Would it surprise you to learn that nobody drives by to meter your gas usage? It's wireless to the nearest cellular uplink, usually in a wireless electric meter. Nobody has to come query it, since that would mostly defeat the point.
Older flash devices allowed multiple writes to one page, but new ones do not.
The higher-density MLC devices do not allow you to read a page, flip a bit to 0 and overwrite it. They require that pages be written just one, and in order.
This is causing no end of frustration for the Microsoft mobile filesystems, which frequently overwrote pages to flag them.
That's so oversimplified as to be completely wrong.
The number of write/erase cycles on NAND is significantly less than a hard drive. Typical devices are rated for 10,000 cycles. Bleeding-edge MLC parts can be as low as 5,000 or 7,000 erase cycles.
But.. a well-designed device will perform accurate wear-levelling across all the available blocks, so it doesn't matter what kind of access the user performs -- the whole device will wear evenly.
There are indeed reserve blocks to mitigate premature death of some parts.
But, the most important part is the ECC mechanism. The parts don't just wear out and die, they get an increasing bit error rate. By overdesigning the ECC logic, you can squeeze longer life out of the parts.
It does not play guess and check.. well-recognized error correction algorithms like Reed-Solomon or BCH are used with really high detect/correct rates.
Once you have accurate wear levelling, excellent ECC, and some manner of failure prediction, then it doesn't make so much sense to keep all your flash "in reserve" ready to swap out other parts wholesale. You might as well involve all the parts in the mix, so you get longer wear throughout.
MLC brings more density to the table. That's the only reason they do it. Smaller die size and storage density means more MB per dollar
SLC would be a much smaller capacity drive for the same money. It would be faster at writing, but probably too expensive or too small to have many adopters.
Same reason SLC is all but unheard-of in thumbdrives. (IronKey being one exception.)
One of the biggest challenges of the coming years will be finding and developing filesystems (logical data stores) that take advantage of the strengths of flash memory while deminishing the weaknesses of it.
Our approach today is mapping large banks of Flash to look like a hard drive, and then using a filesystem that is optimized to reduce seek activity. (Cyl/Hds/Tracks-per-Sector..)
EXT3 on SSD, FAT on huge SD cards, it's just shoe-horning our old filesystems onto new media. It makes about as much sense as using a hard drive to store a single TAR image only.
Once we make the huge step of designing high-performance filesystems that are exclusively *for* flash media, then we can take advantage of some of the huge benefits that are distinctly flash.
Key things like journalling should be designed with the flash organization in mind: pages and blocks vs "sectors". That kind of thing.
Flash does have "access time" close to RAM, since it doesn't have to seek or do complex addressing.
When you have these huge banks of flash acting as one drive, then "access time" becomes a computational problem of how fast you can look up the physical location of the user's data, based on a logical sector address.
Still faster then mechanically moving a drive head, of course.
Again, it's only the ERASE unit that is huge -- 64KB, 128KB, or 256KB on the device itself.
You can't erase 4KB alone.
It gets more complicated when you consider huge parallel arrays of NAND, and the complex logical remapping that goes on to give the appearance of a typical 512-byte sector device.
NAND blocks are *erased* in large blocks, probably 128KB or larger in this case.
However, the read and write operations occur at a *page* level, not block. NAND pages today are typically 2K or 4KB in size.
So you can read and write in smaller units than 128KB.
However, to erase any byte of the NAND, you have to relocate the preserved data and erase a whole block.
Because these drives operate on huge aggregate arrays of NAND, their block structure may be much larger, or they may have very complicated and smart algorithms to re-map write new data while waiting to perform erases much later.
When cells age, they take longer to erase. This happens over 5,000, 10,000 cycles or longer. It's not dramatic, and eventually the cells fail in a way more severe than can be corrected by the ECC.
Because there is a (software) process to bring full speed back to the drive, we can safely conclude that none of the slowdown is related to cell aging or other cell-level issues. It's more of an organization and fragmentation issue.
Then came flash cards. Here's a thing a lot of people don't know: flash actually DOES come in binary sizes. That's how it's manufactured. Uh, no. You can make flash in any size you like. It's just a number of NAND or NOR cells, and there's no reason at all that they have to be in power-of-two sizes. Most of the size limits (SD = 2GB, SDHC = 32GB) are actually power-of-two counts of 512-byte sectors, but the media can be any size up to that.. any number of sectors.
The basic pages and blocks of flash are themselves not powers of two! Most 512-byte page NAND devices have some number (~16) bytes of extra area in each page for bad block management, spare bits, and ECC. It's really arbitrary.
Indeed, most flash cards are odd-sized when you count the sectors, just like disk drives, and for much the same reason -- the ECC logic, bad block reserve, and logical sector tracking take some amount of space. Don't take my word for it, check for yourself! Grab a handful of 4GB cards and see if any two brands have exactly the same number of sectors.
Back when cards were smaller, 12MB, 80MB (Lexar) and 96MB (i2GO) CompactFlash cards were not uncommon.
All 11 XBox360 probably spent their life in the sweltering heat of an Ikia "stereo cabinet", nestled between a 500W amplifier and a digital cable receiver with no fan of its own.
There, gasping for heated breath behind a tinted-glass door, the XBox baked under a rush of hot air.
Where does this myth come from? Have you tried booting WinXP from solid state? (8GB CompactFlash, for example) It's not that much faster. It's not like your machine spends all its time seeking the drive heads around during boot. "If only I had a faster seek time"
It's all the stupid delays, timeouts, and busy loops in the Win32 drivers, probing for things that probably aren't there -- waiting for other things to finish, making network connections, and so on. The actually reading-from-the-drive time, even if you made it much faster, wouldn't really mean a world of difference in boot time.
You almost understood him correctly. The full answer is "I'm telling you, no CARRIER (network provider) wants that".
And that, alphafoo, is who Kyocera sells phones to. Did you buy your phone from Kyocera? No, you did not. You bought it from Sprint, or Cingular, or Verizon..
Of course you want it, but.. Do they want you to have a simple phone that does nothing but make calls and talk on the phone? Of course not. There's no "value add" or "ARPU" upsell there..
Better than confusing phase and voltage like you have.
Standard electricity at your 120v outlet may be single-phase, but no modern home panel gets less than 240v. Your electric stove and A/C unit probably run straight off the 240v (two 120v RMS waves 180-degrees out of phase) while the rest of your house gets "split phase", with a Netural (zero) and one leg (single phase) Hot to give you 120v at the outlet.
Some outlets get one phase, the others get the opposite phase. You can verify this with an extension cord and multimeter between different outlets in the house -- you should be able to find 240v AC between two distant outlets.
First, the v710 never had OBEX support. Verizon never took it out, because it simply Wasn't There! There is no hack to enable it, because there is no OBEX code in the box. Their mistake, as explained in the lawsuit, was to mislead customers into thinking they would get something like OBEX. (Verizon does, however, disable Dial-Up Networking via Bluetooth.)
Most importantly, the latest version of the v710 software from Verizon disables the other free transport -- Transflash. You can no longer copy wallpaper and ringtones (or anything at all) from the flash card to the phone. You can't copy your own pictures from the phone internal memory to the card either!
Early v710 phones from Verizon did have this feature. In fact, it can be re-enabled by some well-published hacks. Highly Recommended.
The e815 phone, of course, does have OBEX which can be re-enabled through more well-published hacks.
Verizon also doesn't publish the more significant differences between the e815 and v710, listing only "VCast" as a feature.
40MB of memory vs 10MB
Much faster processor
Longer battery life (bigger capacity battery)
Better keypad
Nicer camera (1.3 vs 1.2MP, but also just better in general)
OBEX can be re-enabled
EvDO dial-up networking
Bluetooth calendar/Contact sync
Faster charger in the box.
Missing belt-clip in the box (e815 charges $17 extra for the same clip)
I don't get it.. this is news to me, and apparently others. Why should the product be unsupported? Doesn't matter where I bought it -- if it comes with a US warranty, then I expect support from the manufacturer. Most of the time they have no idea where I bought it from anyway.
I'm no retailer, but I thought MAP was just tied to advertising subsidies, not end-user support or lawyers.
I hate the "call us for price" game, and simply don't play it. Maybe someday the FTC will come down on this whole MAP game and flush it. Advertise the price you're willing to sell for. That is, after all, what shoppers base their, you know, shopping on.
You can't possibly be suggesting that someone shopping for a Garmin GPS should go to Every Single Store that sells them, add one to the cart and go through half of checkout just to see what the "real" price is.. That's why Froogle has "Sort By Lowest Price". I don't think I'm the only one using it.
Who says Slashdot isn't timely or Stuff That Matters.. by coincidence I was considering buying one of these, and checking into compatibility (which is surprisingly hard).
If the external pack is as awkward as described, I'm probably better off going with two or three OEM batteries and swapping them out while hibernating. At least they're not going to make the laptop lopsided.
Segway LLC will never market it this way. Can't.
on
A Killer App For Segway
·
· Score: 5, Informative
The dynamic-balancing technology was licensed (by DEKA) to Johnson & Johnson first, for use on the iBot and any other medical applications.
J&J retains the rights to *all* medical applications.
So Segway has to specifically market it as a non-medical device and never seek FDA approval of any kind because then J&J could step in and make a ruckus.
In fact, if it can be shown that the Segway is largely used by disabled/mobility-impaired people, bad things could happen to Segway LLC.
I keep seeing people chastising Segway for not persuing the disabled market, but these are the facts. Even if they wanted to go through the lengthy and expensive medical review process, they simply can not because of their business arrangement.
For some reason, if you want many 3.5" hard drive bays, you have to buy a HUGE case, as if your motherboard was proportionally huge or you needed a dozen CD-ROM drives. Whatever.
The Lian-Li PC-V2100 holds twelve 3.5" drive, and most importantly, allows space between each one for airflow. Older cases would stack the drives in contact, causing terrible heat buildup.
I think the recent Fry's 160GB for $70 sale (no rebate) spawned a whole bunch of RAID projects this week, mine included.
Slashdot Mirror
Would it surprise you to learn that nobody drives by to meter your gas usage? It's wireless to the nearest cellular uplink, usually in a wireless electric meter. Nobody has to come query it, since that would mostly defeat the point.
Amazing.. it appears you didn't even look at the post you replied to.
A bigger problem is our reluctance to move off 512-byte sectors. Who needs that fine granularity of LBA?
That's two sectors per kilobyte.. dating back to the floppy disk. And we still use this quanta on TB hard disks.
Your CF card is going to use the USB interface
This is Informative?
CF cards are actually IDE devices. The adapters that plug CF into your IDE bus are just passive wiring.. no protocol adapter needed.
It's trivial to replace a laptop drive with a modern high-density CF card, and sometimes a great thing to do.
The highest-performance CF cards today use UDMA for even higher bandwidth.
HighSpeed USB can't reasonably get over 25MB/sec from the cards using a USB-CF adapter, but you can do better by using its native bus.
Older flash devices allowed multiple writes to one page, but new ones do not.
The higher-density MLC devices do not allow you to read a page, flip a bit to 0 and overwrite it. They require that pages be written just one, and in order.
This is causing no end of frustration for the Microsoft mobile filesystems, which frequently overwrote pages to flag them.
That's so oversimplified as to be completely wrong.
The number of write/erase cycles on NAND is significantly less than a hard drive. Typical devices are rated for 10,000 cycles. Bleeding-edge MLC parts can be as low as 5,000 or 7,000 erase cycles.
But.. a well-designed device will perform accurate wear-levelling across all the available blocks, so it doesn't matter what kind of access the user performs -- the whole device will wear evenly.
There are indeed reserve blocks to mitigate premature death of some parts.
But, the most important part is the ECC mechanism. The parts don't just wear out and die, they get an increasing bit error rate. By overdesigning the ECC logic, you can squeeze longer life out of the parts.
It does not play guess and check.. well-recognized error correction algorithms like Reed-Solomon or BCH are used with really high detect/correct rates.
Once you have accurate wear levelling, excellent ECC, and some manner of failure prediction, then it doesn't make so much sense to keep all your flash "in reserve" ready to swap out other parts wholesale. You might as well involve all the parts in the mix, so you get longer wear throughout.
MLC brings more density to the table. That's the only reason they do it. Smaller die size and storage density means more MB per dollar
SLC would be a much smaller capacity drive for the same money. It would be faster at writing, but probably too expensive or too small to have many adopters.
Same reason SLC is all but unheard-of in thumbdrives. (IronKey being one exception.)
One of the biggest challenges of the coming years will be finding and developing filesystems (logical data stores) that take advantage of the strengths of flash memory while deminishing the weaknesses of it.
Our approach today is mapping large banks of Flash to look like a hard drive, and then using a filesystem that is optimized to reduce seek activity. (Cyl/Hds/Tracks-per-Sector..)
EXT3 on SSD, FAT on huge SD cards, it's just shoe-horning our old filesystems onto new media. It makes about as much sense as using a hard drive to store a single TAR image only.
Once we make the huge step of designing high-performance filesystems that are exclusively *for* flash media, then we can take advantage of some of the huge benefits that are distinctly flash.
Key things like journalling should be designed with the flash organization in mind: pages and blocks vs "sectors". That kind of thing.
Access time != sequential bulk read throughput.
Think hard drive vs flash drive.
Flash does have "access time" close to RAM, since it doesn't have to seek or do complex addressing.
When you have these huge banks of flash acting as one drive, then "access time" becomes a computational problem of how fast you can look up the physical location of the user's data, based on a logical sector address.
Still faster then mechanically moving a drive head, of course.
Again, it's only the ERASE unit that is huge -- 64KB, 128KB, or 256KB on the device itself.
You can't erase 4KB alone.
It gets more complicated when you consider huge parallel arrays of NAND, and the complex logical remapping that goes on to give the appearance of a typical 512-byte sector device.
NAND blocks are *erased* in large blocks, probably 128KB or larger in this case.
However, the read and write operations occur at a *page* level, not block. NAND pages today are typically 2K or 4KB in size.
So you can read and write in smaller units than 128KB.
However, to erase any byte of the NAND, you have to relocate the preserved data and erase a whole block.
Because these drives operate on huge aggregate arrays of NAND, their block structure may be much larger, or they may have very complicated and smart algorithms to re-map write new data while waiting to perform erases much later.
Um... no.
When cells age, they take longer to erase. This happens over 5,000, 10,000 cycles or longer. It's not dramatic, and eventually the cells fail in a way more severe than can be corrected by the ECC.
Because there is a (software) process to bring full speed back to the drive, we can safely conclude that none of the slowdown is related to cell aging or other cell-level issues. It's more of an organization and fragmentation issue.
The basic pages and blocks of flash are themselves not powers of two! Most 512-byte page NAND devices have some number (~16) bytes of extra area in each page for bad block management, spare bits, and ECC. It's really arbitrary.
Indeed, most flash cards are odd-sized when you count the sectors, just like disk drives, and for much the same reason -- the ECC logic, bad block reserve, and logical sector tracking take some amount of space. Don't take my word for it, check for yourself! Grab a handful of 4GB cards and see if any two brands have exactly the same number of sectors.
Back when cards were smaller, 12MB, 80MB (Lexar) and 96MB (i2GO) CompactFlash cards were not uncommon.
All 11 XBox360 probably spent their life in the sweltering heat of an Ikia "stereo cabinet", nestled between a 500W amplifier and a digital cable receiver with no fan of its own.
There, gasping for heated breath behind a tinted-glass door, the XBox baked under a rush of hot air.
It's probably more low-tech than that.
Heavy smoker?
Dozens of shedding pets?
A dusty parrot?
Maybe it's an air-quality thing. Smoke from his coffee roasting hobby, the BBQ restaurant next door.
Kids that play with glitter..
I'm just thinking that SOMETHING is getting into those XBox and playing havoc with the fans or optical drive.
Where does this myth come from? Have you tried booting WinXP from solid state? (8GB CompactFlash, for example) It's not that much faster.
It's not like your machine spends all its time seeking the drive heads around during boot. "If only I had a faster seek time"
It's all the stupid delays, timeouts, and busy loops in the Win32 drivers, probing for things that probably aren't there -- waiting for other things to finish, making network connections, and so on. The actually reading-from-the-drive time, even if you made it much faster, wouldn't really mean a world of difference in boot time.
The pictures make it pretty obvious that this was built on a Lotus Elise frame.
Which is a fine place to start, considering the Lotus weighs about 1900lbs with the Toyota 4cyl motor.
You almost understood him correctly. The full answer is
"I'm telling you, no CARRIER (network provider) wants that".
And that, alphafoo, is who Kyocera sells phones to. Did you buy your phone from Kyocera? No, you did not. You bought it from Sprint, or Cingular, or Verizon..
Of course you want it, but.. Do they want you to have a simple phone that does nothing but make calls and talk on the phone? Of course not. There's no "value add" or "ARPU" upsell there..
Think about it.
Better than confusing phase and voltage like you have.
Standard electricity at your 120v outlet may be single-phase, but no modern home panel gets less than 240v. Your electric stove and A/C unit probably run straight off the 240v (two 120v RMS waves 180-degrees out of phase) while the rest of your house gets "split phase", with a Netural (zero) and one leg (single phase) Hot to give you 120v at the outlet.
Some outlets get one phase, the others get the opposite phase. You can verify this with an extension cord and multimeter between different outlets in the house -- you should be able to find 240v AC between two distant outlets.
Most importantly, the latest version of the v710 software from Verizon disables the other free transport -- Transflash. You can no longer copy wallpaper and ringtones (or anything at all) from the flash card to the phone. You can't copy your own pictures from the phone internal memory to the card either!
Early v710 phones from Verizon did have this feature. In fact, it can be re-enabled by some well-published hacks. Highly Recommended.
The e815 phone, of course, does have OBEX which can be re-enabled through more well-published hacks.
Verizon also doesn't publish the more significant differences between the e815 and v710, listing only "VCast" as a feature.
I don't get it.. this is news to me, and apparently others. Why should the product be unsupported? Doesn't matter where I bought it -- if it comes with a US warranty, then I expect support from the manufacturer. Most of the time they have no idea where I bought it from anyway.
I'm no retailer, but I thought MAP was just tied to advertising subsidies, not end-user support or lawyers.
I hate the "call us for price" game, and simply don't play it. Maybe someday the FTC will come down on this whole MAP game and flush it. Advertise the price you're willing to sell for. That is, after all, what shoppers base their, you know, shopping on.
You can't possibly be suggesting that someone shopping for a Garmin GPS should go to Every Single Store that sells them, add one to the cart and go through half of checkout just to see what the "real" price is.. That's why Froogle has "Sort By Lowest Price". I don't think I'm the only one using it.
Who says Slashdot isn't timely or Stuff That Matters.. by coincidence I was considering buying one of these, and checking into compatibility (which is surprisingly hard).
If the external pack is as awkward as described, I'm probably better off going with two or three OEM batteries and swapping them out while hibernating. At least they're not going to make the laptop lopsided.
The dynamic-balancing technology was licensed (by DEKA) to Johnson & Johnson first, for use on the iBot and any other medical applications.
J&J retains the rights to *all* medical applications.
So Segway has to specifically market it as a non-medical device and never seek FDA approval of any kind because then J&J could step in and make a ruckus.
In fact, if it can be shown that the Segway is largely used by disabled/mobility-impaired people, bad things could happen to Segway LLC.
I keep seeing people chastising Segway for not persuing the disabled market, but these are the facts. Even if they wanted to go through the lengthy and expensive medical review process, they simply can not because of their business arrangement.
Verizon's "BroadbandAccess" works just great under Linux using their Airprime 5220 card. Here are instructions from someone who should know:
http://www.ka9q.net/5220.html
You may recognize him as inventor of TCP/IP, but the point is that Windows is not required at all to get maximum use from this card.
For some reason, if you want many 3.5" hard drive bays, you have to buy a HUGE case, as if your motherboard was proportionally huge or you needed a dozen CD-ROM drives. Whatever.
The Lian-Li PC-V2100 holds twelve 3.5" drive, and most importantly, allows space between each one for airflow. Older cases would stack the drives in contact, causing terrible heat buildup.
I think the recent Fry's 160GB for $70 sale (no rebate) spawned a whole bunch of RAID projects this week, mine included.