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.