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Comment: Re:Hilarious (Score 1) 930

by Solandri (#46466717) Attached to: How Do You Backup 20TB of Data?

You *can* plug in an external drive, it's called a complete hardware duplicate of your array

You don't even need to duplicate the array hardware. 20 TB is still within the range of a RAID enclosure. Basically a box where you plug in drives, and it gloms them together into a RAID 0/1/5/10. You then plug it into your computer with eSATA or USB 3, and your computer sees it as a single drive up to 32 TB in size (8x4TB with current drives). Do your backup, then unplug it and turn it off until your next scheduled backup.

Incidentally, TFS is a perfect example of why RAID is not a backup. Yes RAID is kinda like storing two copies. But the "two copies" are linked both virtually and physically. If you accidentally delete one copy, the other gets deleted simultaneously. If you physically damage the array, you lose both copies.

RAID is not a backup. RAID is for redundancy. If your business will lose hundreds of dollars per hour or more while the file server is down, you put the file server on a RAID array so it will continue to operate even if there's a single (or double) drive failure. i.e. It only protects against your file server going offline. You still need a separate backup.

Comment: Re:"Tell the families"? Really? (Score 1) 459

by Solandri (#46461281) Attached to: The $100,000 Device That Could Have Solved Missing Plane Mystery

Now, if you want to justify real-time transmission, check out the amount of (incidentally not paid for by the airline) search gear that has been diverted from Malaysian, Chinese, and other sources to looking for the debris. Whole bunch of ships, airplane and helicopter overflights, diversion of what, 10 satellites? That starts to make the $100k look like savings.

Well, the cost is $100k if you know ahead of time exactly which plane is going to go missing and outfit the device on just that single plane.

Obviously the real world doesn't work like that. You don't know ahead of time which plane will go missing, so you have to outfit all of them with this device. The best estimates I could find on Google were that there are about 15,000 commercial airliners in operation globally, so you're looking at a total cost of $1.5 billion.

Suddenly all the ships, airplane and helicopter overflight, diversion of 10 satellites seems like an absolute bargain. For reference, the multi-year search for AF447 and recovery cost about $40 million.

Comment: Double, triple, quadruple charging (Score 5, Informative) 74

I have a phone. It has a 4G LTE plan. It is always with me.

I have a tablet. I cannot use it simultaneously with my phone (in the sense that I'm actively doing something that consumes data with one device).

I have a laptop. I cannot use it simultaneously with my tablet and phone.

I have a car. I cannot use it simultaneously with my laptop, tablet, and phone.

Clearly the proper metric that used here is to charge for LTE data use per individual (or even per GB). Not per device. The "correct" solution here is to get your cellular data plan with your phone, and have your phone operate as a hotspot to share that data with your tablet, laptop, and car. Attempts to charge for service on a per-device basis is just double-, triple-, or quadruple-dipping by the carriers. If service is being metered per GB, this shouldn't even be an issue. Pay a nominal fee for an LTE SIM card, link it to your phone account, and add the data it uses to your monthly usage. There is absolutely no need for the device to have its own separate plan.

Comment: Re:Lessee, where's my dictionary? (Score 1) 661

by Solandri (#46458375) Attached to: 70% of U.S. Government Spending Is Writing Checks To Individuals

mandatory (adj): Obligatory; required or commanded by authority.

As the article points out, most of this is going to mandatory programs, which would be the same even if it were Romney or McCain or Sarah Fucking Palin in office.

That's the dictionary definition.

The government definition is that a mandatory program continues in perpetuity until the legislature decides to stop (or modify) it. A discretionary program must have its budget approved every year or it dies.

The government modifies spending and revenue in mandatory programs all the time. The Social Security tax rate was decreased from 13.3% (where it had been since the 1990s) to 12.3% in 2011 to try to lower the tax burden during the recession. And SS gets a cost of living allowance approved each year (usually) which increases the disbursement to recipients in response to inflation. The spending of those programs could very well have been different if a conservative had been in office.

When we hear a serious discussion of how to cut benefits (something other than "the poor should die" and "let's give it all to Wall Street, because they're so freaking responsible"), we can have an actual conversation.

Yes those are ridiculous stances to take when debating the budget. But so are "mandatory programs cannot be touched" and "the retirement age must not be increased."

Social Security isn't like a pension or 401k - where you pay money in, it goes into some account in your name earning interest, then you get the money back when you retire. Instead, your payments get disbursed to current recipients (there's about a 2-3 year buffer which is the SS fund). That means the amount you pay into it isn't the only factor. The retirement age, average lifespan, and population growth rate (ratio of workers to retirees) all become factors. The program has been run for ~70 years now in denial that these are factors, which is what's caused it to balloon to a quarter of the budget. Any realistic attempt to contain its growth (I'm not even asking to reduce it) needs to acknowledge these other factors, and modify how the program operates to zero out their effect in the long-term.

And don't even get me started on Medicare. When certain programs show consistent growth over the last several decades, you have to stop and ask yourself why those programs are growing, and what we can do to stop it to keep the budget reasonable. You don't plug your fingers into your ears and say "nah nah nah I can't hear you" any time someone tries to discuss options to contain the growth.

Comment: Re:Thoughts (Score 5, Informative) 142

It did NOT break up at altitude. Something rendered the aircraft uncontrollable. A loss of hydraulic pressure or power does this for a 777.

A loss of hydraulic pressure or power does not do this for a 777. It has a RAT (ram air turbine) which pops out in such cases. Basically a big propeller which gets turned by the wind as the plane glides at 500 mph and generates enough power rudimentary electronics (including radio) and hydraulic pressure. That's what happened with the Gimli Glider - a 767 mistakenly loaded with insufficient fuel (the original boneheaded imperial vs metric conversion foul-up before the Mars Climate Orbiter). which basically turned into a 100 ton glider when it ran out of fuel mid-flight. The RAT popped out and allowed the crew to control the plane to a safe landing. (Which of course means if this did happen on MH370, the search area needs to be much larger than where they're currently looking).

Hydraulic failure usually involves structural damage which compromises all the hydraulic lines. Most commercial aircraft have 3 independent hydraulic systems; some have 4. If there's damage which severs lines in all of those systems, the plane can "bleed" hydraulic fluid until there's not enough left to control the flight surfaces. I believe the 777 used a hybrid fly-by-wire + hydraulic system though, where pilot commands are transmitted to the flight surfaces by wire, and a hydraulic pump there moves the flight surface. So severing the hydraulic lines may have killed one control surface, but not all. (Severing the wires OTOH...)

Anyway, I'm skeptical that it broke up at altitude too. That usually generates a lot of floating debris (papers, luggage, clothing, bodies, etc.) scattered over a wide enough area that the crash area is quickly located. The pingers should be firing away so it's just a matter of one of the search boats traveling within a few miles from the plane's resting location. (KAL007 wasn't located because the Soviets knew from their radar tracks where it went down, and set up decoy pingers far away to get the U.S. and South Korea to search the wrong location).

Comment: Re:Why not nukes? (Score 3, Insightful) 108

by Solandri (#46450581) Attached to: How Engineers Are Building a Power Station At the South Pole
The overhead associated with operating a commercial nuclear power plant (maintenance, safety requirements, fuel transport and storage, etc) means they don't become economically viable until you're servicing a population of about a half million. That's what Honolulu doesn't have a nuclear plant even though it'd be almost ideal for their remote location. Currently they get most of their electricity from burning fuel oil, and consequently have the highest electricity prices in the U.S. - about $0.30/kWh vs the national average of $0.12/kWh. Cost on the islands other than Oahu is even higher (about $0.45/kWh) because they have less access to oil and have to rely more on renewables.

With a population of just under 400,000, you couldn't run a small commercial reactor full-power 24/7 as they like to be run. You'd have to ramp it up and down throughout the day, which greatly increases operational costs. In the rest of the country, nuclear provides 24/7 baseline power. Coal plants can ramp up/down more quickly, but it still takes a while so they also provide baseline power. Fluctuations in power use through the day are handled by oil and gas plants (which can ramp up/down almost instantly) and hydro (which can ramp up/down instantly).

A RTG (generates heat through nuclear decay, not an induced nuclear reaction) could work. The Soviets used to power many of their remote lighthouses with them. But the wind in Antarctica is very strong and very consistent, and would seem to be the obvious go-to energy source given the scale and remote location (minimal maintenance crew).

Comment: Re:Summary (Score 2) 147

by Solandri (#46443407) Attached to: 3 Years Later: A Fukushima Worker's Eyewitness Story
I'm an engineer by training. My natural inclination is to assume the worst and seek evidence showing that things aren't quite that bad.

Reading TFA, I was struck by how the manager seemed to assume the best and sought evidence showing things were worse. When workers told him they couldn't read the coolant water levels anymore, rather than assume the worst (the cooling water had all evaporated) and order seawater to be dumped in (killing the commercial life of the reactor), he repeatedly asked the workers if they were sure. They told him they couldn't be sure there was no water because they couldn't read the levels, and he took that to mean the water levels might be ok so he wouldn't have to make the hard decision to dump in seawater.

Comment: Re:Good luck (Score 1) 167

I would actually go even further than that. This Yik Yak app isn't causing the problem. The problem already existed - some kids think belittling and harassing other kids is ok. Yik Yak just gave them a means to carry out what they were thinking of doing without fear of consequences. It's like if you were to survey a thousand people if they thought Blacks were lazy, almost nobody would say yes. But if you asked them anonymously, a significantly larger percentage would say yes. The former survey may make you feel better about society, but the latter is a more accurate measure of what people really think. In what way does banning the latter type of survey make any sense?

So banning Yik Yak just hides the problem out of sight, it doesn't make it go away. To really fix the problem, you (schools, parents, whomever) have to drive it into kids' heads that this sort of behavior is just wrong. Everyone knows it goes on it school (e.g. the jocks vs nerds stereotype), but nobody seems to ever try to stop it. The problem goes away when the kids stop thinking the harassment posted in Yik Yak is funny or true, and start thinking the person who anonymously posted such things is an idiot.

Comment: Re:Give It Ten Years (Score 2) 109

by Solandri (#46443369) Attached to: Up To 1000 NIH Investigators Dropped Out Last Year
That would be nice if that were the way SS and Medicare actually worked. What really happens is the money you paid during your 40 years of working went to pay people who were retired while you were working (people who were retired when the SS program first started got a free ride). And in the future you'll be receiving money from the people who are working while you are retired.

Basically, it's the Asian cultural model where when the parents retire, their kids pay for their living expenses. Except on a national scale. The "entitlements" are not something you are entitled to. It's just an arbitrary allocation of a percentage of the kids' current income (currently 12.4% for SS, 2.9% for Medicare).

There's a token attempt by the accountants to make sure the numbers balance out long-term, but it's subject to things completely out of the accountants' control - like people's lifespans increasing, or couples having fewer babies. At a minimum, the retirement age needs to be scaled to keep pace with average lifespan for the numbers to balance out. But it's been stuck at 65 since the 1940s when life expectancy at birth was about 62, and life expectancy for a 50-year old was about 70. Currently the life expectancy for those ages are 78 and 81 respectively. So we have fewer people paying into SS (couples having fewer babies remember), and the people who qualify for SS collecting 3x as much money (living 3x longer in retirement) as when the program was first started. That's what's killing the budget and SS/Medicare.

Comment: Re:Austerity (Score 1) 109

by Solandri (#46443309) Attached to: Up To 1000 NIH Investigators Dropped Out Last Year

Austerity driven stupidity intentionally trying to destabilize this country. It's too bad we can't be strict constitutionalists and call up the militia to put down the insurrection or the far right fanatics, anti-science, anti-education, anti-Christian right. It really is simple: stupidity doesn't lead to innovation.

Take a good look at the graph in TFA. The biggest increase in investigators was during Clinton's second term (peak of the tech bubble) and Bush's first term (onset of recession). i.e. Bush increased science spending despite the country dropping into recession. A look at historical budgets bears this out. The biggest increase in federal funding for non-defense R&D happened during Bush's two terms.

Obama tried to continue that upward trend during his first term, but reality has set in and he's been scaling it back. We are still above the funding levels when he took office though.

Comment: Re:Prosecutors too busy to catch the real criminal (Score 1) 92

by Solandri (#46440687) Attached to: A Dispatch From Outside the Prison Holding Barrett Brown


Not saying the government hasn't been bought. But by Occam's razor, a simpler explanation is that little fish like Brown and Swartz don't have the funds to mount a persistent and comprehensive legal defense. Prosecutors see them as a way to score a quick and easy victory, compared to bringing charges against Corzine and being tied up in court for a decade or more with a questionable outcome. I'd even go so far as to say there are probably lots of Browns and Swartzes you've never heard about who are in prison. Their case didn't generate enough publicity for organizations like the EFF to catch wind and offer legal counsel.

In other words, the problem is that the legal system is too expensive. The same thing likely would have happened even if the government wasn't/isn't bought.


by Solandri (#46436617) Attached to: California District Launches Country's First All-Electric School Bus
loshwomp has already addressed the range part. I'll tackle the PV part.

Diesel has an energy density of 36 MJ/l, or 136 MJ/gallon. If you assume 12 MPG, a school bus driven 100 miles a day will consume 8.3 gallons. With a conversion efficiency of 30% (30% of the energy makes it to the pavement and moves the bus, the rest is lost as heat in the engine, transmission, and tires), that's 136 MJ/gal * 8.3 gal * 0.3 = 339 MJ of energy consumed. Or 3.4 MJ per mile.

A full-size school bus is about 2.4 meters wide by 12 meters long, so you could put about 28.8 m^2 of PV panels on top of the bus. Commercial PV panels are rated at around 135 Watts/m^2 (about 18% efficiency), 28.8 m^2 then has a peak generating capacity 3888 Watts. If the bus were driven 1 hour at noon on a sunny day, it would generate 3888 W * 3600 sec = 14 MJ. Or enough to travel 4.1 extra miles.

Capacity factor for the U.S. is about 0.145. That is, for every 1000 Watts of PV you have installed, it'll generate on average 145 Watts throughout the year after factoring in night, weather, angle of the sun, dirt on the panels between washings, etc. So those 28.8 m^2 will actually only generate 3888*0.145 = 536.8 Watts average through the day. 536.8 Watts * 1 day * 24 h/day * 3600 s/h = 36.38 MJ in a day. Or enough to move the bus 10.7 miles per day. You've paid to cover the entire top of the bus in PV panels, and over a day it's harvesting less than 11% of the energy the bus needs for its daily route.

This is what most solar proponents don't seem to get. Solar energy is very, very low density. Even if PV panels reached 100% efficiency, the dream of an electric bus driving 100 mi/day powered entirely by solar panels on its roof can't happen. Sunlight simply doesn't have enough energy density.

If you're going to go solar, you are much better off with fixed panels (either on top of buildings, or on a covering structure for the school bus parking lot). They should plug into the grid and provide electricity where it's needed. And when the the bus comes back from its route, it can plug in and get its electricity from the grid as well (from solar, wind, hydro, nuclear, gas, coal, whatever). This:
  • Combines a much larger area of PV panels while using a single voltage regulator and other electronics, reducing cost.
  • Has lower construction strength requirements since they don't need to survive constant motion, bumps, and jiggles, also reducing cost.
  • Allows the panels to contribute even if a bus happens to sit unused for several days or weeks (beyond the point where its battery is full) due to maintenance or a little thing called summer vacation.
  • Vastly simplifies maintenance as your panels are always accessible, and aren't sitting atop of things that move around and rearrange themselves a lot.
  • Vastly reduces the risk of damage, not just from vehicle accidents but from all the little rocks and pebbles which get flung up in traffic.
  • Allows you to dispose of and replace buses without losing your investment in the PV panels. The panels will probably last 2-3 decades. Buses on average are replaced after about 12 years.

PV panels on top of buses. Bad idea.

Comment: Re:Van-Bus (Score 1) 94

by Solandri (#46436125) Attached to: California District Launches Country's First All-Electric School Bus

I suspect it would be really hard to build a full-sized EV bus that used less total fuel, considering the transmission and charging losses, and the fuel equivalence for the additional wealth needed to purchase such a thing.

I dunno. Consider how much mass school buses have, I would think you could recoup a huge amount of energy with regenerative braking alone. And unlike cars which only stop at red lights and stop signs, school buses also stop at every pickup/drop (every kid's house in rural areas) and all railroad crossings.

Comment: Re:How efficient is WiFi when crowded? (Score 1) 43

by Solandri (#46426541) Attached to: Stanford Team Tries For Better Wi-Fi In Crowded Buildings

Let's say you live in an apartment building and you can see 16 different SSIDs. Is it slow because there's a lot of data in total being transferred, or does CSMA just collapse (gridlock) so hardly anybody is getting anything?

Unfortunately, the way 802.11b/g were made, they're essentially FDMA. You assign channels to certain frequencies. If two routers happen to use the same frequency, they stomp over each other. (n and ac may do the same thing, I haven't read up on those yet.)

If they'd gone with something like CDMA or OFDMA (orthogonal FDMA), we wouldn't be having this problem. Those two assign orthogonal codes or frequencies to each device. Their transmissions can stomp over each other all day long and the receiver can still tell them apart. Bandwidth scales automatically with number of devices. If you're the only device, you get most of the bandwidth to yourself. If there are lots of other devices transmitting, they essentially increase the noise floor for your signal, and your bandwidth scales down accordingly and automatically. That's the reason these two coding schemes account for the vast majority of 3G and 4G transmission standards on CDMA, GSM (most 3G and 3.5G GSM uses wideband CDMA), and LTE networks.

Incidentally, I ran across a failure mode for CSMA just this weekend. My sister called me over because she couldn't get her TV to connect to her wireless network. It turned out both her router and her neighbor's router were transmitting on the same channel despite their channel selection being in auto mode. The routers were far enough from each other that they weren't picking up each others' transmissions. Her TV however happened to be just about in the middle of the two routers, and was getting a weak but equal strength signal from both. I guess other wifi networks in the neighborhood were causing those two routers to automatically select channel 11.
