Your Computer and Cell Phone Are Lying To You 479
Ant writes with a story from Dan's Data, which says that the battery meter and connection-strength displays in your portable electronics are lying to you, "and not just when they whisper to you in the night." Quoting: "Mobile phones, and most modern laptops, have signal strength and battery life displays. One or both of these displays has probably been the focus of all of your attention at one time or another. Neither display is actually telling you what you think it's telling you. The signal strength bars on a mobile phone or laptop do, at least, say something about how strong the local signal is. But they don't tell you the ratio between that signal and the inevitable, and often very considerable, noise that accompanies it ..."
[Citation-Needed] (Score:5, Insightful)
pedantry (Score:5, Insightful)
Who cares? When it's full, my laptop or cellphone works great. When it's empty, the thing stops working. When there's only a few bars left, I either plug it in / move to a different location. IMO, it perfectly performs its intended duty. Anything beyond that is geek pedantry and nitpicking.
Re:Pshaw (Score:5, Insightful)
And I bet you're going to tell us next that DRM isn't for our own good and is just a way for conglomerates to steal more of our money with little effort done on their part. Hah!
skillful integration of two /. themes
"I already knew that"
"DRM is bad"
Re:pedantry (Score:4, Insightful)
Anything beyond that is geek pedantry and nitpicking.
That is Slashdot.
The balance (Score:4, Insightful)
The engineers dilemma, at least for battery levels:
- how the real value taking into account all variances including current usage and thus constantly move up and down the value
- average out the results to something close, but not exact, since this is what satisfies most people
Fuel gauges also lie (Score:3, Insightful)
yes, yes they do (Score:3, Insightful)
That's funny, because when I have no bars, I can't call out, and when I have all the bars, my calls are great. Likewise, when the battery indicator is full, i can talk for a long time, but when it says it's low, it usually dies soon after that. That's all I need them to tell me. I could care less if it's counting signal strength or magic pixie dust, as long as less pixie dust means the phone is going to die that's fine with me.
Re:Wifi meters (Score:1, Insightful)
At some point, you need to simplify for the users (Score:3, Insightful)
Re:[Citation-Needed] (Score:4, Insightful)
There is no citation needed. I can personally attest to the fact that unless you pay tens of thousands for the equipment it's metering capabilities are ONLY an indicator, more or less like your gas gauge, and not some sensitive sensing system. period. ever.
Most of the work done on electronics in the world is done without exacting measuring equipment. Yes, there will be those that argue, but *MOST* work is done with less than optimal equipment. Think that mechanic working on your car is using micrometers to do everything, or $2500 torque wrenches? For most of the world, good enough is ... well, good enough. Battery monitoring systems can only count down from full charge based on use and time. At best it is a simple calculation that cannot do much to account for aging of the battery or temperature compensation.
No citation needed. That is simply how life is, and why this is a huge 'duh' article, even if joe bloggs doesn't realize it. It's the reason that your vehicle gauges are not calibrated. This applies to just about everything we use.
Re:pedantry (Score:3, Insightful)
I don't know what this "when there's only a few bars left" thing is that you speak of. But then my cell phone can show a full charge for up to 4 days and then be dead less than 4 hours later.
It'd be one thing if the battery use was constant so I'd know that I just need to charge it every 3 days or so... but as it can also randomly decide to discharge itself in well less than 24 hours...
Well, lets just say that I never rely on it when I travel.
Re:[Citation-Needed] (Score:4, Insightful)
Re:Batteries (Score:4, Insightful)
You statement implies that you think it is more useful for the battery meter to display the charge level of the battery rather than the approximate amount of run time left.
For 99.99999999% of the people on Earth (that's everyone other than you), I'm pretty sure that a linear run time indicator is wildly more useful than an actual charge indicator.
Re:yes, yes they do (Score:3, Insightful)
Likewise, when the battery indicator is full, i can talk for a long time, but when it says it's low, it usually dies soon after that. That's all I need them to tell me.
I think the point is that it'd be nice if these things worked in a linear and predictable fashion.
Showing 'full' from 100% to 51% is neither linear nor predictable.
As a developer (Score:4, Insightful)
There isn't standard regarding what reported dBm value should be associated with 1-5 bars. It is purely up to the discretion of the programmer. I have heard RSSI referred to as Relative Signal Strength Indication as well, because the value is at the mercy of internal A/D tolerances. I have seen several copies of the same radios in a lab, (Faraday Cage) report drastically different RSSI values (AKA Bars). Nearby RF sources can influence the signal levels as well.
So that part of the article is true. I dare say anyone who actually knows anything about RF won't claim, bars guarantee connectivity. To say that it is lying to you because you don't understand how it works, makes the submitter look silly. Definition of "Lie" from Wikipedia: "A lie (also called prevarication) is a type of deception in the form of an untruthful statement with the intention to deceive"
We aren't trying to deceive you, we give you the indication because it is better than nothing, and most of the time it is good enough.
Re:Wifi meters (Score:4, Insightful)
[Showing signal to noise ratio] is then overruled by the marketing department because brand 'B' only uses the signal strength, so that makes your product look bad when compared side-by-side, since theirs has more signal bars.
Then show the signal in solid black bars and the noise in staticky bars. Suggest that the marketing department include something to this effect in the ad copy: "Sure you get a lot of bars, but are they good bars?"
Re:Easier for sales (Score:3, Insightful)
Taking the article to heart, maybe the reason they have more bars in more places is because they start at 3 bars for no signal and go all the way up to 4 bars for full signal.
Re:Ummm, doesn't "lying" imply free will? (Score:5, Insightful)
It's simply Anthropomorphism [wikipedia.org]. I talk to my car when it runs bad. I don't expect it to hear me or comprehend, but I do anyway. I talk to the computer, too.
When I talk to machines, for some reason it's always cursing, as in "GOD DAMNED PIECE OF SHIT..."
Re:Fuel gauges also lie (Score:3, Insightful)
Re:Easier for sales (Score:3, Insightful)
Hey now - they said NOTHING about signal strength or SNR. Just "more bars". If (bars > 0) then bars++
Re:Wifi meters (Score:5, Insightful)
Not in the least because many common wifi chipsets don't make raw signal strength available to the rest of the system. Cellular modules do, but if you ask a phone maker how the number of bars corresponds to the error rate and signal strength, they won't tell you. Although a bit of experimentation reveals that as long as the error rate is low and the signal is above the noise floor, you get full bars. That's probably marketing.
The battery conspiracy thing is a bit silly. Rechargable battery chemistry follows an S-curve. There's a very short period at the beginning with the battery over the nominal voltage, a long and almost linear middle section, and a short period at the end where the voltage drops quickly. So a naive voltage measurement gives exactly as described in the article -- almost full most of the time with a quick drop at the end. A less naive measurement is very tricky because the voltage in the linear section depends not only on state of charge, but current draw, recent current draw, temperature, the age of the battery being used, etc. The best way to do it accurately is to track a particular battery through its charge cycle and monitor current in and current out. Smart batteries like those in laptops do. I don't think cell phone batteries are smart batteries.
What A Pointless Article (Score:4, Insightful)
Slow news day, apparently.
Re:[Citation-Needed] (Score:3, Insightful)
Re:Pshaw (Score:1, Insightful)
I drive an SUV for one reason, and one reason only:
F = ma
I drive a 2 ton car. I live in the Midwest, where many other people do too. I am attempting to ensure (to a reasonable extent- I don't drive a semi) that I will either be bigger, or almost as big, as any car I will be in an accident with.
Is it a perfect plan? No. But it has worked so far.
-Sandbenders
Re:Pshaw (Score:5, Insightful)
Or you could try to not get into an accident. The best way to do that is to drive a small, agile car and watch where you're going (I can tell you it really works wonders! Even just watching where you're going and minding the objects around you makes a huge difference!). But why go through all that trouble? It's better to get the biggest cudgel of a vehicle that's practical and let physics sort 'em out!*
*hint: your safety is not determined solely by the G-forces you experience in an accident.
signal strength .. blame it on IEEE (Score:2, Insightful)
Re:Ummm, doesn't "lying" imply free will? (Score:3, Insightful)
In college, I had a 486/66 with "personality". I named her ("Talena" for you Gor fans out there), and talked with her. I got occasional strange looks, but nothing ever was harmed. She would periodically stop booting and I'd need to reseat all her cards and memory. You see, the dorm was a very dusty place and the temperatures were not that well regulated, and she was pretty cheaply made -- I couldn't afford much. I knew full well the physics of thermal cycles and the electrical properties that our dust had, but my math major roommate's eyes glossed over with that stuff until I said, "She's a girl, she needs me to pay attention to her once in a while". He understood my meaning, and appreciated the distilling of "the truth" into "easy to understand". She had a few other quirks that were related to the fact that no two components came from the same vendor, and that all were found in the back of my 15 pound Computer Shopper, and those piled up into choosing her name.
Anthropomorphism isn't about thinking things are really like people, it's about approximating real truths into things that allow our social brains to remember and interact with.
Except it's built in (Score:3, Insightful)
Except it's still a trait of the brain, and it's not even just a human trait.
E.g., your dog is treating you as a bigger and stronger dog, and essentially only follows you because you're the alpha dog. Males around the age of 2 even get ideas about challenging you for who's going to be alpha. And apparently don't bother wondering what _would_ they do if thee roles were really reversed, with you as the pet and him as the master (really, alpha.) But essentially he sees you as a dog, and expects that you'd follow the dog rules there.
E.g., your cat almost invariably just accepts you as the alpha cat of the colony, and unlike dogs it's even realistic enough to not challenge someone 10 times its weight to a fight for alpha status. Mind you, alpha status in a cat colony doesn't actually mean they have to follow or obey. It just gives you dibs on food and the right to bully your underlings a bit, but not too much. If it's an apartment cat, well, it's your food in the first place, so having dibs on it doesn't really do anything. But anyway, there are plenty of signs that you're largely simplified to a big cat in a lot of aspects.
I'd call it anthropomorphising, but that's actually the wrong word there, because of the "anthropos"="human" root. You're just mentally assimilated to one of their own.
Mind you, both seem to realize you're not 100% a dog or a cat, but then humans anthropomorphising animals doesn't go to 100% either.
Both cats and dogs seem to basically treat inanimate objects as, at the very least, living. You can see it in, say, dogs instinct to chase off cars, or occasionally doing stuff like barking menacingly at some object which hurt them in some way.
So basically you can get all snotty and derisive about it, or you could realize that (A) that's how we're wired, as mammals, and spend less time pretending you're something else than human, and (B) it doesn't matter anyway, since none of us are that stupid as to really believe the computer is human or even alive. We might cuss at it or use some fucked-up metaphor like "my computer hates me", but, here's the important part, none of us actually takes either literally. We don't expect the computer to react to that cussing, nor to have its crashes really influenced more by "hate" than by its drivers.
So it's no more retarded than any other metaphor. We also talk about stuff like:
- the crack of dawn (yes, we _know_ that nothing actually gets cracked there)
- taking the piss, getting pissed, or pissing against the wind (no actual urine is involved in either)
- jumping the shark (no actual fish involved)
- burning one's bridges (it doesn't literally involve a bridge and fire)
Etc, etc, etc.
So unless you're against any non-literal kind of speech as a whole, I fail to see while you'd single out anthropomorphism. Again, trust me, nobody takes it any more literally than they take the above expressions. So what is the problem, really?
Re:Pshaw (Score:3, Insightful)
Its true that, from the statistics, you are, per accident, less likely to be injured in an SUV. The social downside is that the person in the other car is more likely to be injured in accident if you're in an SUV, but that's their problem. The personal downside is that you're more likely to be in an accident if you are in an SUV, and that the greater likelihood of an accident negates any advantage from the lower probability of injury. Essentially, from a safety perspective, what an SUV buys you is a greater chance of injury someone else.
Likewise, the magic talisman I wear to ward off bullets has worked so far; as long as I've had it, I haven't been shot.
Re:Pshaw (Score:4, Insightful)
Or that the panels for your Trailblazer are cheaper than for the Cavalier. Repair costs have as much to do with insurance costs as the likelihood of an accident.
Comment removed (Score:3, Insightful)
Re:Pshaw (Score:5, Insightful)
I live in the snowbelt.
I've seen a lot of 4-wheel drive SUVs/trucks in the ditches, because they displace overconfidence (like you just did). Meanwhile I've driven a midsize or compact car, and have never had an accident in the snow. The key? "Don't drive faster than 30 miles an hour ya dope!"*
As for F=ma, there's also "energy absorbing crush zones" to consider. A crash-friendly chassis is more important than F=ma. i.e. A 5000 pound SUV that remains solid like a brick (but turns its occupants into scrambled eggs) is a lot more dangerous than a 2000 pound civic that crumples like a wad of paper (but protects its passengers from damage). What matters is how well the vehicle ABSORBS the energy, not its weight. Also worthy of note: SUVs are more dangerous than cars. Why? SUVs rollover and smash the occupants.
* (By dope, I'm referring to those numerous persons I see driving 65 on the interstate during snowstorms... I always wonder how they think they're going to stop while driving on slush.)
Re:Pshaw (Score:3, Insightful)
Dude, get a Subaru and some snow tires. They're the national car of the Republic of Vermont.
Re:[Citation-Needed] (Score:5, Insightful)
Every car I've ever owned has worked the same way. The bar will remain on "F" until 60% is reached, and then it gradually starts dropping. When the gauge claims I have "1/4" I really only have 15% of my fuel tank left.
I've heard stories of car companies trying to make more accurate gauges, but the customers complained that the car was "half empty" after "only" 150 miles. They prefered the old gauges that still showed almost-full, even though those gauges were lying.
So I suspect the real conspiracy is just "the ignorance of the average citizen" that led to deceptive gasoline and battery meters.
Re:Pshaw (Score:2, Insightful)
Let's see, did I say anything about the handling of a larger vehicle?
Hmm, nope I didn't.
What I insinuated is that relying on the agility of a car to always evade a collision instead of driving a vehicle capable of withstanding an impact is folly due to agility not always being able to be applied. A vehicle's structure is a passive defense. Agility is an active defense.
And yes, those SUVs end up in the ditch because they believe 4WD lets them drive on anything in any manner they want.
You can control your driving, but you can't control the behavior of other drivers. Get a localized patch of ice in one lane and you can get an out of control vehicle headed off into another lane. The driver in that lane now has to deal with that large object on a collision course with him.
I'd prefer to be in a vehicle that can absorb and safely distribute more energy than a pop can can. All these "big cars are evil!" "drive a tin can on wheels, it's more agile and it saves the world!" types rarely take actual conditions into consideration.
Classic slashdot idiocy.. (Score:1, Insightful)
This piece assumes that a 5-bar display should accurately drop in 20% chunks. Why is this?
Only a geek would expect bars to mathematically co-relate with percentage charge, or signal. All other humans would expect something far more complicated.
Folks, this is a MAN-machine interface (Human-Computer interface for the tree-huggers amongst us). That means you have to consider HUMAN responses.
And human responses don't generally match precisely to 'amount used' for anything. The way they go is "there's enough...there's enough...there's enough...whoops, it's getting low - better cut back..."
Where the Whoops comes is variable, but so long as you've got 50% of anything left, you're usually OK. 25% left, you start worrying. 5% left, you look for a fill-up.
That's what the bar code tells us. Myself, I can't see that it's a problem. Except for geeks, but who ever considered them? Besides, they can look after themselves...
Re:Pshaw (Score:3, Insightful)
I take it you've never seen two cars sliding towards each other on glare ice with nothing the drivers can do about it.
No, but I DO think that there's something to do with how every winter I see ~10 SUVs in the ditch for every car, when the actual proportion is about 50-50. Hardly see any trucks in the ditch, but they aren't everywhere on the road either.
Hint: 4 wheel drive vehicles don't brake any better than a 2 wheel drive one. A front wheel drive car will stop just as quickly in limited traction conditions as a SUV, assuming similar tires and speed. A car with studs will stop far more quickly than a SUV with all-seasons.
You'd have a better arguement about getting stuck in the snow is more likely for a small agile car compared to a 4WD SUV.
Re:Pshaw (Score:1, Insightful)
'Rally is done in small, agile cars, not in SUV's'
But in combat, it's the reverse!
Re:Pshaw (Score:2, Insightful)
It doesn't matter. (Score:3, Insightful)
Your phone isn't telling you either the strength of your signal or the SNR.
It's telling you which level of transmit power it is using.
If your phone can show n bars, it has n+1 transmit power levels. Subtract the number of bars it shows from n+1 and you will know the integer value that is in its transmit-power variable. If you see 0 bars, your transmit power is cranked up to 4, for example.
Why does it vary the transmit power? Sometimes it's because the tower is measuring the power that it sees from your phone, and sends back an increase-power or decrease-power code in one of the messages they are exchanging. Your phone can't measure these things (waste of space and power). The tower doesn't want you blasting other phones off their links, either. If your phone can't see a signal it will simply go to full power and broadcasts connection requests (this is why your phone dies quickly when you go roaming).
If the tower can't see you any more, it just doesn't say anything. If you can't see the tower, you start transmitting at full power. "Can't see you" includes rejecting packets that are corrupted by noise. So if there is a enough noise to make the signal unrecoverable, regardless of the real signal strength, your phone will be trying to get through by going to full power.
The fact that some phones continue to send balky noises to your earpiece is a feature. It is giving you what it has rather than resetting the connection.
And the noise that causes those balky noises in your earpiece may not be radio noise in your area. They could be radio noise at the other end, or errors in any part of the transmission chain between your tower and the other end. There will never be a way to measure the end-to-end bit-error-rate in a cell phone. No point telling you in a number what you can already hear.
Re:Pshaw (Score:2, Insightful)
the person in the other car is more likely to be injured in accident if you're in an SUV, but that's their problem.
If you go the dictionary and look up the word "selfishness" that's the definition you'll find. Playing the game of buying the most massive vehicle in order to deflect injuries onto other people is nothing but pure selfishness. Everyone would be a lot safer if everybody refused to play that game.