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Next Wave Of Hard Drive Tech: Perpendicular Recording
angrytuna writes "New serial technologies are set to replace standard SCSI and ATA (Advanced Technology Attachment) interfaces over the next two years, even as hard-disk drive manufacturers prepare for an entirely new form of bit storage. Perpendicular recording will replace longitudinal recording in storage devices, placing bits on end instead of lying them parallel on the disc surface, thus dramatically increasing the possible storage density."
that there is such a crackdown on file-sharing. If they take that away from us, then whats the point of having that much space?
I wonder which side of the debate the hard-disk manufacturers are on?
If my drive bit is standing up, it must be hard. Ergo, hard drive.
C|N>K
the hard drive sideways... voila! perpendicular recording ;)
I am less concerned about the amount of stuff I can put on a hard-drive, and more concerned that the next time I boot up my computer, that stuff will still be there, as harddrives get more and more high-tech, the reliability seems to be taking a big nosedive, how will this effect the reliability of future drives?
Why does the article reference interfaces then talk about a new way of storing the bits on the disk survace?
In the days of 250GB hard drives, who cares? All I'm concerned about is the speed of drives. Lets improve that for once...
Does anyone have a link to a description of this that's more detailed than "stacking bits on end"?
Are they using platters with trenches and storing information on the sidewalls?
Are they using some means of reading and writing at many depths within the platter without disturbing other layers?
The article says the technology has been under investigation for 20 years, so presumably there's a forest of technical literature on it.
HDD manufacturers said they expect to start replacing 3.5in. disk drives with smaller 2.5in. devices in enterprise products sometime within the next year.
Why would they want to do this? Has it something to do with vibrations (or even shattering a disk) due to the extreme rpm's that these drives are running?I don't know much about this stuff, so could someone please enlighten me?
The best weapon of a dictatorship is secrecy, but the best weapon of a democracy should be the weapon of openness.
This conversation with Jim Gray, head of Microsoft's Bay Area Research Center, has grim, eye-opening comments on the growing gap between storage densities and access speeds/bandwidth. Currently the most effective way to send a multi-terabyte disk array is by UPS -- turns out a UPS truck has a "bandwidth" equivalent to about 7 megabytes/second. And the problem of practical access speeds is only going to get worse. At current and near-future access speeds, searching a 20-terabyte disk might take a year.
Storage density is one thing, but storage speed is another. With 200 GB hard drives readily available, and relatively cheap, the main thing I'm itching for is increased access and transfer speeds. Not just the controller speed as most hard drives still only maintain a constant transfer speed of 33Mbps. Theoretically, a denser drive at the same rotational speed will transfer data faster than a less dense drive, but will we see a dramatic improvement in sustained transfer speeds? While this transfer speed is acceptable while watching a DivX movie, it's really a pain while ripping a DivX movie. (A movie that I shot in my backyard, and authored, and own the rights to, and am ripping for the pure exitement as I would never violate a copyright.)
Of course, both of these are non-magnetic. And holographic memory is still research-only, as far as I know.
I wonder, will magnetic storage (in any number of dimensions) ever get eclipsed by non-magnetic ones like these?
Nothing is so smiple that it can't get screwed up.
Forget that crap. We all know that isn't practical. Just use smaller fonts. That works today.
Could someone explain (/point me to a website) as to what this paragraph means?
"We always have concerns about new connectors and backplane designs but those problems are minimized in a serial environment where the wiring is point-to-point,"
"Connecting devices fast is a lot easier when there's only two of them."
If they stand the 1's up, sure you can fit more because they're skinny. But 0's? They're wide...I don't see a significant amount of savings there...
So, does this mean that instead of looking like this:
0
1
All of my bits will instead look like this?:
_
-
I suppose you can squeeze a lot more of them together that way, but is that really much of an innovation?
Now, if they had figured out a way to fold the suckers, I'd be impressed.
...engineers are working with software developers on a way to dramatically reduce power consumption by maximizing the number of 0-bits in memory.
The grain of truth to this joke: There is a well-known technique that reduces the number of 1s in words transmitted on a bus by inverting words that are more than half 1 (and setting an extra bit indicating that the word has been inverted). The idea is to reduce the number of transitions on the bus lines, as a change in state is what dissipates power.
More relevant than this technology that is still many years away, I find much more interesting the part about the desktop industry moving to 2.5" drives. So in the next year or so we'll be able to buy very high density, fast drives that can fit in a pocket and already have serial interfaces! All we need are sata jacks on the front panel and the world moves one giant leap closer to true "plug-n-play" goodness. Mail order sneakernets just got even cheaper!
I have seen a few posts from folks not quite understanding how the "bits-on-end" approach works. Some were speculating that it might be holographic, multiple layers, or 3D and such. It is not at all that complicated as they are making it out to be. I heard it best described from Alan Shugart who started the company called Seagate. On an episode from "The Computer Chronicles" back in 1984 he described it as standing the magnetic particles on end to fit more in a given area, which is similar to how a cord of wood could fit into a given smaller area by standing them up on end instead of laying flat. So it really is simpler than you might imagine. Of course the implementation is anything but simple. This is especially evident by the fact that this idea was known as a way to increase storage density back in 1984, when even 200 million bits per square inch was not in a consumer product yet. It was merely in labs with thin film head technology poised to become the next big thing in a short time from that year.g er.php.
By the way, you can see old episodes of "The Computer Chronicles" at the Prelinger Archives collection.
http://www.archive.org/movies/prelin
I believe Slashdot had a story about that a while ago. Good stuff! Great info can be had through those old episodes about computer history.
>>>>>> Chewie, take the professor in the back and plug him into the hyperdrive.
I'm curious to, but i think it's something like this. If I have a log laying on the ground i can rotate it around to put it in it's proper place. But if i stand it on end and rotate it about its axis to get it in its differant positions its not covering nearly as much space. But keaping it standing up is the problem since it naturaly wants to fall over, and you can't attach the base of it to the ground very well if your going to be spinning it all the time.
This is just my thought on what there doing. But how data is actualy stored on a disk is a mystery to me, all i have is guesses. Soon as i think that one little thing not going the right way destroys a file causes me to think it must be weird magic voodoo.
One of the first Sun machines I used was a 3/160 with an external gigabyte disk array. The array was a washing machine size enclosure with a pair of 800 MB SMD disks with 8" platters. In 1994 this was a huge disk, in more ways than one!
Interestingly, my little 486 with its 340 MB drive were far faster than the old Sun, and even competitive with the newer SparcStations. 7200 RPM baraccudas in modified enclosures (extra fans and breathing holes made the difference between life and death) were even faster when they arrived.
After working exclucively with laptops for the past two years, I can see a clear parallel between the old 2.5" -> 2.5" transition and the 8" -> 5.25" -> 3.5" transitions in the past. Sure I keep a pair of 120 GB 3.5" disks in firewire enclosures around, but the 60 GB disk in my powerbook and the 30 GB disk in my Dell i8000 are more than adequate for daily use. My ipod even has 30GB, which is enough for my favorite music, the Warthog Jump video and a few other fun things.
With emphasis on blade and 1-U servers, as well as cardcage oriented telecom gear, I can see a lot of value for 2.5" disks in the telecom and server markets.
AFAICT, they're not talking about multi-layer recording, they're just standing the existing bits on end so that the same amount of magnetic material uses up less surface real-estate. <deadpan>If they did multi-layer recording, they'd have to slow the drives down so that the surface of the disk wasn't so stretched by centrifugal "force" and the shallower bits didn't sag into the next cylinder. Otherwise they'd have to angle the heads WRT the platter surface, which means they can't fly them close enough to record that deep.</deadpan>
Got time? Spend some of it coding or testing
Interesting? This clueless and sadly-late attepmpt at a FP is misleading everyone that reads it!. And you mods are to blame -- that's right: YOU!
::::::::
::::::::
Grrr, RTFA: there is nothing "3D" about it. It's still a 2-dimensional array of bits on a platter. The density increase comes from standing the little areas of magnetic media on end, instead of laying down. So, a top view of the old scheme would look like:
||||||||
||||||||
The new scheme, from the top:
In this case 2x density, as the lower one has twice as many dots in the same area as the dashes of the upper. (That is, each dot or dash represents the area of the physical medium used to store one bit by changing its magentic orientation). Get it? No 3-d. No holograms. Just 2-4x density increase by changing the orientation of the bits from parallel to perpendicular (relative to the disk platter surface).
everything in moderation
Okay for the last 20 years they've been working on this. WHY are they not looking into solid state storage? There are plenty of companies within 2 years will have drives that will blow away current drives in speed and capacity. One such company is using nanotech to offer 1 terabit per cm2. And it'll run at 10x the speed of current memory.
I cant help to see how this is not wasted time trying to improve the platter drives in favor of pushing out solid state storage faster. The advantages alone overrule more development on platter systems. Imagine instead of 100mbps of bandwidth on the hard drive you would be getting 10gbps of throughtput, no moving parts and much less heat and a longer MTBF time along with size alone this would blow away the server markets..
Who would care about the 16Gig memory limit when you have a solid state hard drive that ran faster than the memory array? Then you can just modify the software to use the Solid State Array (Think I'm going to patent this!hehe) SSA drive as memory and storage thus DB servers would have serious improvements compared to platter systems.
http://www.inphase-tech.com/technology/
Weren't the 2.88MB floppy discs perpendicular recording also?
I distinctly remember reading that somewhere.
-- The universe began. Life started on a billion worlds...
-- Except on one where stupidity was there first.
See, there's a limit to how many bits you can store on a disk. I see. Because the area of the disk is limited I see. But you don't want a limit, you want more space. I want more space. But you can't have more space, because all of the bits are square they're square. and there's only so many square inches of surface. Only so much. Yes. Look at this disk. Radius 3.25" 3.25 It's a circle. It's round. Pie-R-square Pie-R-square So the area's limited. I see.
And the bits, they're almost square, because that's the way the manufacturers' engineers like them. They like squares? Yes. I see. Well, really they're not square, they're almost square. And how's that? Well, they're square sections of a round arc. Not square? But almost square. Almost square. I see.
So what do we do? I don't know. Well, we get a better packing fraction. Better packing fraction? Yes. That's the key. A better packing fraction. I see. And your data is round. Data is round Because the magnetic field is round. I see. And a square doesn't approximate a circle very well, does it? No. What does it better? A circle? Well, yes, but you can't do it with a circle, because circles bump each other. They bump each other? Yes, and they leave empty space between them. And we want a better packing fraction? Yes. So what do we take a cue from? I don't know. I know you don't know, but I'll tell you. We take a cue from the bee. The bee? The honeybee. He uses hexagons. Aaah. Hexagons. Yes, hexagons. They're all the future. The future? The future. The future. Yes, the future. Hexagons. Yes. That's where the money is. You're a nut.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
People seem to forget that if the media industries (all hated virulently on slashdot, it seems) are going to make money in the future with digital transfer, they'll need a means to shove content onto our local drives so we can watch it from there. In fact, one of the things that makes me suspicious regarding this new quantitative leap in storage... is that these drives might be DRM enabled in hardware.
Yes, even if P2P is banned somehow, these high capacity drives will be needed. From the point of view of Hollywood, it is imparative that they be widespread, so they can shovel content onto them and charge us their appropriate fees for doing so.
Not saying it's good or bad, just that it is.
If you have no idea what the difference between Longitudinal Recording and Perpendicular Recording might be, and the phrase "stands the bits on end" meant absolutely nothing to you because its an utterly ridiculous way to explain it, here's the lodown. Longitudinal recording is what we use today in everything from cassette tape to hard disks. It works by magnetising tiny sections of the recording medium. You can imagine the magnetised sections as tiny bar magnets laid end-to-end. The read head detects transitions in the direction of the magnetic field.
.
<- -> <-- -> <- -->
In the above diagram we're looking down at one track on the surface of a platter. Perpendicular recording works differently. The "magnets" or bits are arranged so that the field they emit is perpendicular to the medium, like this:
x . x . x . x
In the above diagram we're looking down at one track on the surface of a platter 'x' represents a field pointing away from us, '.' is one pointing towards us. This is what it looks like in cross-section (looking in from the edge of the platter):
^ | ^ | ^ | ^ | ^
| v | v | v | v |
In perpendicular recording the read head detects the actual direction of the fields emitted by these bits/magnets, rather than transitions in the field. Perpendicular recording is advantageous because it allows one to use a much smaller surface area on the medium for one bit. Imagine if you laid a line of bricks end-to-end on the ground, you could make the line shorter but taller if you stood each brick on end (so they're laid flat-to-flat), but you've not had to make the bricks any smaller in order to acheive this change in the length of your line.
Most of the above is hopefully right. Anyway it's a better explanation than that site gave.
Both schemes store the bit to some depth physically. You can't have an infinitely thin bit. Both schemes also still use a 2-D grid of bits. (Well, polar grid, since it's a spinning disc.)
A truly 3-D organization of bits within a single platter face would be something like those multi-layer DVDs, where within the same grid position you can access multiple bits by changing some aspect of the reading mechanism. (In the case of the DVDs, it's achieved by focusing the lense differently so only the desired layer is in-focus.)
--JoeProgram Intellivision!
Don't make fun of my floppy. I know it's small, but I use it alot. :(
Life is not for the lazy.
ASCII art is great for porn but for technical stuff I prefer real images. This image cleared things up for me.
What a poorly researched article. It is way below EEtimes quality and should have never been published as it is.
1. "As opposed to longitudinal recording, where the bits are impressed in a parallel format along the surface of a disc, perpendicular recording stands the bits on end, enabling more data storage per square inch."
What does it stand the bits at the end? I have never seend a standing bit. Especially on the end of it. Now c'mon, it could have been described a little more "technically". This is not USA Today.
And "impressed in parellel format" is such a crap of a phrase. It is not impressed, nothing touches, no impression, it is MAGNETIC, god damn!
2. "Apple Computer Inc.'s new G5 computers are all SATA-based while Intel systems will by the end of this year be based on the new interface."
Now this is utter turd. Before even G5 was announced, and probably before Jobs had the brainfart to invent them, some of the high-end PC motherboard manufacturers were already churning out SATA equipped motherboards. It was in the Intel development road map for several years now. I remember reading about it on Tom's 2 years ago.
Mr. Bolaji Ojo (EBN), please do your homework. Do not just blair (as in Jayson) out an article. You do wipe your ass after takin a sh*t, don't you? I am just asking that you would apply the same attitude toward writing articles. Thank you for your future cooperation.
Code poet, espresso fiend, starter upper.
Think of matchsticks flat on the floor and standing up. The ones standing up will be further apart, or you could pack more in the same floor area and have them the same distance apart.
The difficulty is, matchsticks have an easily distinguishable top and bottom end, but magnet ends are only distinguishable by the direction of flux. The bottom ends are buried in the media, so there are challenges in writing and reading the data because only one end of the magnet is accessible. Does this help?
Panurge has posted for the last time. Thanks for the positive moderations.
They also talked about drive sizes changes (3.5in -> 2.5in)
Bah, why always smaller???
Current HDDs store 50Gb/in^2, and area increases with the square of the radius. That single inch decrease results in literally half the platter area (not counting the spindle). OTOH, with even current areal densities we could have 1TB 5.25" HDDs. THAT would make me a happy consumer.
But no, that would make too much sense. Instead, they'll shrink the drive, requiring radical new (and untested in the wilds) technologies just to keep up with the same overall size.
Hey, I can appreciate smaller in most aspects of technology. But as long as we store data on spinning platters, where surface area matters, bigger, up to the width of a typical case (ie, 5.25in), makes a WHOLE lot more sense. Hell, use 10" platters and design the case around the HDD lying parallel to the MB for all I care, as long as I have obscene amounts of drive space.
Then again, I probably count as one of the few people who considered the Quantum Bigfoot series a great idea - Large, cheap, somewhat slower drives. For most uses, as long as a drive has a "reasonable" seek time and transfer rate (ie, within an order of magnitude of other modern drives), size matters more than speed. Most of us don't do realtime DV processing, we store tons of what amounts to largely offline content (ie, a huge CD changer would do just as well, other than for the drive we keep our OS on).
Well, in my experience, engineers only like to brag about a new technique if it gives a 10x improvement. (Or more.) If you read the article, you would have noticed some numbers:
:)
:)
The "brick wall" in magnetic recording is called the superparamagnetic effect. This is the point at which the recorded data starts to get lost in the thermal noise of the media. (As you approach the superparamagnetic, it becomes statistically likely for recorded bits to sporadically flip states resulting in data corruption.)
For longitudinal recording technology, it is estimated that superparamagnetic will start to become a problem around 100Gbits/square inch recording density. (Current hard drive technology is around 50Gbits/square inch - so they are getting close to the wall.)
Perpendicular recording technology is estimate to scale up to around 1Tbit/square inch.
Now, what did I say about engineers liking to brag about 10x improvements? Well, 1Tbit is about 10x improvement over 100Gbit. How about that!
What this means to you: if current hard drives store about 120GB using a recording density of about 50Gbit/square inch, then we can expect perpendicular recording to eventually deliver drives that store about 2.4TB extrapolating up to a 1Tbit/square inch. Even if this technology only works half as good, at least we will eventually have hard drives that store 1TB!
On top of that, the article say they are moving away from 3.5" drives toward 2.5" even for "enterprise" applications. Now, if we get 1TB drives in 2.5" form factor that's going to result in some killer MP3^^err...uncompressed 24bit, 192kHz iPods
PlaY tried it. Remember them? They had a really neat technology - not bigger than CD but much, much smaller. It was self contained so you could toss a dozen in your pocket like coins. It was actually this close to being a killer technology, then they got too close to the RIAA and DRM'd themselves out of existence.
Hard drives are decent enough backup. They're now cheap enough to justify keeping a second drive just to duplicate everything on the first. But copying even 80Gb of data still takes damn forever, especially if the drives are in different boxes (I mean, if you're going to make a backup, you do want that backup protected in case of a power suply glitch... right?)
But a pocket full of sealed discs is a lot more convenient and error resistant than a case of CDs. Then again, the next generation commodity RAM is supposed to be magnetic, so maybe we'll finally get that convenient, portable storage in the form of actual solid state "coins!"
Although the solution proposed in the article would increase storage capacity by, say, a factor 2 or 4, it still is a temporary solution that does not solve the fundamental problem at hand.
The fundamental problem is the superparamagnetic limit: if you make a magnetic domain (a bit) smaller than a certain size, it becomes thermodynamically unstable. In English, this means that very small bits loose their value after a while. It also means that for the time being, we'll have to use tricks to pack the bits closer together while keeping them large enough to be stable.
It should be noted that perpendicular recording is not the only effort to achieve higher recording densities in the looming shadow of the superparamagnetic limit. Indeed, harddrive manufacturers have seen this problem coming for a number of years now, and have had meeting to discuss possible solutions.
On a brighter note, there seems to be progress in circumventing the superparamagnetic limit: very recent research show promising results for the future.
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If I can't download anymore mp3s why do I need more storage?
"It's so convenient to have a system where everyone is a criminal" - A. Hitler
Historical Note: This "new" recording technique is the same one that failed to take hold in 2.88M EHD floppy disks about 15 years ago. Back then the new recording material was barium ferrite, whose magnetic domains arrange themselves vertically with respect to the substrate.
Compared to ordinary floppy disks with horizontal magnetic domains, this technology had the potential of increasing data densities by as much as 2-3 orders of magnitude. Unfortunately, the new disks were expensive and not compatible with the huge installed base of 1.44M drives. EHD drives required BIOS changes that weren't possible in those non-FlashBIOS days. Even if those problems could have been solved, IOMEGA's Zip drives were offering far more bang for the buck.
Of course, none of this would matter for hard drives.
It'd be more like:
from --------
to ||||||||
Perpendicular recording would effectively replace a two-dimensional bit with a one-dimensional bit, from the recording head's point of view. (Or something close to that.)
I'd have a personalized plate on my car, but "toxic bachelor" won't fit into 7 letters.
If you look at a 1 or a 0 from the side, they're pretty big. But if you look at a 1 or a 0 from the top, they're a lot smaller! I guess a 1 will look like a dot, and a 0 will look like a line. That must be pretty easy to do, right? Pure genius!
The rotational speed of the drive is directly related to the access time. If the data you want is on the other side of the platter, you must wait for it to rotate 180 degrees before you can start reading, regardless of whether the disc is 1/2" in diameter or 2" diameter, whether there are 1GB per square inch or 10GB per square inch.
When the head gets lined up with the track and ready to read, the data it's waiting for can be anywhere between 0 degrees and 360 degrees away. If you average out all those possibilities, you can expect the data to be about 180 degrees away.
Now, a 15000 rpm drive rotates 180 degrees 30000 times per minute. Conversely, it takes 2ms to rotate 180 degrees. If you consider that a typical 15k rpm drive has an average seek time of 3.3ms and we know that 2ms are spent waiting for the disk to spin, than 1.3ms must be spent moving the head. This proves to me that rotational speed is more important to access time than data density.
I'm no hard drive engineer, but I would bet that an increase in density would mean a decrease for rotational speed since a read head probably has a limited bandwidth. (This is probably why the faster-spinning drives typically hold less data.) If you halve the time moving the head while doubling the time waiting for spinning data, you will see an overall increase in seek time.
My conclusion is that greater density and less rpms would hurt access time which is the most important performance factor. However, like the "MHz myth", I'm sure marketing will focus on bandwidth benchmarks for performance instead of real-life application performance.
So, a top view of the old scheme would look like:
::::::::
::::::::
..1....0....1....1....0..
||||||||
||||||||
The new scheme, from the top:
In this case 2x density, as the lower one has twice as many dots in the same area as the dashes of the upper.
I don't think that's quite right.
Unless I missed a transition from longitudinal to transverse recording, the old scheme produced a track like this (viewed either from the top or side:)
N---SS---NN--------SS---N
The vertical scheme lays the magnets INTO the medium rather than ALONG the track. Viewed from the side:
NSNNS
|||||
SNSSN
10110
Or, viewed from the top:
NSNNS
The problem with longitudinal recording is that, as you make the bits shorter, the magnetic fields of adjacent opposite-sense bits become more effective at trying to flip the singleton to go along with them. (Magnetic domains are more self-reenforcing, and thus stable, when they're long and thin, subject to flipping from thermal agitation at progressively lower temperatures as they become more short and fat.)
Make the bit too short and the neighbors "squeeze it out":
N--SSNN--S -> N--------S
1.1.0.1.1. -> 1.1.1.1.1.
But with vertical recording the adjacent, opposite-sense neighbors tend to STABILIZE the bit, and the smaller it gets, the more stable it gets. (And you're guaranteed a limit on the number of long runs of same-sense by the coding scheme, which has to flip now and then to keep the read electronics in sync.)
So you can shrink it WAY down - both along the track and across it - to the limit of the head technology to produce the original magnitizing field or the inherent domain size of the magnetic medium.
You can get FAR more than a factor of two in EACH direction - and multiply the two improvements to get the increase in bits per unit area.
(They've been talking about this for years. How come it's just hitting the field now? Did they go to transverse magnetization in the meantime? That would have similar advantages of smaller-is-more-stable. But the track would be far wider than with vertical, as would the gap, so you'd still save a bunch in one of the dimensions by standing the magnets on their head and packing them in tightly, like a bundle of sticks, rather than laying them on their sides.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way