How much Data can be Stored in so Small a Drive?

Last month, the Millennium Technology Prize for 2014 was awarded to Prof. Stuart Parkin of International Business Machines Corporation (IBM) for his work on disk drive storage technology. The Millennium Technology Prize is awarded every two years to scientists who have made technological inventions that on a global scale have improved people's lives or have the prospects of doing so. And the award of this year's Prize to disk storage technology evoked in me the question of how much data can be stored in the smallest of a single drive and the expectation of more groundbreaking storage technologies in the future.

Prof. Parkin giving a speech at
the Award Ceremony. Image credit to Xinhuanet

Computer processors are getting smaller and faster each year-something that aligns with the so-called Moore's Law which predict that processors in computers will become smaller as they get faster; and this has applied for over four decades: we have supercomputer nanoprocessors doing hundreds of millions and billions of computations that totally dwarf their size today, unlike what was obtained back in the 1950s when computers and hard drives with memory capacity of 1 megabyte could take the space of a whole bedroom.
 
While the Moore's Law has held over the years for computers, I think an analogy of it has also been in motion over the years in the area of data acquisition and storage technology. Storage technology has got smarter over the years, with disk drives reducing drastically in size while their capacity to store data increases exponentially. This was made possible because of the fundamental works that have been done and leveraged on in the field of electromagnetic and quantum physics.

In the early years of the 20th century, scientists discovered that they can harness the charges of electrons in a magnetic field to store bits of information (bit is the smallest unit of information that can be stored; and 8 bits are equal to 1 byte). This means that information is stored in a disk drive as tiny magnetic regions in a magnetic film and read by converting the magnetic change (information signals-audio and video) in the film into electrical current (depends on electron charge). While a lot of information could potentially be stored in these tiny magnetic regions in the magnetic film of disk drives, that did not happen because writing and reading vast amount of data on small disk drives posed a challenge: these tiny magnetic regions got weaker as the size of the hard disk drives reduced requiring very sensitive reading device to read them, especially at room temperature.

L-R: Profs. Albert Fert and Peter Grunberg
at Nobel Prize Interview. Image credit Nobel Prize

GMR structure. Image credit to
Magnet Lab

But as much insight was being gained in the area of quantum mechanics, scientists began to explore additional, miniature, properties of the electron such as its spin property when there is a change in direction of a magnetic field. In 1988, Albert Fert and Peter Grunberg independently and simultaneously discovered what is known as Giant MagnetoResistance (GMR), in which there is a profound change in electrical resistance in a thin film structure made of several layers of ferromagnetic and non-magnetic conductive materials (Professors Albert Fert and Peter Grunberg who won the 2007 Nobel Prize in Physics for the discovery of Giant
 MagnetoResistance); this phenomenon was immediately found to be very useful in the area of hard disk drives and biosensors, as the very tiny magnetic changes in tiny magnetic regions where information is stored can cause significant change in electrical resistance in any GMR structure it comes into contact with.

Spin-valve sensor. Image credit to
Wikipedia

This was where Professor Stuart Parkin came in. By the early 1990s, while working at IBM, he found a way to manipulate the spin-up and spin-down property of the electrons in the Giant MagnetoResistance sensor depending on the magnetic field direction of its multilayered materials to generate a spin-polarized current that could be turned on or off. This allowed him to design a type of valve that served as a read-out head ( a device that detects audio or video signals or any other data (by converting the weak magnetic regions into electrical current via large changes in electrical resistance in the GMR part of the valve) when flown over the magnetic films of hard disk drives), thus allowing for far greater amount of data to be written to and stored in hard disk drives than was possible before the invention. The spin-valve sensor was used to build the first 16 GB hard drive by IBM in 1997; and today the technology has allowed the design of hard disk drives with up to 6 Terabytes storage capacity.

Google's Data Center in Hamina, Finland.
Image credit to Financial Post.

Professor Parkin's research opened up a new branch in quantum physics called Spintronics which explores how the spin of electrons could be harnessed and applied in different areas in the  field of computing which will in turn have virtually limitless applications in any area of human endeavour that requires technology--and in this age we are in every human endeavour has something to do with technology to witness rapid transformation. His spin-valve sensor has undergone several modifications to make it much better and adaptive to the computing demands of today's processes. Companies like Google, Facebook, iTunes and Amazon whose services (searches, streaming music and videos online, looking for friends, shopping online) respond with several possible options even before we completed the clicks would not have been what they are today
without Professor Parkin's spin-valve technology because these highly personalized services depend on mined data on consumers' (you and I) behaviour when online, and which need to be stored for processing and profiling--and these companies have huge data storage centres with thousands of hard disk drives with the spin-valve technology.

A micro hard drive.
Image credit to IBM

Many other entities such as telecommunication companies, which store consumers' call data for a period of time; website hosting companies and so on also depend on the spin-valve technology for huge data storage capacity. As well, national security organisations such as the US National Security Agency (NSA) which mine and store data on people's and organisations' calls, text messages, emails, Skype calls, internet searches, credit card information, financial records and so on for security profiling AND SO ON depend on Parkin's innovation. In fact, the NSA recently commissioned a one million square-foot data centre in Utah called Bumblehive which has a data storage capacity of one yottabyte which is equal to one thousand trillion gigabyte.

But one million square feet is a huge land space just for data storage considering the ever growing housing demand, achieving environmental efficiency and much more. Can this one yottabyte storage capacity be squeezed into a smaller space? There is hope I suppose as IBM and other groups are working to pack more data in a smaller drive. Scientists at the Agency for Science, Technology and Research, Singapore are simulating models of what they call single grain-based magnetic recording and storage. Current hard drives store information (one bit) in magnetic regions which are like aggregates of grains in a magnetic film; but their model aims to store each bit of information in one grain instead of multiple grains. This would increase the storage capacity, according to their estimates, to 10 terabytes per square inch. If achieved, there would be hard disk drives of up to 15 Terabytes in storage capacity. This means an increase in the size of current cloud-based services offered by companies like Dropbox, Microsoft (SkyDrive) and Google (Drive) at the same or even lower price; the price of other services like web hosting will also significantly reduce, meaning businesses, especially those in the developing parts of the world will flourish as the cost of maintaining an online presence falls. And as Professor Parkin's continues to make further improvement to this groundbreaking innovation of his-- the latest being what he calls Racetrack memory in which he is working to exploit spintronics to create a new type of storage that will consume less energy and still be able to store as much data as magnetic disk drives--many more attendant waves of benefits are expected to cause ripples across the large waters of human growth and development in the nearest future of storage technology