Researchers at the National Physical Laboratory in Teddington, UK are working on a new hard drive read head which would be 5 to 10 times faster than heads used in hard drives today:
The design, published in the Journal of Applied Physics, is based on a different magnetic effect than current read heads. It could lead to much thinner and smaller read heads that are suitable for data densities as high as one terabit per square inch, says lead researcher Marian Vopsaroiu.
The new sensor would also use slightly less power than current read heads--an especially useful feature for laptops and MP3 players. And it could improve the speed of the reader. "You could read back data ten times faster," Vopsaroiu says. "Instead of one GHz, you can read at five to ten GHz."
Laptops and computers currently use the magneto-resistance effect to read hard-disk data. Hard disks store bits magnetically; depending on the direction of a bit's magnetic field, it can represent a bit 1 or 0. As the read head flies over the disk, the magnetic fields of the bits cause a corresponding resistance change in the read head's sensor. The resistance can't be measured directly, so it's first converted into a voltage using a direct current. (The voltage is equal to the current multiplied by the resistance.) In order for the whole thing to work, a current must run continuously through the sensor.