For about the past decade, scientists and engineers have pondered the potential effects of a natural phenomenon called superparamagnetism and postulated when its presence might interfere with the progress of the hard-disk drive, or HDD, industry.
Since the first commercial hard drive was introduced, in 1956, the industry has grown storage capacity exponentially by decreasing the size of the magnetic grains that make up data bits. In effect, the smaller the magnetic grain, the smaller the bit, the more data that can be stored on a disk. With longitudinal recording, we are getting close to the point where data integrity will be harmed if we continue to shrink the magnetic grains. This is due to the superparamagnetic effect.
Superparamagnetism occurs when the microscopic magnetic grains on the disk become so tiny that random thermal vibrations at room temperature cause them to lose their ability to hold their magnetic orientations. What results are "flipped bits"?-bits whose magnetic north and south poles suddenly and spontaneously reverse?-that corrupt data, rendering it and the storage device unreliable.
Today, the hard-drive industry?s ability to push out the superparamagnetic limit is more critical than ever as capacity requirements continue to grow dramatically. This is due, in large part, to the increasing use of hard drives in consumer electronic devices and the desire to pack more and more storage capacity on smaller devices. The superparamagnetic effect on current magnetic recording technologies will make that growth impossible within one-to-two years.
Thanks to renewed interest in a magnetic recording method first demonstrated more than 100 years ago, there's confidence in the storage industry that the natural effects of superparamagnetism can be further stalled. That method is called perpendicular recording, which, when fully realized over the next five-to-seven years, is expected to enable a tenfold increase in storage capacity over today's technology. This would, for example, enable production of a 60GB 1-inch microdrive--a higher-capacity version of the microdrives used in MP3 players, personal media players, digital cameras, PDAs and other handheld devices.
To help understand how perpendicular recording works, think of the bits as small bar magnets.
In conventional longitudinal recording, the magnets representing the bits are lined up end-to-end along circular tracks in the plane of the disk. If you consider the highest-density bit pattern of alternating 1s and 0s, then the adjacent magnets end up head-to-head (north pole-to-north pole) and tail-to-tail (south pole-to-south pole). In this scenario, they want to repel each other, making them unstable against thermal fluctuations.
In perpendicular recording, the tiny magnets are standing up and down. Adjacent alternating bits stand with north pole next to south pole; thus, they want to attract each other, are more stable and can be
Biography
Jun Naruse is CEO of Hitachi Global Storage Technologies Inc.
See more CNET content tagged:
pole, magnet, grain, storage capacity, microdrive
http://www.hitachigst.com/hdd/research/recording_head/pr/PerpendicularAnimation.html
- IBM Had This 40 Years Ago
- by Stating May 12, 2005 5:51 PM PDT
- Everything old is new again. A number of IBM disk drive models back in the 60's supported cylinder recording (perpendicular). Data was written across multiple platters simultaneously, top to bottom then left to right to reduce rotational delay.
- Like this Reply to this comment
-
-
- You mis-understand completely....
- by May 14, 2005 1:56 AM PDT
- Perpendicular recording has nothing to do with how multiple heads search for the data over multiple disks. It is the fundemental way that the data is magnetically stored on the disk. Imagine it this way.... Think of a bunch of people laying down within one lane of a running track (the HDD disk). Imagine that your job is to go along the line of people and note the orientation of each person's head/feet (the HDD head). So you are going along counting "head, feet, feet, head, feet, head, head, feet" (in HDD terms - positive, negative, negative, positive....).
- Like this
-
- This is not the same
- by May 16, 2005 3:44 PM PDT
- This is not the same as the old IBM technology, this is actually affecting the way the bits are arranged on a single platter. instead of a byte being arranged like so -------- it will now be arranged like ||||||||.
- Like this
-
(6 Comments)http://www.ibm1130.net/functional/DiskStorage.html
Data Organization
The disk access mechanism, located in the disk drive, is moved back and forth by programmed commands and can be placed in any one of 203 positions, from a point near the periphery of the disk to a point near the center of the disk. At each position, the heads can read or write in a circular pattern on both surfaces of the disk, as it revolves. The circular patterns of data are called tracks. The track on the upper surface of the disk and the corresponding track on the lower surface, both of which can be read or written while the access mechanism is in the same position, are called a cylinder.
Keith
www.techcando.com
Now, let's say you want to add more people to that given track lane (increase HDD areal density). So you tell everyone to move closer to each other - move your feet closer to the next person's head. Well, you can only scrunch everyone so close together until feet start overlapping heads, and you are no longer able to quickly walk by and count head/feet order (HDD data integrity loss).
So you think, hmmmm....if I got everyone to stand up instead of laying down (perpendicular), then I just have to count who are standing on their heads and who are doing handstands.
OK, my analogy starts to get a little silly here, but you get the idea. Hope this helps. And yeah, I'm in the HDD industry.