In practice, I guess whatever the NAND industry calls "BCH codes" are some subset of the true field of BCH codes. Because in practice, what I said holds true.
If you have a media where bits are interdependent with adjacent bits, use RS. If you have a media where this is not true, use "BCH ECC", whatever that means.
In the case of the hardware I'm talking about, the BCH ECC can correct 8 single bit errors individually in a field, whereas an RS ECC code using the same amount of ECC data could correct 4 symbols, where each symbol is 10 bits long. So it can correct up to 40 bits, but assuming the errors are placed randomly, it is really only half as effective, only being able to replace 4 random errors. This is with similar amounts of ECC data.
BCH is good for correcting large numbers of small errors. RS is good for correcting "bursty" errors.
You want to use BCH in media where bits bear no relation to each other, like in NAND where a cell contains only 1 or 2 bits, and adjacent cells are unaffected.
RS is better on things like hard drives where a flaw in the media is likely to produce longer runs of errors in a row. Two sequential bits on a hard drive are interdependent.
Also, the whole article is dumb. First, hard drives don't appear to be getting worse lately. Additionally, every mass storage device you use (hard drives or NAND flash) already uses error correction. Additionally, SATA uses error correction over the bus, and PCIe does too. If your machine has ECC RAM (most don't) and a SATA storage interface, then your data is already covered by ECC all the way from the storage into memory.
Secondary channels should be banned. The local NBC affiliate runs a weather channel on their.2 and it their image quality is very poor next to the local CBS affiliate (CBS bans secondary channels). And woe to me if I try to watch the.2-.5 channels on PBS. Even in SD they are block city.
I disagree Generation Kill looks good. I watched the first episode on HBOW, which is an H.264 channel on DirecTV. And it had significant blocking. The 2nd episode looked better, but still, I am spoiled by BluRay. It's worlds better, and no cable or satellite system which only allocates a few mbits is doing to ever match it. That includes U-Verse.
I'm watching "The Professionals" on BluRay right now, and the video bandwidth along is over 27mbits, even in scenes where almost nothing moves. On pans it goes over 30mbits. And this isn't even one of the best looking movies. And this 27mbits is with H.264 video (AVC). 8-10mbit H.264 (let along MPEG-2) doesn't stand a chance.
Broadcast companies (and cable systems) will keep removing bandwidth until their "HDTV" looks even worse than it already does. They advertise quantity (100 channels!), quality is rarely even mentioned.
It's easy to make an LCD more efficient, just block less light. The problem is that the contrast ratio is the difference between the least amount of light you can block and the most you can block. They've just basically made a system that isn't capable of blocking much light and so it's brighter. But at the expense of the contrast ratio.
That block size argument is the allocation block size, which must be a multiple of the interface (ATA) block size, typically a power of two multiple (audio CDs being the notable exception).
The 2K referenced in that help text is almost certainly a reference to CD-ROMs (and DVDs, etc) which have 2K blocks. This is so they can use error correction codes (ECC) more efficiently. They did this over 15 years ago. This is the same reason recent ATA HDDs now use larger blocks (internally always and over the interface optionally) and one of the reasons NAND does also.
Go ahead and make a perfect theoretical product. Now try to sell it.
Reality doesn't always jive with ideas of architecture.
SSDs (and all NAND drivers) actually try to overcome the thrashing problem by leaving "open" pages, where they have some valid data and some non-valid data. Basically, one page has the new data and one has the old data and if you try to read that area, it'll read both and merge them. As the new writes come in, they are put in the new data, until either the new area is all filled and the old one is discarded, or for other reasons the driver decides to put the two pages back into one and thus commit the merge. Sometimes it absorbs inefficient writing methods, and sometimes it fails to.
Which in unix is also the same as the VM paging size.
Windows uses these larger allocation blocks also (it goes at least to 16K IIRC), as does Mac OS.
It's the ATA block size that remains at 512B in Vista, so basically every time Windows writes, it writes 8 blocks at a time (or a multiple of that), more if you selected a larger allocation block size when formatting your volume.
Another way to look at it is that SSDs aren't optimized for Vista.
Here's a basic issue with NAND. NAND is most efficient when written in chunks of at least 128KB in size. Some NAND chips aren't even efficient until 256KB. Because this is the smallest unit that can be erased in NAND. If you write a smaller amount (say 8KB), it actually has to erase a new block, copy 120KB to the new block from the old, then write in the new 8KB. Then, if you write another 8KB, might have to do it again!
So these SSDs would be fastest if Vista would write in larger blocks. Unfortunately, 512B is the block size for ATA. There are extensions for 2KB, 4KB and 8KB blocks, but Vista doesn't implement them. And it doesn't have to, as they're optional.
Also notable is that even some regular magnetic hard drives now have native 2KB or 4KB blocks and it is written in 512B chunks, it might have to do a read-modify-write cycle to do it.
Anyway, if you know ATA until recently the LARGEST possible write was 128KB (256 blocks), to expect Vista to use writes this large or larger when many drives (like almost any under 137GB) doesn't even implement them is perhaps too optimistic. To expect it to use 2KB or 4KB blocks when 95% of drives don't implement them is perhaps too optimistic.
In the end, drive (including SSD) companies can't operate in a vacuum. They know they have to make what is useful for the customer, which means usable by the OS.
As an additional note, MacOS recently (10.4.something) added support for 2KB, 4KB, etc. blocks, but it still has difficulty using large writes too. I think when operating through the file system, it never generates a write larger than 256 blocks either (which is 128KB or more depending on block size).
That law is there to make it possible for administrators to do their work. If you are working with emails, and you happen to see a few, you don't go to jail for it.
But monitoring his bosses' email so you can tell what they are saying specifically about him is highly unlikely to be in his job description, and thus he is not protected when he does that. Nor should he be.
That can't be it. 1&2, 7&8 3&6 4&5 must be pairs. They are transmitted across as differential pairs, so they must be wired as pairs.
If you don't, you'll end up with poor noise rejection as the two wires in a pair are twisted to reject noise. It'll also mess up the impedance, which will creates echos on the wire or make it so signals don't transmit down them properly.
Nothing in that case got hot enough to melt solder. Putting a towel around is not going to heat solder enough to melt it. It's lead free solder even, it doesn't melt until 750F.
Doesn't matter who designed or made the chips. If they aren't soldered down, they won't work. And that's what the problem was. That's why X-clamps (mostly) work.
Heat is semi-tangential. If the chip is soldered down, heat won't pop it off and if it isn't soldered, any kind of movement will break it loose, even when cold. This is how MS could ship you replacement units that were RRoD out of the box. They were fine before they were shipped and were broken loose during shipping.
Most of the problem appears to be solderability problems, not a problem with chip design or manufacturing.
There is a huge promotion by WalMart. Perhaps tiny companies like WalMart and discounts that put a profile 2.0 player at $300 just slipped under your radar.
If you haven't seen any promotions, then you aren't looking closely. It's quite possible this is because you don't want to look closely, you're too busy declaring the death of BluRay to see that it isn't dying.
'I can't help but think this all must have looked different on AMD's roadmap when it was first being put together. I doubt they expected that the fastest Phenom would only run at 2.4GHz and, in doing so, would only just match the Core 2 Quad Q6600--an older product on the way out, replaced by the Core 2 Quad Q9300. That's the reality, though, and it's constrained AMD's pricing so much that the top Phenom quad core is $235. The compression through the rest of the lineup makes the triple-core value proposition suspect. Give up a core to get 200MHz more at $195? Not likely when the Phenom X4 9850 Black Edition, at 2.5GHz with an unlocked multiplier, is 40 bucks more. The logic of the pricing scheme may be internally consistent, but the stakes are too low. I'd go with the X4 9850 ten times out of ten. If, that is, I were somehow bound and determined to choose an AMD processor over one of Intel's current offerings.'
That sums it up pretty well.
First of all, that AMD can only play in the low end of the market, and second that who is going to give up a core to save $40?
I've tried to correct errors on the Wikipedia page for a relatively popular consumer product I worked on. I corrected technical errors, only to have them removed and replace with incorrect "facts" that were even footnoted as correct by links to articles which were written using the incorrect info from the Wikipedia article.
People constantly bashed on the Yugo and Chevrolet's Vega. It wasn't that they didn't go down the road perfectly for some people. It wasn't that they suited some people's need just fine, it was that they were unsafe and got people killed. Ironically, a relatively small amount of people like that but it happened. You are mistaken about the Chevy Vega. You're seemingly thinking of the Ford Pinto. The Pinto had the gas tank in the wrong spot that could rupture and catch fire in a collision, killing those inside.
The Chevy Vega's problem was the aluminum engine block often had porosity problems, which meant the block could crack or lose compression. Either of these could lead to excessive fuel/oil consumption or the engine just flat out stopping. But having your engine stop running isn't actually terribly dangerous and doesn't generally lead to death.
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That's a fantastic idea!
Now, a BluRay movie is either 25GB (single layer) or 50GB (double layer).
So grab your 50GB USB stick and trot right on down to Blockbuster and load it up with 1 movie.
That's great.
In practice, I guess whatever the NAND industry calls "BCH codes" are some subset of the true field of BCH codes. Because in practice, what I said holds true.
If you have a media where bits are interdependent with adjacent bits, use RS. If you have a media where this is not true, use "BCH ECC", whatever that means.
In the case of the hardware I'm talking about, the BCH ECC can correct 8 single bit errors individually in a field, whereas an RS ECC code using the same amount of ECC data could correct 4 symbols, where each symbol is 10 bits long. So it can correct up to 40 bits, but assuming the errors are placed randomly, it is really only half as effective, only being able to replace 4 random errors. This is with similar amounts of ECC data.
The atmosphere also contains nitrogen, so if you burn the hydrogen with air, you end up making NOxes, which are polluting.
It'd be better to hold the oxygen if you can.
Yes, I realized you could just use air if you don't mind being suboptimal on pollution, which is why my post said "possibly" in it.
BCH is good for correcting large numbers of small errors. RS is good for correcting "bursty" errors.
You want to use BCH in media where bits bear no relation to each other, like in NAND where a cell contains only 1 or 2 bits, and adjacent cells are unaffected.
RS is better on things like hard drives where a flaw in the media is likely to produce longer runs of errors in a row. Two sequential bits on a hard drive are interdependent.
Also, the whole article is dumb. First, hard drives don't appear to be getting worse lately. Additionally, every mass storage device you use (hard drives or NAND flash) already uses error correction. Additionally, SATA uses error correction over the bus, and PCIe does too. If your machine has ECC RAM (most don't) and a SATA storage interface, then your data is already covered by ECC all the way from the storage into memory.
So why add more?
Now we only have to solve the problem of storing a very flammable gas and possibly an incredibly powerful oxidizer!
I mentioned HBO and BluRay discs.
HBO isn't ad-supported. Their content IS the product, not me.
Try to keep up.
Secondary channels should be banned. The local NBC affiliate runs a weather channel on their .2 and it their image quality is very poor next to the local CBS affiliate (CBS bans secondary channels). And woe to me if I try to watch the .2-.5 channels on PBS. Even in SD they are block city.
I disagree Generation Kill looks good. I watched the first episode on HBOW, which is an H.264 channel on DirecTV. And it had significant blocking. The 2nd episode looked better, but still, I am spoiled by BluRay. It's worlds better, and no cable or satellite system which only allocates a few mbits is doing to ever match it. That includes U-Verse.
I'm watching "The Professionals" on BluRay right now, and the video bandwidth along is over 27mbits, even in scenes where almost nothing moves. On pans it goes over 30mbits. And this isn't even one of the best looking movies. And this 27mbits is with H.264 video (AVC). 8-10mbit H.264 (let along MPEG-2) doesn't stand a chance.
Broadcast companies (and cable systems) will keep removing bandwidth until their "HDTV" looks even worse than it already does. They advertise quantity (100 channels!), quality is rarely even mentioned.
That's 8k resolution. DVD only supports 0.7K resolution.
So one of steps is to cut the image down by a factor of 10 IN BOTH DIRECTIONS.
That means 99% of the pixels are thrown away before the compression even starts.
BluRay would keep 6% of the pixels, which is a lot more, but still nothing compared to the original.
And remember the theoretical resolution of IMAX is about 5x as much again (2.3x more in each direction).
And that's uselessly low.
It's easy to make an LCD more efficient, just block less light. The problem is that the contrast ratio is the difference between the least amount of light you can block and the most you can block. They've just basically made a system that isn't capable of blocking much light and so it's brighter. But at the expense of the contrast ratio.
That block size argument is the allocation block size, which must be a multiple of the interface (ATA) block size, typically a power of two multiple (audio CDs being the notable exception).
The 2K referenced in that help text is almost certainly a reference to CD-ROMs (and DVDs, etc) which have 2K blocks. This is so they can use error correction codes (ECC) more efficiently. They did this over 15 years ago. This is the same reason recent ATA HDDs now use larger blocks (internally always and over the interface optionally) and one of the reasons NAND does also.
Go ahead and make a perfect theoretical product. Now try to sell it.
Reality doesn't always jive with ideas of architecture.
SSDs (and all NAND drivers) actually try to overcome the thrashing problem by leaving "open" pages, where they have some valid data and some non-valid data. Basically, one page has the new data and one has the old data and if you try to read that area, it'll read both and merge them. As the new writes come in, they are put in the new data, until either the new area is all filled and the old one is discarded, or for other reasons the driver decides to put the two pages back into one and thus commit the merge. Sometimes it absorbs inefficient writing methods, and sometimes it fails to.
Which in unix is also the same as the VM paging size.
Windows uses these larger allocation blocks also (it goes at least to 16K IIRC), as does Mac OS.
It's the ATA block size that remains at 512B in Vista, so basically every time Windows writes, it writes 8 blocks at a time (or a multiple of that), more if you selected a larger allocation block size when formatting your volume.
Another way to look at it is that SSDs aren't optimized for Vista.
Here's a basic issue with NAND. NAND is most efficient when written in chunks of at least 128KB in size. Some NAND chips aren't even efficient until 256KB. Because this is the smallest unit that can be erased in NAND. If you write a smaller amount (say 8KB), it actually has to erase a new block, copy 120KB to the new block from the old, then write in the new 8KB. Then, if you write another 8KB, might have to do it again!
So these SSDs would be fastest if Vista would write in larger blocks. Unfortunately, 512B is the block size for ATA. There are extensions for 2KB, 4KB and 8KB blocks, but Vista doesn't implement them. And it doesn't have to, as they're optional.
Also notable is that even some regular magnetic hard drives now have native 2KB or 4KB blocks and it is written in 512B chunks, it might have to do a read-modify-write cycle to do it.
Anyway, if you know ATA until recently the LARGEST possible write was 128KB (256 blocks), to expect Vista to use writes this large or larger when many drives (like almost any under 137GB) doesn't even implement them is perhaps too optimistic. To expect it to use 2KB or 4KB blocks when 95% of drives don't implement them is perhaps too optimistic.
In the end, drive (including SSD) companies can't operate in a vacuum. They know they have to make what is useful for the customer, which means usable by the OS.
As an additional note, MacOS recently (10.4.something) added support for 2KB, 4KB, etc. blocks, but it still has difficulty using large writes too. I think when operating through the file system, it never generates a write larger than 256 blocks either (which is 128KB or more depending on block size).
That law is there to make it possible for administrators to do their work. If you are working with emails, and you happen to see a few, you don't go to jail for it.
But monitoring his bosses' email so you can tell what they are saying specifically about him is highly unlikely to be in his job description, and thus he is not protected when he does that. Nor should he be.
'There is no doubt that Microsoft has no choice but to acknowledge that the closed development model for building software doesn't work any more.'
Their reasoning is circular. It will happen because it will happen and they have no choice but to acknowledge it.
An incredibly flimsy argument at best.
That can't be it. 1&2, 7&8 3&6 4&5 must be pairs. They are transmitted across as differential pairs, so they must be wired as pairs.
If you don't, you'll end up with poor noise rejection as the two wires in a pair are twisted to reject noise. It'll also mess up the impedance, which will creates echos on the wire or make it so signals don't transmit down them properly.
Nothing in that case got hot enough to melt solder. Putting a towel around is not going to heat solder enough to melt it. It's lead free solder even, it doesn't melt until 750F.
Look at Bunnie Huang's analysis.
The problem wasn't any chip at all. It wasn't even heat. The problem was the chips were not soldered to the board.
http://www.bunniestudios.com/blog/?p=223
Doesn't matter who designed or made the chips. If they aren't soldered down, they won't work. And that's what the problem was. That's why X-clamps (mostly) work.
Heat is semi-tangential. If the chip is soldered down, heat won't pop it off and if it isn't soldered, any kind of movement will break it loose, even when cold. This is how MS could ship you replacement units that were RRoD out of the box. They were fine before they were shipped and were broken loose during shipping.
Most of the problem appears to be solderability problems, not a problem with chip design or manufacturing.
There is a huge promotion by WalMart. Perhaps tiny companies like WalMart and discounts that put a profile 2.0 player at $300 just slipped under your radar.
http://forums.slickdeals.net/showthread.php?t=827856&p=11437594&highlight=blu-ray#post11437594
If you haven't seen any promotions, then you aren't looking closely. It's quite possible this is because you don't want to look closely, you're too busy declaring the death of BluRay to see that it isn't dying.
Stolen from the techreport article you posted:
'I can't help but think this all must have looked different on AMD's roadmap when it was first being put together. I doubt they expected that the fastest Phenom would only run at 2.4GHz and, in doing so, would only just match the Core 2 Quad Q6600--an older product on the way out, replaced by the Core 2 Quad Q9300. That's the reality, though, and it's constrained AMD's pricing so much that the top Phenom quad core is $235. The compression through the rest of the lineup makes the triple-core value proposition suspect. Give up a core to get 200MHz more at $195? Not likely when the Phenom X4 9850 Black Edition, at 2.5GHz with an unlocked multiplier, is 40 bucks more. The logic of the pricing scheme may be internally consistent, but the stakes are too low. I'd go with the X4 9850 ten times out of ten. If, that is, I were somehow bound and determined to choose an AMD processor over one of Intel's current offerings.'
That sums it up pretty well.
First of all, that AMD can only play in the low end of the market, and second that who is going to give up a core to save $40?
This seems like an exercise in futility.
Are you kidding me?
The chances of the moon hitting anything in the asteroid belt is 0.
You can't just select two rocks and say they'll hit someday.
And who cares if it were true anyway? This is a discussion not about two random rocks, but two specific rocks in in a specific timeframe.
I've tried to correct errors on the Wikipedia page for a relatively popular consumer product I worked on. I corrected technical errors, only to have them removed and replace with incorrect "facts" that were even footnoted as correct by links to articles which were written using the incorrect info from the Wikipedia article.
A 1 in 450 chance that this thing will hit an asteroid in the way that makes it MORE likely to hit Earth?
Hitting anything in space is like hitting a needle in a haystack. Actually, that's vastly understating it.
There better be an explanation of exactly what it is going to hit and how it will "improve" its trajectory.
It's not Constitutional.
The Chevy Vega's problem was the aluminum engine block often had porosity problems, which meant the block could crack or lose compression. Either of these could lead to excessive fuel/oil consumption or the engine just flat out stopping. But having your engine stop running isn't actually terribly dangerous and doesn't generally lead to death.