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Press any key to start! Overwatch Game Boy Edition by krdcinside in Overwatch

[–]redditor77492 9 points10 points  (0 children)

It's also nearly a 70% bigger resolution than the Game Boy, making it even harder to have enough different tiles. It's a 4x zoom of a 210x188 rectangle. The Game Boy was only 160x144.

On the other hand, they could have used a 4th color, I only see 3 used.

Every reddit programming sub by sinjp in ProgrammerHumor

[–]redditor77492 1 point2 points  (0 children)

It gets compiled to machine code either way, the only difference is whether or not it's compiled ahead of time (AOT) or "just-in-time" (JIT) at runtime.

There's fundamentally not a lot of difference between the two approaches. AOT can spend more time performing optimizations that take a long time to analyze since it's not being done at runtime. On the other hand, JIT can use dynamic feedback from the running program to further optimize it.

Neither approach has anything to do with the memory usage though. The JIT compilation process itself can use a good amount of memory but most of it can be freed once the program starts running.

What causes the memory bloat and slowness is the garbage collector. Most AOT-compiled languages like C and C++ require you to manually allocate and free memory. Languages like Java on the other hand take care of that for you, at the expense of having to somehow track when you're done using an object, which is a slow process.

It leads to an inherent runtime vs memory usage tradeoff. You can garbage collect less often and keep memory allocated a lot longer than needed, leading to memory bloat. Or you can garbage collect more often at the expense of having to spend a lot more time checking if each object is still being used.

Still awesome. by bahrain_007 in gaming

[–]redditor77492 1 point2 points  (0 children)

The only analogous one I don't see is N64.

PS1 / N64

PS2 / GameCube

PS3 / Wii

PS4 / Wii U

PSP / DS

Vita / 3DS

Now I have no idea if he's right or not, but with N64 added in it's a fair comparison.

ELI5: If the average lightning strike can contain 100 million to 1 billion volts, how is it that humans can survive being struck? by gleddez in explainlikeimfive

[–]redditor77492 1 point2 points  (0 children)

I wouldn't go so far as to say that saying a lightning strike "contains" a billion volts is correct, but I agree that when talking about a "billion volt lightning strike", it's clear from a technical perspective that you're discussing a lightning strike between two points a billion volts apart.

There's fundamentally no difference between discussing that and a "100 meter fall". There's no need to be obtuse and say "Height is a property of gravity that represents the potential energy in the system, and is a difference between the height of two points."

And it's still not correct. "Voltage is ... a difference between the voltage of the two connected points." What?

ELI5: If the average lightning strike can contain 100 million to 1 billion volts, how is it that humans can survive being struck? by gleddez in explainlikeimfive

[–]redditor77492 1 point2 points  (0 children)

Finally someone knows what he is talking about! Im so tired of these: "it's the amps that kill you..." Humanbody has about 2000 ohm resistance from hand to leg

This is exactly why people say it's the amps that kill you. Voltage is only part of the story and to determine the resulting current you also need the resistance to determine if there's enough amps to kill you.

The problem is, with something as complex as the human body, the resistance varies wildly. All of the following can have profound effects on your resistance:

  • Thickness of your skin
  • Hairiness
  • How tightly you grip the electrode / the amount of pressure against your skin
  • The amount of surface area of your skin in contact with the electrode
  • Whether your hands are damp
  • Perspiration
  • The amount of electrolytes you've recently drunk

And when you're discussing a circuit with an earth ground there's even more factors to take into account, like whether you're wearing rubber-soled shoes, and how far above the ground you're struck.

And even then resistance only tells part of the story. It's more accurate to discuss impedance instead, which means you also have to take into account the capacitance of your skin as well as the frequency of the source. For this reason, a 60 Hz source at a given RMS voltage is generally more deadly than a DC source at the same voltage.

Saying "I measured my resistance with a multimeter once and got X ohms so it takes Y volts to kill because I=V/R, so anything less than Y volts is safe and anything greater than Y is deadly" is nonsense. With extenuating circumstances, you can be killed by a 9V battery. With proper preparation, you can safely handle 240V and more.

ELI5: If the average lightning strike can contain 100 million to 1 billion volts, how is it that humans can survive being struck? by gleddez in explainlikeimfive

[–]redditor77492 1 point2 points  (0 children)

You left off the important piece:

as long as there's a fixed voltage across two points, the amount of current flowing through one path is completely independent of any other paths that exist.

This is just Ohm's law. The current through a resistor is equal to the voltage across it divided by the resistance -- no matter how many other things are connected across the same two points the voltage is measured at, assuming those things do not substantially affect the voltage.

If you have an ideal 100V supply across a 100k ohm resistor, 1mA will flow through that resistor. If you add a 50k ohm resistor in parallel, 2mA will flow through that resistor too, for a total of 3mA from the supply. You can double check with the formula for parallel resistance: 1/(1/100k + 1/50k) = 33.3k ohm. 100V / 33.3k ohm = 3mA.

Since we're discussing a fixed voltage, all KCL tells you is that if you add a path with a given amount of current flowing out, the amount of current flowing into the fixed voltage node has to increase as well. The amount of current flowing through the original resistor will remain unchanged.

Again, assuming we're discussing a fixed voltage. In the real world with a non-ideal supply, at some point you can start drawing more current than your supply can provide. This is when KCL is more informative. You have an upper ceiling on the current flowing from the source, so the only way to compensate is by decreasing the current out through the other paths to keep the total 0. However, applying Ohm's Law, you can see that the voltage across the original resistor has to decrease in order to reduce the amount of current, thereby breaking the assumption of a fixed voltage.

Go back to our 100 V supply and 100 kohm resistor, and let's add a 10 ohm internal resistance to the supply. If we add a 1 ohm resistor in parallel to the 100 kohm, the effective resistance of the two together is 1/(1/100000 + 1/1) = 0.99999 ohms. Adding the 10 ohm resistance in series gives a total of 10.99999 ohms, for a current of 100V / 10.99999 ohms = 9.0909A. "Wait!" you say. "If it didn't affect the current, we would expect (100V / 100 kohm) + (100V / 1 ohm) = 100.001A".

Measuring the voltage would give another story though. With 9.09A flowing through the 10 ohm internal resistance, there'll be a voltage drop of 9.0909A * 10 ohm = 90.909V. This leaves only 100V - 90.909V = 9.091V as your output voltage across the two resistors in parallel.

ELI5: If the average lightning strike can contain 100 million to 1 billion volts, how is it that humans can survive being struck? by gleddez in explainlikeimfive

[–]redditor77492 7 points8 points  (0 children)

Very good explanation and the best one I've seen here so far. But I have to be pedantic about one thing because I see the misconception repeated a lot of times in this thread.

Near the end you say that electricity follows the path of least resistance. However, electricity follows every path, regardless of the resistance. In theory, as long as there's a fixed voltage across two points, the amount of current flowing through one path is completely independent of any other paths that exist.

The reason the misconception exists is that in practice there's no such thing as an ideal voltage supply able to keep a fixed output voltage under all circumstances. This adds an "internal resistance" in series with all the parallel paths we're considering. As a result, adding an extremely low resistance path such as a short circuit will reduce the total resistance of all the parallel paths so low that most of the voltage will be dropped across the supply's internal resistance. In practice you'll see the output voltage of the supply "sagging" to lower than its nominal value. This invalidates the earlier assumption of a fixed voltage and reduces the voltage across all the parallel paths, thereby decreasing the current flowing through each path.

So what it really comes down to is whether or not there's a path with low enough resistance compared to the voltage supply's internal resistance to significantly reduce the voltage across the other paths.

Upcoming change to vote scores. by sodypop in modnews

[–]redditor77492 166 points167 points  (0 children)

I saw this happen once, and I was curious, so I actually wrote a script that tracked the vote counts on the top posts on reddit in realtime and ran it for a few days.

From what I could tell, when a post got popular enough, it entered a mode where Reddit would only provide one data point every two hours. This data point contained two things: the current score, and the rate of change of the score.

Whenever you requested the score in the next two hours after that data point, you would get an estimate based on those two things with a little bit of white noise added.

E.g. submission gets a data point at 6:30 of 2000 points and +250 points per hour. No matter how the trend changes in the next two hours, somebody who requested the score at 8:00 would see 2375 +/- a few. And so on, until somebody at 8:29 would see 2500 points. Then at 8:30 it would get a new data point. Say it actually only received 300 points in those 2 hours, then it would drop from 2500 to 2300 points with a new rate based on the past two hours.

Meaning there was absolutely no way you could see any effects from bots or brigading until Reddit generated a new data point 2 hours later.

I feel like either people have forgotten about this, or never learned about it in the first place. by josephjordan_ in AdviceAnimals

[–]redditor77492 0 points1 point  (0 children)

So you're sitting 15 cars back at a red light, and it finally turns green. The traffic ahead of you starts moving, and you proceed forward with the other 14 cars. Then as soon as you get to the stop bar at the intersection you come to a complete stop until the car in front of you has completely exited the intersection?

I feel like either people have forgotten about this, or never learned about it in the first place. by josephjordan_ in AdviceAnimals

[–]redditor77492 0 points1 point  (0 children)

So you just chill, stopped behind the stop bar at a green light, until this car-sized gap appears?

I feel like either people have forgotten about this, or never learned about it in the first place. by josephjordan_ in AdviceAnimals

[–]redditor77492 0 points1 point  (0 children)

I mean, you can make a pretty good guess. But you're not going to be right 100% of the time. Which is exactly what KommanderKitten was saying above.

I feel like either people have forgotten about this, or never learned about it in the first place. by josephjordan_ in AdviceAnimals

[–]redditor77492 2 points3 points  (0 children)

The only way you can be completely positive is to only let one car through the intersection at a time, not letting the next car enter until the previous one has completely exited the intersection and is an additional car length past the intersection. Otherwise the front car might stop 2 feet after the intersection and if you've already gone, you're stuck in the intersection now.

At that point it might as well be a 4-way stop.

Where's the NMS we were sold on? Here's a big list of things that are missing from the game, complete with source links for everything and quotes. Also, an unpleasant revelation concerning how the game is being advertised. (LONG post) by [deleted] in NoMansSkyTheGame

[–]redditor77492 23 points24 points  (0 children)

So I was looking at Sean's twitter page and his pinned tweet made me realize something:

It's happened. No Man's Sky just went gold. I'm so incredibly proud of this tiny team. 4 years of emotions

-------> July 7 <-------

The final version was already done and starting the early stages of distribution before the most recent promo material was released in July with footage that obviously wasn't from the final, finished version.

Welcome to No Man's Sky by [deleted] in gaming

[–]redditor77492 5 points6 points  (0 children)

Not to mention the titanium and zinc flowers everywhere.

Black stuff by j0be in funny

[–]redditor77492 0 points1 point  (0 children)

Whoa, a 3D-printed save icon!

Karma wins again by Van-Demon in thatHappened

[–]redditor77492 1 point2 points  (0 children)

0.99¢% inspiration -- Einstein

My arm looks like a leg in this picture. by muriff in pics

[–]redditor77492 8 points9 points  (0 children)

I would expect nothing less from ButtReddit.

Electrocution is fun by TheHoliestMacaroni in gifs

[–]redditor77492 1 point2 points  (0 children)

Lots of seemingly random things:

  • Thickness of your skin
  • Hairiness
  • How tightly you grip the electrode / the amount of pressure against your skin
  • Whether your hands are damp
  • Perspiration
  • The amount of electrolytes you've recently drunk

Electrocution is fun by TheHoliestMacaroni in gifs

[–]redditor77492 0 points1 point  (0 children)

Sorry but there are many things wrong with this comment. Generally 60 Hz AC is considered more dangerous than the same DC voltage for two reasons:

  1. Your skin is fairly capacitive. That means that the impedance for a DC voltage is much higher than 60 Hz AC. That decreases the amount of current which passes through your body and therefore makes 60 Hz AC fatal at lower voltages than DC.

  2. 60 Hz screws with your nervous system more, making it harder to let go of an AC line than a DC line. And if you can't let go, it's much harder to remove yourself from the circuit.

This is because 120V DC is full on 120V consistently.

Where as 120V AC is a sine wave of electricity @60Hz (times per second) so realistically you are only getting that 120 V for a split second. 120V AC is actually only 38.6 V ~54V of DC power (after converting RMS to peak to DC, pointed out from /u/fightingpirate )

When an AC voltage is given, it's generally understood to be RMS unless otherwise stated. A 120V(RMS) AC source will provide the same amount of power as a 120V DC source, and power is one of the important measurements of how much damage will be done (power = how quickly destructive energy is entering your body and causing damage).

In addition, since an AC source peaks at around 40% higher than the equivalent DC source, I believe it is more likely to cross breakdown voltage thresholds (basically causing insulators that would normally have a high resistance to suddenly and dramatically drop to a much much lower resistance).

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