How Heat-Assisted Magnetic Recording works
We recently wrote about the need for storage media with greater storage
capacities – focusing on Shingled Magnetic Recording (SMR) techniques and
how this results in HDDs that are capable of storing more data within standard
formats. Today, we discuss another means of achieving this: Heat-Assisted
Magnetic Recording (HAMR).
Like Shingled Magnetic Recording, HAMR increases a hard drive’s storage
density by increasing the amount of data each of its platters can hold. Whilst
Shingled Magnetic Recording achieves this by allowing data tracks to overlap
with one another, though, HAMR does it by decreasing the physical space needed
to store each individual byte, thus increasing the amount of data the platter
can store. Best of all, it does this by using lasers (we’re geeks at Fields Data Recovery and geeks love
all things laser-related.
When the HAMR technique is utilised, a laser heats the surface of the
drive’s platter whilst data is being written to it. This makes the material
more receptive to magnetism meaning that less space is needed to store each
byte. What’s particularly impressive is that the heating, cooling and writing
process is completed is less than a nanosecond – and it was achieving this
within such a small timeframe that was always the biggest problem engineers
developing this writing technique faced. It was so significant a challenge, in
fact, that a solution has been more than 50 years in the making.
HAMR isn’t exactly new
A patent outlining the basic process of using heat and magnetic fields
in order to store data was filed in 1954. A now obsolete form of storage media
known as the magneto-optical drive used a rudimentary form of HAMR in the
1980s. You may even remember Sony’s MiniDiscs; they were designed to replace
cassette tapes and, just like the aforementioned magneto-optical drive, are now
an obsolete piece of technology that made use of the HAMR writing technique.
All in all, it wouldn’t have been a surprise if researchers had given up on it
altogether. Indeed, at the time of writing, you cannot actually buy a HDD that
uses HAMR technology for residential or commercial use – but that could soon
change.
Reasons to be excited about HAMR
Seagate have, following more than a decade of research and development,
begun manufacturing HAMR drives and began trialling them with selected
companies in the latter half of 2017. The company have also stated that they
have already built in excess of 40,000 HAMR drives as well as a significant
number of HAMR read/write heads. Most importantly, they have also claimed that
they will begin shipping HAMR drives with capacities of greater than 20TBs in
2019.
The hard drive manufacturers have further estimated that they will be
offering HAMR drives offering 40TB capacities in just five year’s time and that
100TB capacities will be available by 2030.
With the exception of DNA
data storage – which still has a number of technical hurdles before it can
be considered even a practicable cold storage solution – this represents that
biggest potential improvement in storage densities currently in
development.