Indeed. I always found it entertaining to see what was going on in Ruby-land: concepts from 20-30 years ago that other languages had explored (and often discarded having discovered major issues with them) being touted as new and shiny and one of the reasons why Ruby is great. Rails itself is something of an example of this: NeXT's WebObjects (of which there's been an open source reimplementation in the form of GNUstepWeb since the mid '90s) had a very similar model and was the first (or possibly second, depending on exactly how you count, but within a couple of months either way) ever web-app development framework. 20 years later, Rails is a new and exciting way of developing data-driven web applications that is completely different from anything that's come before!
The consumer-grade SSD in my laptop can happily handle 2-300MB/s of sustained writes (and, simultaneously, 200MB/s of sustained reads). If you're doing linear writes, then you're the optimal workload for wear levelling. You'll be hard pressed to find a drive that isn't guaranteed for 5 years of writes at the maximum throughput the drive can handle.
Although, as other posters have pointed out, you'll get better sequential write speed and reliability from a RAID array of slower disks.
Now what about storage durability? With 3 bits per cell, how long before the data fades?
I was under the impression that the controller would handle this. Cells are typically marked as dead once their thresholds are such that you can't guarantee that they'll hold their contents for a year (there was an interesting paper at EuroSys this year about extending the lifespan by using these cells for short-lived data and exposing that functionality to the OS). If a cell is getting close to the time when the data has been unmodified for long enough that its integrity is in danger, then the controller will use the same mechanism as wear levelling to read it and write it back (either in the same place or somewhere else). Most of the time, this will happen as part of normal wear levelling, as unmodified data are moved around to sit on cells that have been rewritten a few times and spread the wear onto some of the cells that were only written once.
Not true. In the '90s, you could buy a tape drive and one tape to back up your £120 hard drive for £100 for the drive and £20 for the tape. I remember quite a few companies including tape drives on their more expensive consumer machines for exactly this reason. The tapes have stayed about that price, but now the drive is £1000 - and that's a single drive, not a tape library. That doesn't just price it out of the market for consumers, it does for small businesses too. It won't be long before it's also too expensive for medium businesses. For very large companies like Google, it's also too expensive because the bandwidth to tape is too slow unless you buy so many drives that the cost is prohibitive.
Also, we use raw storage in the context of _individual_ incompressible backup sets, not backup data at scale, because very few places backup a high ratio of incompressible data overall.
I'm not convinced that's true. At home, my NAS uses compression, so the raw capacity of the tapes is likely the relevant one, unless the tape somehow manages to recompress lz4-compressed blocks and gain a benefit (not entirely impossible, as lz4 is optimised for speed, but pretty unlikely). At work, the NetApp filer that the tape backups run from also uses compresses and deduplicates online, so not much redundancy there either.
What's the cost of doubling your storage capacity with either technology, for a few iterations? It's buy more tapes vs. $2&%fhqwgads!!1
Not really, unless you're talking about longer backup cycles. With tape, the backup time can quite quickly become a bottleneck, so you end up needing a second jukebox.
I'd love to use tape for home use. I have a NAS that I back a couple of laptops up onto. It has 3x2TB drives in a RAID-Z configuration with compression and deduplication enabled for the backup volumes. If I could get an eSATA tape drive something with 2-4TB cartridges then I could easily back that up and store the tapes somewhere else. LTO-5 / LTO-6 would do the job. LTO-5 tapes are pretty cheap now and LTO-6 isn't too bad, but the drives are insanely expensive. For the price of the drive, I could buy two more NAS boxes with the same size disks, stick them in different people's houses, and zfs send to them periodically for backups - and still have enough money left over to pay for their electricity consumption for the next 5 years.
If LTO-6, with its 6.4TB tapes, launches with a consumer-oriented drive, then I might consider being an early adopter, just buying a couple of tapes initially and assuming that the price will go down in a few years. It won't though. And we know from history that any industry that concentrates on the high-margin high end of the market that eventually that market shrinks as the quality of cheaper low-end equivalents gradually improve until no one can justify them anymore (see SGI, US steel for examples).
However, there is another issue that is mostly unrelated: the U.S. is less densely populated than most "Western" countries, and the cost of infrastructure for providing comparable service is provably higher
And that's exactly the sort of thing that the grandparent is talking about. The vast majority of the US population lives on the coasts near the big cities, where the population density is significantly higher than most of Europe, yet the telephone networks are inferior. If you look at the population density of the USA, the nationwide statistics are skewed by the enormous areas where basically no one lives. If you focus on the areas where 95% of the population lives, the US and most of the EU have quite similar population density. Both can suck for Internet access if you're in the 5%, but the US also doesn't do a very good job for the 95%.
Of course they're not - China doesn't make them wait in line. It says 'welcome, here are where you can find people to work at your company, we'll put you in touch with local suppliers, do you need any more investors?'
People having problems with Facebook 5 years ago had some excuse. Now, there have been loads of stories in the mainstream press (TV news, front pages of newspapers) about privacy issues regarding Facebook. If you look at a company offering you something 'for free' and don't spend a bit of time wondering what they're getting out of it, then you're going to spend your life falling for scams. In the case of Facebook, the information about what they get out of it is very public and easy to find.
It's short for alternate and is the one that you use to type characters that are not part of your default character set. On some toy computers that don't have a proper keyboard with a meta key, it's used for commands, unfortunately eliminating its intended use and confining the users to ASCII.
Pepper isn't an API that is in any way portable across implementations, it's a chunk of WebKit / Chrome rendering guts that are exposed for external use. Supporting it in another browser is theoretically possible, but would be a huge investment in time and effort because you'd have to translate a lot of things from what Pepper exposes into something that makes sense in your own rendering engine and browser.
Not quite, but we're getting there. This is part of the reason why lots of people are moving to smartphones and tablets as their primary computing platforms: something with the computing power and memory of a laptop from 5 years ago is ample for their needs. If it can browse the web, play back music and video, send and receive emails, and edit basic office documents, then that's enough for a massive chunk of the population. It's not enough for everyone, and some of the people that it's not enough for have very deep pockets.
I was recently talking to someone at ARM about Moore's law and how it applied to different market segments. Moore's law says that the number of transistors that you can get on an IC for a fixed cost doubles every 12 months. In desktop processors, that's meant that the price has stayed roughly constant but the number of transistors has doubled. In the microcontroller world, they've been using about half of the Moore's Law dividend to increase transistor count and half to reduce cost. A lot of customers would rather have cheaper microcontrollers than faster ones and getting ones that are a bit faster and a bit cheaper every generation is a clear win (faster reduces development costs, cheaper reduces production costs). I just got a Cortex M3 prototyping board. It's got 64KB of SRAM, 512KB of Flash, and a 100MHz 3-stage pipelien. That's an insane amount of processing power and storage in comparison to the microcontrollers of 20 years ago, but it's nowhere near as big a jump as mainstream CPUs have made. It used to be that a microcontroller was a CPU from 10 years earlier (that's about the time for the Z80, for example, to go from being a CPU in home computers to being an embedded microcontroller), but the M3 isn't even as powerful as the MIPS chip from 1993, by quite a long way. The M0 has the same transistor count as the very first ARM chip back in the early '80s.
I've not noticed any slowness and the Cortex A7 is not exactly a nippy CPU. Sure, it's quad-core, but in terms of performance (and power consumption and die area), those four cores all add up to about the same as a single Cortex A15.
I switched to Opera back then (and actually paid for it). I then went to Safari when I got a Mac because all of the other Mac web browsers had crappy integration with the rest of the UI. This has improved a bit, and I'm quite tempted to start using Firefox again on the desktop. I like the UI in new versions, but I don't like the lack of security. Once they start sandboxing tabs properly, I'd be very tempted to switch. Lack of keychain integration was an annoyance, but apparently there's an extension for that.
Right, the 'exponential growth' thing seems to assume that it can just start connecting to other computers and use them and completely ignores the fact that the speed of light is really, really slow. It's pretty slow when you're dealing with the distance from one side of an IC to another. It's annoyingly slow when you're trying to send signals between chips on the same circuit board. Once you get off-site, then it's likely to be the bottleneck.
Effective policing depends on the consent of the police. Once respect for, and willingness to cooperate with, the police goes away then they're going to have an increasingly hard time. The easiest way to alienate the police (and therefore make their jobs harder) is to pass a load of laws that guarantee that everyone is guilty of something. Why would anyone sane cooperate with the police when pretty much anything that they say will incriminate them, using laws that they didn't even know existed?
That's fine. We'll just make sure that, unless you drive it entirely on roads that you own, you're liable for every accident that you're involved in that would have been avoided if you'd had sub-millisecond reaction time, including ones where your car isn't part of a collision but impacts the fuel economy of nearby drivers or causes others to collide having determined that avoiding you will have a lower probability of a fatality. Oh, and we will insist that you have insurance that's willing to cover all of these costs before you're allowed on the public roads.
I'm sure I'll have to do something major to it eventually, but for the last decade or so, it's cost me less than 100 dollars a year
I think the USA is pretty unique in that regard. Here, if you intended to drive it on the roads, you'd need it to be taxed and insured (third-party, at least), which would make the cost per year far more than $100.
The people who think that self-driving cars and not owning cars are a good idea tend to be people who live in dense urban areas and know little to nothing about the rest of the world.
I grew up in the countryside and now live in a small city where I can cycle verywhere, so I've seen both sides of this. The problem with this argument is that you forget how population density works. The people who live deep in the countryside are basically noise, statistically speaking. If a solution works for everyone else, then no one cares if they're going to keep needing private cars - it's just one more expense to counter their very low property prices.
Like it or not, any self-driving highway is going to have to make accommodations for human guided vehicles.
Or some people are going to have to flip their switch from manual to automatic when they get near populated areas.
In addition, I somehow don't think that police, fire, ambulance, politicians, etc. would be willing to use self-driving cars
Politicians already have other people drive them. Ambulances and fire engines would be a lot safer if they plugged into a control system that made other cars get out of their way, rather than relying on humans to react sensibly to a siren in the distance. Police would almost certainly want a non-networked version with a manual override, as they are very likely to have an active adversary.
We've had fully automated trains (and trams) for well over a decade. Most of the reason that they're not widespread is consumer confidence. Some carry a human 'driver' whose entire job is to sit there and press the emergency stop button if the computer breaks.
Before the anti-terrorism rules required them to be locked, I asked if I could see the cockpit on a flight I was taking (1998ish, I think). While I was there, the pilot received a radio message telling him to turn onto a new heading. He acknowledged, then adjusted a dial to the new heading. The plane then gently rolled, turned, and levelled out. About the only things that the pilots actually do on a modern airliner are take off and land in adverse conditions (in normal conditions the computer does it) and relay messages from ATC to the computer.
I'm not sure if ZipCar works differently in the US to the UK, but here it has the slightly annoying requirements that you have to return the vehicle to the place you collected it from. That means that it's very expensive if you want to take it for a trip to another town (you can't leave it in a bay there for someone else to use while you're away and then pick either it or a different one up for the return trip a few hours / days later).
You can't remove my State's direct democracy by simply believing we don't have it
The only places I am aware that practice direct democracy are the Swiss Cantons and some parts of Israel. Which state do you live in the I should add to this list?
Slashdot Mirror
Indeed. I always found it entertaining to see what was going on in Ruby-land: concepts from 20-30 years ago that other languages had explored (and often discarded having discovered major issues with them) being touted as new and shiny and one of the reasons why Ruby is great. Rails itself is something of an example of this: NeXT's WebObjects (of which there's been an open source reimplementation in the form of GNUstepWeb since the mid '90s) had a very similar model and was the first (or possibly second, depending on exactly how you count, but within a couple of months either way) ever web-app development framework. 20 years later, Rails is a new and exciting way of developing data-driven web applications that is completely different from anything that's come before!
The consumer-grade SSD in my laptop can happily handle 2-300MB/s of sustained writes (and, simultaneously, 200MB/s of sustained reads). If you're doing linear writes, then you're the optimal workload for wear levelling. You'll be hard pressed to find a drive that isn't guaranteed for 5 years of writes at the maximum throughput the drive can handle.
Although, as other posters have pointed out, you'll get better sequential write speed and reliability from a RAID array of slower disks.
The only market for 15kRPM drives is people who care more about IOPS than about capacity. That market switched to SSDs some years ago.
Now what about storage durability? With 3 bits per cell, how long before the data fades?
I was under the impression that the controller would handle this. Cells are typically marked as dead once their thresholds are such that you can't guarantee that they'll hold their contents for a year (there was an interesting paper at EuroSys this year about extending the lifespan by using these cells for short-lived data and exposing that functionality to the OS). If a cell is getting close to the time when the data has been unmodified for long enough that its integrity is in danger, then the controller will use the same mechanism as wear levelling to read it and write it back (either in the same place or somewhere else). Most of the time, this will happen as part of normal wear levelling, as unmodified data are moved around to sit on cells that have been rewritten a few times and spread the wear onto some of the cells that were only written once.
Tape was never alive for consumers
Not true. In the '90s, you could buy a tape drive and one tape to back up your £120 hard drive for £100 for the drive and £20 for the tape. I remember quite a few companies including tape drives on their more expensive consumer machines for exactly this reason. The tapes have stayed about that price, but now the drive is £1000 - and that's a single drive, not a tape library. That doesn't just price it out of the market for consumers, it does for small businesses too. It won't be long before it's also too expensive for medium businesses. For very large companies like Google, it's also too expensive because the bandwidth to tape is too slow unless you buy so many drives that the cost is prohibitive.
Also, we use raw storage in the context of _individual_ incompressible backup sets, not backup data at scale, because very few places backup a high ratio of incompressible data overall.
I'm not convinced that's true. At home, my NAS uses compression, so the raw capacity of the tapes is likely the relevant one, unless the tape somehow manages to recompress lz4-compressed blocks and gain a benefit (not entirely impossible, as lz4 is optimised for speed, but pretty unlikely). At work, the NetApp filer that the tape backups run from also uses compresses and deduplicates online, so not much redundancy there either.
What's the cost of doubling your storage capacity with either technology, for a few iterations? It's buy more tapes vs. $2&%fhqwgads!!1
Not really, unless you're talking about longer backup cycles. With tape, the backup time can quite quickly become a bottleneck, so you end up needing a second jukebox.
I'd love to use tape for home use. I have a NAS that I back a couple of laptops up onto. It has 3x2TB drives in a RAID-Z configuration with compression and deduplication enabled for the backup volumes. If I could get an eSATA tape drive something with 2-4TB cartridges then I could easily back that up and store the tapes somewhere else. LTO-5 / LTO-6 would do the job. LTO-5 tapes are pretty cheap now and LTO-6 isn't too bad, but the drives are insanely expensive. For the price of the drive, I could buy two more NAS boxes with the same size disks, stick them in different people's houses, and zfs send to them periodically for backups - and still have enough money left over to pay for their electricity consumption for the next 5 years.
If LTO-6, with its 6.4TB tapes, launches with a consumer-oriented drive, then I might consider being an early adopter, just buying a couple of tapes initially and assuming that the price will go down in a few years. It won't though. And we know from history that any industry that concentrates on the high-margin high end of the market that eventually that market shrinks as the quality of cheaper low-end equivalents gradually improve until no one can justify them anymore (see SGI, US steel for examples).
However, there is another issue that is mostly unrelated: the U.S. is less densely populated than most "Western" countries, and the cost of infrastructure for providing comparable service is provably higher
And that's exactly the sort of thing that the grandparent is talking about. The vast majority of the US population lives on the coasts near the big cities, where the population density is significantly higher than most of Europe, yet the telephone networks are inferior. If you look at the population density of the USA, the nationwide statistics are skewed by the enormous areas where basically no one lives. If you focus on the areas where 95% of the population lives, the US and most of the EU have quite similar population density. Both can suck for Internet access if you're in the 5%, but the US also doesn't do a very good job for the 95%.
Of course they're not - China doesn't make them wait in line. It says 'welcome, here are where you can find people to work at your company, we'll put you in touch with local suppliers, do you need any more investors?'
People having problems with Facebook 5 years ago had some excuse. Now, there have been loads of stories in the mainstream press (TV news, front pages of newspapers) about privacy issues regarding Facebook. If you look at a company offering you something 'for free' and don't spend a bit of time wondering what they're getting out of it, then you're going to spend your life falling for scams. In the case of Facebook, the information about what they get out of it is very public and easy to find.
It's short for alternate and is the one that you use to type characters that are not part of your default character set. On some toy computers that don't have a proper keyboard with a meta key, it's used for commands, unfortunately eliminating its intended use and confining the users to ASCII.
Pepper isn't an API that is in any way portable across implementations, it's a chunk of WebKit / Chrome rendering guts that are exposed for external use. Supporting it in another browser is theoretically possible, but would be a huge investment in time and effort because you'd have to translate a lot of things from what Pepper exposes into something that makes sense in your own rendering engine and browser.
Not quite, but we're getting there. This is part of the reason why lots of people are moving to smartphones and tablets as their primary computing platforms: something with the computing power and memory of a laptop from 5 years ago is ample for their needs. If it can browse the web, play back music and video, send and receive emails, and edit basic office documents, then that's enough for a massive chunk of the population. It's not enough for everyone, and some of the people that it's not enough for have very deep pockets.
I was recently talking to someone at ARM about Moore's law and how it applied to different market segments. Moore's law says that the number of transistors that you can get on an IC for a fixed cost doubles every 12 months. In desktop processors, that's meant that the price has stayed roughly constant but the number of transistors has doubled. In the microcontroller world, they've been using about half of the Moore's Law dividend to increase transistor count and half to reduce cost. A lot of customers would rather have cheaper microcontrollers than faster ones and getting ones that are a bit faster and a bit cheaper every generation is a clear win (faster reduces development costs, cheaper reduces production costs). I just got a Cortex M3 prototyping board. It's got 64KB of SRAM, 512KB of Flash, and a 100MHz 3-stage pipelien. That's an insane amount of processing power and storage in comparison to the microcontrollers of 20 years ago, but it's nowhere near as big a jump as mainstream CPUs have made. It used to be that a microcontroller was a CPU from 10 years earlier (that's about the time for the Z80, for example, to go from being a CPU in home computers to being an embedded microcontroller), but the M3 isn't even as powerful as the MIPS chip from 1993, by quite a long way. The M0 has the same transistor count as the very first ARM chip back in the early '80s.
I've not noticed any slowness and the Cortex A7 is not exactly a nippy CPU. Sure, it's quad-core, but in terms of performance (and power consumption and die area), those four cores all add up to about the same as a single Cortex A15.
I switched to Opera back then (and actually paid for it). I then went to Safari when I got a Mac because all of the other Mac web browsers had crappy integration with the rest of the UI. This has improved a bit, and I'm quite tempted to start using Firefox again on the desktop. I like the UI in new versions, but I don't like the lack of security. Once they start sandboxing tabs properly, I'd be very tempted to switch. Lack of keychain integration was an annoyance, but apparently there's an extension for that.
Right, the 'exponential growth' thing seems to assume that it can just start connecting to other computers and use them and completely ignores the fact that the speed of light is really, really slow. It's pretty slow when you're dealing with the distance from one side of an IC to another. It's annoyingly slow when you're trying to send signals between chips on the same circuit board. Once you get off-site, then it's likely to be the bottleneck.
Effective policing depends on the consent of the police. Once respect for, and willingness to cooperate with, the police goes away then they're going to have an increasingly hard time. The easiest way to alienate the police (and therefore make their jobs harder) is to pass a load of laws that guarantee that everyone is guilty of something. Why would anyone sane cooperate with the police when pretty much anything that they say will incriminate them, using laws that they didn't even know existed?
That's fine. We'll just make sure that, unless you drive it entirely on roads that you own, you're liable for every accident that you're involved in that would have been avoided if you'd had sub-millisecond reaction time, including ones where your car isn't part of a collision but impacts the fuel economy of nearby drivers or causes others to collide having determined that avoiding you will have a lower probability of a fatality. Oh, and we will insist that you have insurance that's willing to cover all of these costs before you're allowed on the public roads.
I'm sure I'll have to do something major to it eventually, but for the last decade or so, it's cost me less than 100 dollars a year
I think the USA is pretty unique in that regard. Here, if you intended to drive it on the roads, you'd need it to be taxed and insured (third-party, at least), which would make the cost per year far more than $100.
The people who think that self-driving cars and not owning cars are a good idea tend to be people who live in dense urban areas and know little to nothing about the rest of the world.
I grew up in the countryside and now live in a small city where I can cycle verywhere, so I've seen both sides of this. The problem with this argument is that you forget how population density works. The people who live deep in the countryside are basically noise, statistically speaking. If a solution works for everyone else, then no one cares if they're going to keep needing private cars - it's just one more expense to counter their very low property prices.
Like it or not, any self-driving highway is going to have to make accommodations for human guided vehicles.
Or some people are going to have to flip their switch from manual to automatic when they get near populated areas.
In addition, I somehow don't think that police, fire, ambulance, politicians, etc. would be willing to use self-driving cars
Politicians already have other people drive them. Ambulances and fire engines would be a lot safer if they plugged into a control system that made other cars get out of their way, rather than relying on humans to react sensibly to a siren in the distance. Police would almost certainly want a non-networked version with a manual override, as they are very likely to have an active adversary.
It's basic queueing theory. Decelerating slightly on a free-flowing road can cause traffic jams a few miles behind you.
We've had fully automated trains (and trams) for well over a decade. Most of the reason that they're not widespread is consumer confidence. Some carry a human 'driver' whose entire job is to sit there and press the emergency stop button if the computer breaks.
Before the anti-terrorism rules required them to be locked, I asked if I could see the cockpit on a flight I was taking (1998ish, I think). While I was there, the pilot received a radio message telling him to turn onto a new heading. He acknowledged, then adjusted a dial to the new heading. The plane then gently rolled, turned, and levelled out. About the only things that the pilots actually do on a modern airliner are take off and land in adverse conditions (in normal conditions the computer does it) and relay messages from ATC to the computer.
I'm not sure if ZipCar works differently in the US to the UK, but here it has the slightly annoying requirements that you have to return the vehicle to the place you collected it from. That means that it's very expensive if you want to take it for a trip to another town (you can't leave it in a bay there for someone else to use while you're away and then pick either it or a different one up for the return trip a few hours / days later).
You can't remove my State's direct democracy by simply believing we don't have it
The only places I am aware that practice direct democracy are the Swiss Cantons and some parts of Israel. Which state do you live in the I should add to this list?