In April 2006 Seagate began shipping the first 3.5" desktop hard drive
using Perpendicular Magnetic Recording (PMR) technology and since then PMR has
become essential in allowing all of the hard drive manufacturers to create the
2 TB+ drives available today. As we approach the limits of what drive
manufacturers are able to do using PMR alone; however, they are starting to
look at additional technologies to boost the storage density. One such
technology on the horizon is Heat Assisted Magnetic Recording, or HAMR.
According to a recent
press release, Seagate is not only experimenting with HAMR but is the first
drive manufacturer to use HAMR to reach 1 Terabit per square in of areal
HAMR works by using a laser to heat up the storage medium before the
compounds used to store data have their orientation aligned by the write heads
of the drive. As bits get smaller and smaller, traditional magnetic recording
methods are not strong enough to permanently change the magnetic orientation of
the bits, which means that there is an inherent, if theoretical, minimum bit
size and corresponding maximum storage density possible with current
Perpendicular Magnetic Recording. HAMR further allows drive makers to get
around that limitation by heating the physical bits to the point that
traditional magnetic write heads can change the orientation.
he current 1 Terabit per square inch achieved using HAMR is also the
theoretical maximum storage density for PMR alone (as mentioned above), which
is promising as it implies HAMR still has a lot of working room to improve and
has matched the maximum proposed for PMR.
Seagate expects to use HAMR to produce 60 TB+ 3.5" and 20 TB+ 2.5"
hard drives within the next ten years. To put this areal density in
perspective, current 3 TB desktop drives feature approximately 620 Gigabits per
square inch while current 750 GB laptop (2.5") drives feature about 500
Gigabits per square inch. Interestingly, when comparing the 1 Tb/in^2
mechanical drive density to flash (ie SSD) storage at equivalent densities, it
works out such that a single bit equals 1nm of flash storage!
Unfortunately, we won't be seeing 60 TB drives any time soon. Rather,
Seagate expects 6 TB desktop drives and 2 TB laptop drives to be the most
immediate benefits of the heat assisted recording technology. Still, as my 2 TB
drive is filling up more quickly than I ever imagined (thanks to working with
HD video and making regular backups of data), I welcome as much increased
storage as I can get!