California based data-storage Company HGST has begun making a six-terabyte helium hard drive that has a 50 percent greater storage capacity and uses about 20 percent less power than conventional hard drives. The secret to this leap forward in performance? Pumping the drives full of helium. Helium reduces friction, vibration, and other mechanical issues that limit the storage density of conventional hard drives. Helium-filled hard drives could be appealing to data centres and businesses like banks and insurance companies that handle vast amounts of information.
Stacked inside a hard drive are magnetically patterned platters, each of which has an arm suspended over its surface. A read-write head hovers over the platter very close but without touching—about a nanometre away—using a magnetic field to read and write information. As the platters in a hard drive start to move, the air surrounding the disk’s surface also begins to rotate. A hard-drive disk spinning in air meets resistance and tends to flutter, putting strain on the motor, requiring more power.
The advantage of laying the tracks down in this fashion is that you pack data more closely together. The disadvantage is that rewriting tracks will damage the data on subsequent tracks. This can lead to huge write amplification — if a 4KB update needs to be performed to a 64MB area of track, then the entire 64MB has to be read into RAM and laid back down with the modified 4K section. To reduce the impact of this write amplification, the drives are divided into bands — contiguous blocks of data that are treated as a unit.
It’s important to avoid random reads and writes as much as possible when using SMR, however, which is why HGST is marketing these drives as “cool” to “cold” storage — meaning data that’s written very few times and accessed only on occasion. If the drive is being regularly written and re-written, the performance penalties will quickly become severe. The HGST drives also require extensive modification and drive software in order to operate properly. Read here in details about the benefits of using helium filled hard drives.