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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
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?
In the days of 250GB hard drives, who cares? All I'm concerned about is the speed of drives. Lets improve that for once...
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.)
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...
With perpendicular recording the bar magnet would be standing on it's end.
Longitudianl recording is like this:
Perpendicular recording is like this: Google is your friend...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.
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.