electrical generation is 10% below 1990, when even you said yourself just a few moments before that "no one can deduce how much more brown coal was used for that". I'd really appreciate if you could cite your sources, that would allow us to clear up the situation. If you have access to figures on lignite consumption by coal fired power plants, that would be great. Otherwise, the only reliable thing we can say is that electrical generation from lignite is at an all time high since 1990.

about 3 months ago
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If Tesla Can Run Its Gigafactory On 100% Renewables, Why Can't Others?

brambus Re:Not just Reno (444 comments)

Stop spreading lies.

Maybe you should start with your own advice. The poster was referring to electrical generation here, not overall energy use. Your graph is for overall energy use (and I'm not sure about the proportions there either, they seem a bit off). You might have been clued into that by the units being petajoules (customarily used for overall energy production) not watthours (customarily used for electrical generation). Another thing that might have ticked you off is that mineral oil is a good 1/3 the energy share there. And natural gas about 1/4. In actual fact, when you look at the right graphs, in electrical generation, oil accounts for a meager 1% and gas about 11%. In relative proportions lignite has remained mostly stable since 1990, however in absolutes, 2013 (161 TWh) was indeed a record year since 1990 (171 TWh). Hard coal has also picked up in the last 5 years.

about 3 months ago
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The State of ZFS On Linux

brambus Re:above, below, and at the same level. ZFS is eve (370 comments)

I think you misunderstood my reply. I was replying to the poster talking about iSCSI having to be implemented in ZFS. That's what I was addressing.
You talk about a different thing altogether - ZFS backing. The zvol-on-another-zpool solution should work, although performance will suck. The zvol-on-the-same-zpool solution can and will hang for obvious reasons.

about 3 months ago
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The State of ZFS On Linux

brambus Re:Several others posting say that risks corruptio (370 comments)

I was talking about iSCSI support, not how the ZFS themselves pools are built. Yes, ZFS *does* prefer raw disk backing (due to certain management simplifications), but it does not need it. In fact, it's quite possible and people do frequently run ZFS on top of RAID arrays.

about 3 months ago
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The State of ZFS On Linux

brambus Re:above, below, and at the same level. ZFS is eve (370 comments)

I've confirmed it by actually reading the source code. Even a quick look at the manpage will tell you the same:

# touch /export/lun/0
# sbdadm create-lu -s 10g /export/lun/0 # file backing
# sbdadm create-lu /dev/rdsk/c1t1d0s0 # raw disk backing

about 3 months ago
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The State of ZFS On Linux

brambus Re:Proformance (370 comments)

Keep perspective. Are you really going to build a box like that with just one 2 GHz quad-core CPU?
I have pushed 4GB/s through a SAS SSD array on ZFS, but even so I maxed out on other stuff way before the CPU and much less checksumming ever began to be an issue (e.g. had to go through two LSI SAS 9200-8e HBAs, because one maxes out the PCI-e 2.0 x8 lanes; with two HBAs I maxed out on the two 6G SAS links to my JBOD). That the point of my post. I've yet to see a system which is constrained by the checksumming in any meaningful way.

about 3 months ago
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The State of ZFS On Linux

brambus Re:License mismatch (370 comments)

Sun still had closed bits in the OS kernel when OpenSolaris was CDDL'd, so GPL was a non-starter because of GPL's "infectious" nature of spreading to all source that makes up a project. CDDL is more permissive in this - it simply forces you to keep the free bits that you got free, but doesn't expand to anything outside of the source files you got.

about 3 months ago
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The State of ZFS On Linux

brambus Re:above, below, and at the same level. ZFS is eve (370 comments)

iSCSI doesn't need to be baked into ZFS, in fact, even on Illumos it isn't. It's in a completely different subsystem and will happily work with any block device as its backend storage (be it a physical drive, a ZFS zvol, a loopback block device or anything else, really).

about 3 months ago
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The State of ZFS On Linux

brambus Re:Magic (370 comments)

it updated zfs code, updated a disk format encoding but you could not revert it

You can thank your package maintainer for this. ZFS never ever ever upgrades the on-disk format silently. You always have to do a manual "zpool upgrade" to do it. It'll tell you when a pool's format is out of date in "zpool status", but it'll never do the upgrade by itself.

updating a disk image format and not allowing n-1 version of o/s to read it is a huge design mistake and I'm not sure I understand the reasoning behind it, but until that is changed, I won't run zfs

Again, this is not ZFS' fault, it's your package maintainer for auto-upgrading all your imported zpools. ZFS never does this by itself.

about 3 months ago
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The State of ZFS On Linux

brambus Re:Proformance (370 comments)

The overhead is barely there at all. I've measured the performance of the default fletcher4 checksum on a modest 2GHz Core 2 CPU and it comes to around 4GB/s/core. Now given that most CPUs now come with 4 or more cores, in order to get the checksum to be 10% of CPU overhead, you'd have to do be doing around 1.2GB/s of I/O. Needless to say, you're not ever going to get that even for fairly high-performance boxes.

about 3 months ago
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New NRC Rule Supports Indefinite Storage of Nuclear Waste

brambus Re:On site transmutation (191 comments)

What answer? You gave a few links to wikipedia with zero analysis to support it. You claim shit like "obviously we can get some energy back from the steam turbines too" without actually knowing and showing that doing so is feasible.
Look, it's really simple. Give your best case analysis for what you propose to do. No links to wikipedia and vague statements like "seems your main technical objection is being worked out with a 780 KW beam for spallation". Tell me exactly how you propose this to be done and how that adds up quantitatively. How much power, in what accelerators, how much would such a system cost and how would you propose we construct it. No more evading. Talk to the point.

about 3 months ago

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