Shingled Magnetic Recording explained

Last week, we wrote about Western Digital’s latest HDD and the fact that, by utilising a unique way of writing data known as Shingled Magnetic Recording, it boasts the greatest storage capacity of any HDD in history – but how does this new writing technique work and, more importantly, why does it result in superior storage densities.

All HDDs write data onto discs coated in magnetic materials, commonly referred to as platters. All data is comprised of individual bytes which represent either a one or a zero. This means that, when you choose to store data on a HDD, it is translated into a series of ones and zeroes and written onto the platter with each one or zero taking up one bytes worth of space. These ones and zeroes are written onto platters in a continuous circular pattern, known as tracks, wherever possible. When Shingled Magnetic Recording is used, new tracks slightly overlap with older tracks which, in turn, means that more tracks can be stored on each platter, increasing the drives overall storage density. These tracks are said to resemble the overlapping shingles commonly seen on the roofs of residential properties, providing this technique with its name.

Why Shingled Magnetic Recording matters

With the vast majority of new devices sold with flash-based storage such as SSDs already installed, you may be wondering why manufacturers are developing new technology for HDDs, but the answer is relatively straightforward: we’re running out of storage space for data.

The simple fact is that we’re creating data at a truly exponential rate. So much so that experts predict that that total amount of data stored worldwide grows by 100% every two years. Worse yet, they suspect that demand will be outstripping supply within less than a decade. In short, we need storage media that can store more data within existing forms, hence the reason why higher-capacity HDDs are so important.

Granted, we’ve alluded to the fact that they’re unlikely to be used on off-the-shelf PCs, laptops etc. but by simply improving their largest HDD’s capacity by 1TB, Western Digital have provided data centres with a device that they can use to significantly ramp up their capacities.

Still, advancing and bettering the capacity of HDDs is unlikely to prove to be a long-term solution (DNA data storage is seen as the most likely answer to this conundrum) but, for the moment, short-term solutions are what’s needed and Shingled Magnetic Recording is a technique that, for the time-being, provides us with what we need.