Clearly you will run into SSD erase-limit problems at such a rate, but such workloads normally turn out to not be tasks that actually benefit from an SSD to begin with (32.8GB/day = 380KB/sec, so the devices speed wasnt actually an issue for you)
Actually, most devices will survive several years at such a rate. GP was unlucky to see failures quite
Except if you actually bothered to educate yourself, you'd find that at the capacities samsung is offering you, if you write to them at 10GB a day, every day, they'll last entirely respectable times (12,23,47,94 years respectively for 120,240,480 and 960GB drives).
The problem with such tests of writing as much as you can as fast as you can is that they're rather deceptive. They don't allow TRIM and wear levelling to do their thing (as they normally would), and hence show a much worse scenario than you would normally be dealing with. Actual projections of real life usage patterns writing ~10GB to these drives per day show you can get their life span in years (specifically the 840 we're talking about here) by dividing the capacity (in gigabytes) by 10.
The problem with large scale studies on this is that it takes too long to happen to actually study. You need to study real world usage patterns, and in the real world it takes decades before the flash actually wears to death. Controller failure (as is possible with HDDs too) will generally happen long before the flash becomes unwritable.
Yes, many sites have done the maths on such things. The conclusion "finite life" is not the same thing as "short life". SSDs will in general, outlast HDDs, and will in general die of controller failure (something which affects HDDs too), not flash lifespan.
The numbers for the 840 (which uses the same flash, with the same life span) showed that for the 120GB drive, writing 10GB per day, you would take nearly 12 years to cause the flash to fail. For the 240/480/960 options for the new version you're looking at roughly 23, 47 and 94 years respectively. Given that the average HDD dies after only 4 years (yes yes yes, we all know you have a 20 year old disk that still works, that's a nice anecdote), that's rather bloody good.
Our taxes go on that kind of thing because without funding it, the scientists will leave to other countries, and in 5 years time this is what you will have:
An economy trying to recover, just about
No researchers with cool ideas for how to spend the money you now have on projects that could run the economy for the next while No graduates from uni worth anything because they've had no one worth anything teaching them anything.
Basically, because the people who are running the country have some foresight, and realise that we need to spend money to make money. Unlike you, you idiot.
So you have to get up 2/3 of a mile in 20 miles, that's a gradient of 1 in 30, aka a 2 turn. An arc around a 10 mile radius turn (larger than you need), turning 2 is 0.3 miles long, so no, that's not a significant obstacle at all.
Did you ever notice that roller coasters are designed with the express intent of making people uncomfortable in order to get their heart beating faster, and adrenaline deposited into them?
the thing is in a round tube, the centre of mass of the car is below the centre of the tube, it will always rotate such that the centre of mass is pushed to the lowest energy point, so a passenger would only feel vertical G, like sitting in a fast vertical elevator. 2G is a very tame roller coaster, or a fairly brutal elevator. You would certainly feel it, but it wouldn't be that uncomfortable, especially in those fully supportive seats.
Actually, vertical acceleration is the worst possible scenario for a human. Longitudinal acceleration is the best case (hence why people being launched into space lie down in the capsule). Lateral acceleration is somewhere in between. Rollercoasters rarely come close to pulling even 1G of acceleration (which they do only to give you a moment of weightlessness). Even the most brutal of lifts only pull around 0.2G at most. Clearly a 2G accelerating lift would not be a good plan, as you're then talking about pinning the passengers to the roof with the same force as they're normally stuck to the floor.
You'd say wrong. Most humans never encounter 2g turns in their life time. Your car will turn at a fraction of a g. The only time that most humans might get close to 2g is driving around a go-cart track, and most inexperienced drivers will get neck ache from it because their muscles aren't used to standing up to that kind of force.
In general, you need to stay below half a g for the general population to be comfortable.
But, as we've covered in the rest of this thread, that's not really a difficult thing to do.
True, but that's much easier than buying the land outright, when you're gonna cut some farmer off from most of his field, and make him drive 10 miles each way to get round to it.
To be fair, humans are quite capable of withstanding 7.7G – just only laterally and longitudinally. Vertically it's a problem.
Laterally our limit is around 30G. Formula 1 drivers happily pull 6-7G turning with no need for a G-suit. Longitudinally we have no known limit before we turn into a pulp like substance.
Why would you go anywhere near Santa Clara? The proposal is to go up the I5. And no one claimed there would be no deviation from the freeway, just only minor deviation. If you'd actually read the documentation you'd also see that where you do deviate the issue is far less of an issue than for a conventional railway, because being mid-air, the farmer only has to put up with a few pylons being placed in his field, rather than a 30m wide swath that he can't cross. The bottom line is that it is substantially easier to get this across the country, and requires substantially less land purchasing. Where it does involve land purchasing, it's much easier to convince the owners that it's okay, due to not cutting their land in half, and not taking a large section of it; and it's substantially cheaper because you only need to buy the land to site the pylon bases.
Generally, it's a win all round compared to railways.
The third dimension is trivial to avoid tight turns in, and even zooming in on the map reveals no significant tight turns that can't be straightened simply by dodging from one side of the road to the other.
A quick look at the freeways between LA and SF shows that they are mostly straight, with only very minor turns occasionally. A quick look shows that there's only two places where the route curves more tightly than the 14km radius turn required to keep under 1g acceleration at 800mph. Both of these locations are close to the end points, where the thing would still be under acceleration anyway, and if you really wanted to run at 800mph through them, there are 14km radius turns available in the area.
Q: How do you elevate? A: you place them under ground
Wrong, this is one of the key features here – it's overground, so that it doesn't involve expensive tunnelling, and can have solar cells on top of it to power the thing.
Q: G-Forces A: www.wikipedia.org calculate how big a circle must be, to put only 2-3 G-s on the body, it's not that big.. r=500m or so
Bear in mind that most humans never experience even 2g acceleration. About the most likely place they are to experience 2g is at a go-kart track, and for most, 45 minutes of that will give them neck ache because their neck muscles are not used to supporting their head under that load. You'd need to keep cornering forces to under 0.5-1g, but even that requires 14km radius turns.
It does run along freeways. You're making a false assumption that because something wasn't designed to carry things at 800mph, it can't carry them at that speed. the vast majority of the freeways are dead straight, or involve only very gentle curves. The small areas where the curves are too tight can be shortcut across, which will indeed require a small amount of land grab, but this is being proposed as an alternative to a rail link that would involve a land grab along its entire length, so that's already a vastly simplified problem.
It doesn't matter if they were designed for it or not. They happen to be straight enough anyway, bar a very few locations. This simplifies the land grab issue thousands of fold. Given that this is being proposed as an alternative for a rail link that requires a land grab along its entire route, that's a massively simplified problem.
Land is going to be what kills this project, before it even gets as far as anything technical. How do you acquire the land for the route as a private entity, without eminent domain?
If you had even read the basic media coverage of this, you would know that he is proposing mounting this over the central reservation on freeways, so no land purchasing would be necessary.
Sheesh, it's an argument, some points are insightful, others are a little over the top and baitish. But why can't people just let each other discuss why they have differing opinions and attempt to enlighten themselves?
It's actually kinda amusing to see this argued. The entire basis for the GPL is "people who use and extend my code can't distribute under their own terms –they are restricted to doing something that's good for users instead. If you don't like that, don't use my source".
To see it argued that those people were morally consistent to say "no, take it down from the app store, developers' rights are more important than users' ones" is pretty funny.
Right, that's not because these users are not aware that there's a threat of getting some kind of malware on their machine. This is because the problems caused by the antivirus software are as bad as the problems caused by a virus, so basically, you're asking them to guarantee that they have something malicious on their system, rather than simply having a 1 in a million chance that they do.
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Clearly you will run into SSD erase-limit problems at such a rate, but such workloads normally turn out to not be tasks that actually benefit from an SSD to begin with (32.8GB/day = 380KB/sec, so the devices speed wasnt actually an issue for you)
Actually, most devices will survive several years at such a rate. GP was unlucky to see failures quite
Except if you actually bothered to educate yourself, you'd find that at the capacities samsung is offering you, if you write to them at 10GB a day, every day, they'll last entirely respectable times (12,23,47,94 years respectively for 120,240,480 and 960GB drives).
Yes, the 840 did indeed suffer from this, but as I said up the thread, the firmware was patched to fix the issue.
Noting that march is a long time ago in tech terms, and that one of the (incredibly small sample of 2) HDDs suffered issues as well.
The problem with such tests of writing as much as you can as fast as you can is that they're rather deceptive. They don't allow TRIM and wear levelling to do their thing (as they normally would), and hence show a much worse scenario than you would normally be dealing with. Actual projections of real life usage patterns writing ~10GB to these drives per day show you can get their life span in years (specifically the 840 we're talking about here) by dividing the capacity (in gigabytes) by 10.
Yes, they were solved in a firmware patch a long time ago.
The problem with large scale studies on this is that it takes too long to happen to actually study. You need to study real world usage patterns, and in the real world it takes decades before the flash actually wears to death. Controller failure (as is possible with HDDs too) will generally happen long before the flash becomes unwritable.
Yes, many sites have done the maths on such things. The conclusion "finite life" is not the same thing as "short life". SSDs will in general, outlast HDDs, and will in general die of controller failure (something which affects HDDs too), not flash lifespan.
The numbers for the 840 (which uses the same flash, with the same life span) showed that for the 120GB drive, writing 10GB per day, you would take nearly 12 years to cause the flash to fail. For the 240/480/960 options for the new version you're looking at roughly 23, 47 and 94 years respectively. Given that the average HDD dies after only 4 years (yes yes yes, we all know you have a 20 year old disk that still works, that's a nice anecdote), that's rather bloody good.
Our taxes go on that kind of thing because without funding it, the scientists will leave to other countries, and in 5 years time this is what you will have:
An economy trying to recover, just about
No researchers with cool ideas for how to spend the money you now have on projects that could run the economy for the next while
No graduates from uni worth anything because they've had no one worth anything teaching them anything.
Basically, because the people who are running the country have some foresight, and realise that we need to spend money to make money. Unlike you, you idiot.
So you have to get up 2/3 of a mile in 20 miles, that's a gradient of 1 in 30, aka a 2 turn. An arc around a 10 mile radius turn (larger than you need), turning 2 is 0.3 miles long, so no, that's not a significant obstacle at all.
Did you ever notice that roller coasters are designed with the express intent of making people uncomfortable in order to get their heart beating faster, and adrenaline deposited into them?
This is not something you want on public transit.
the thing is in a round tube, the centre of mass of the car is below the centre of the tube, it will always rotate such that the centre of mass is pushed to the lowest energy point, so a passenger would only feel vertical G, like sitting in a fast vertical elevator. 2G is a very tame roller coaster, or a fairly brutal elevator. You would certainly feel it, but it wouldn't be that uncomfortable, especially in those fully supportive seats.
Actually, vertical acceleration is the worst possible scenario for a human. Longitudinal acceleration is the best case (hence why people being launched into space lie down in the capsule). Lateral acceleration is somewhere in between. Rollercoasters rarely come close to pulling even 1G of acceleration (which they do only to give you a moment of weightlessness). Even the most brutal of lifts only pull around 0.2G at most. Clearly a 2G accelerating lift would not be a good plan, as you're then talking about pinning the passengers to the roof with the same force as they're normally stuck to the floor.
You'd say wrong. Most humans never encounter 2g turns in their life time. Your car will turn at a fraction of a g. The only time that most humans might get close to 2g is driving around a go-cart track, and most inexperienced drivers will get neck ache from it because their muscles aren't used to standing up to that kind of force.
In general, you need to stay below half a g for the general population to be comfortable.
But, as we've covered in the rest of this thread, that's not really a difficult thing to do.
True, but that's much easier than buying the land outright, when you're gonna cut some farmer off from most of his field, and make him drive 10 miles each way to get round to it.
To be fair, humans are quite capable of withstanding 7.7G – just only laterally and longitudinally. Vertically it's a problem.
Laterally our limit is around 30G. Formula 1 drivers happily pull 6-7G turning with no need for a G-suit.
Longitudinally we have no known limit before we turn into a pulp like substance.
Why would you go anywhere near Santa Clara? The proposal is to go up the I5. And no one claimed there would be no deviation from the freeway, just only minor deviation. If you'd actually read the documentation you'd also see that where you do deviate the issue is far less of an issue than for a conventional railway, because being mid-air, the farmer only has to put up with a few pylons being placed in his field, rather than a 30m wide swath that he can't cross. The bottom line is that it is substantially easier to get this across the country, and requires substantially less land purchasing. Where it does involve land purchasing, it's much easier to convince the owners that it's okay, due to not cutting their land in half, and not taking a large section of it; and it's substantially cheaper because you only need to buy the land to site the pylon bases.
Generally, it's a win all round compared to railways.
The third dimension is trivial to avoid tight turns in, and even zooming in on the map reveals no significant tight turns that can't be straightened simply by dodging from one side of the road to the other.
A quick look at the freeways between LA and SF shows that they are mostly straight, with only very minor turns occasionally. A quick look shows that there's only two places where the route curves more tightly than the 14km radius turn required to keep under 1g acceleration at 800mph. Both of these locations are close to the end points, where the thing would still be under acceleration anyway, and if you really wanted to run at 800mph through them, there are 14km radius turns available in the area.
Q: How do you elevate?
A: you place them under ground
Wrong, this is one of the key features here – it's overground, so that it doesn't involve expensive tunnelling, and can have solar cells on top of it to power the thing.
Q: G-Forces .. r=500m or so
A: www.wikipedia.org calculate how big a circle must be, to put only 2-3 G-s on the body, it's not that big
Bear in mind that most humans never experience even 2g acceleration. About the most likely place they are to experience 2g is at a go-kart track, and for most, 45 minutes of that will give them neck ache because their neck muscles are not used to supporting their head under that load. You'd need to keep cornering forces to under 0.5-1g, but even that requires 14km radius turns.
It does run along freeways. You're making a false assumption that because something wasn't designed to carry things at 800mph, it can't carry them at that speed. the vast majority of the freeways are dead straight, or involve only very gentle curves. The small areas where the curves are too tight can be shortcut across, which will indeed require a small amount of land grab, but this is being proposed as an alternative to a rail link that would involve a land grab along its entire length, so that's already a vastly simplified problem.
It doesn't matter if they were designed for it or not. They happen to be straight enough anyway, bar a very few locations. This simplifies the land grab issue thousands of fold. Given that this is being proposed as an alternative for a rail link that requires a land grab along its entire route, that's a massively simplified problem.
Land is going to be what kills this project, before it even gets as far as anything technical. How do you acquire the land for the route as a private entity, without eminent domain?
If you had even read the basic media coverage of this, you would know that he is proposing mounting this over the central reservation on freeways, so no land purchasing would be necessary.
Sheesh, it's an argument, some points are insightful, others are a little over the top and baitish. But why can't people just let each other discuss why they have differing opinions and attempt to enlighten themselves?
It's actually kinda amusing to see this argued. The entire basis for the GPL is "people who use and extend my code can't distribute under their own terms –they are restricted to doing something that's good for users instead. If you don't like that, don't use my source".
To see it argued that those people were morally consistent to say "no, take it down from the app store, developers' rights are more important than users' ones" is pretty funny.
Right, that's not because these users are not aware that there's a threat of getting some kind of malware on their machine. This is because the problems caused by the antivirus software are as bad as the problems caused by a virus, so basically, you're asking them to guarantee that they have something malicious on their system, rather than simply having a 1 in a million chance that they do.