Data recording technologies are improving, HDD capacity is growing
Over the past couple of years, more than once or twice, I have heard the opinion that HDDs will soon give way to solid-state drives. They are becoming more capacious and faster, and their prices are falling. But everything is not so simple, since technologies in the HDD world also do not stand still, but continue to develop. Recently it became known about a new achievement of developers from Seagate and scientists from Tohoku University. Details are under the cut.
What has been achieved in data recording technology?
Joint team from the National Institute of Materials Science (NIMS), Seagate Technology and Tohoku University conducted a successful experiment on multi-level data recording using three-dimensional magnetic “information packaging”. The experiment used platter heating, which in general is not a new product, but in combination with other methods it makes it possible to increase the HDD capacity to 60 TB right now. It may well be that in a few years, hard drives with a capacity of 120 TB will appear. So it’s too early to retire HDDs; this type of drive will clearly begin to develop in the near foreseeable future.
The concept of multi-level magnetic recording for hard drives has been around for some time, but its practical application has been hampered by the lack of suitable substances capable of storing data at different levels. The researchers solved this problem by creating a new type of coating consisting of two FePt-C nanogranular iron-platinum films separated by an intermediate Ru-C layer with a cubic crystal structure. This allows for separate recording on each layer in different magnetic fields and temperatures.
By adjusting the laser power and characteristics, the configuration of the magnetic fields during the writing process, each of the FePt layers can be written independently, potentially doubling the recording density and capacity of the hard drive without significant changes in the materials of the magnetic layers. Researchers say such media can provide storage densities of more than 10 terabits/inch², i.e. hard drives with 10 platters and a capacity of more than 120 TB.
In the near future the project team going to develop a technology to reduce the grain size of the coating of disk plates, optimize work with magnetic fields, and also increase the number of layers of FePt film to create a data carrier structure that can function not only in the laboratory, but also in real conditions.
HAMR technology – what is it?
It is clear that HAMR is an abbreviation; it stands for Heat-assisted magnetic recording (“thermomagnetic recording”). The technology allows you to achieve a recording density of 2.32–7.75 Tbit/cm². According to American tech journalists who love comparisons, on just one 37 TB disk it will be possible to record all the materials of the US Library of Congress in uncompressed form.
The essence of the technology is local heating by a laser and magnetization reversal during the recording process of the surface of the hard disk platters. The laser built into the HDD head allows you to heat the coating of the “pancake” up to 500 degrees Celsius. Accordingly, the desired area is magnetized even with a relatively weak magnet in order to record data. The developers of the technology report that this does not change either the physical or chemical properties of the plate. But the capacity – yes, it can be significantly increased, and after cooling the platter, the data is not lost, they are read without any problems.
The technology itself is far from new; it has been developed at Seagate since 1998, and an entire division called Seagate Research is engaged in this work. In 2018, i.e. 5 years ago, the first 16 TB hard drive developed using HAMR technology was released. And now, as we see, it is gradually improving.
What else?
Seagate continues to create new, more advanced HDDs using other technologies. In particular, SMR and PMR, which makes it possible to produce high-capacity HDDs without the need to heat the platter with lasers. As for SMR, this technology is called “tiled recording”. Thanks to it, the recording density on the platter is about 1,248 Gbit/inch².
In this case, the recording process can be controlled in two ways. The first is with the use of a disk controller. The second is using the software of the system to which the drive is connected. Seagate HDDs belong to the second type. Their maximum capacity is 24 TB, but it is quite possible that SMR HDDs of larger capacity will appear in the near future.
PMR is a perpendicular magnetic recording technology that allows data to be placed on parallel tracks. True, discs made using this technology seem to have reached a technological limit. Not so long ago, Seagate, having released a 24 TB HDD, stated that for PMR technology this is almost the maximum, so further work in this direction makes no sense.
As far as one can judge, in the near future the density of data recording on HDDs will increase, and the capacity of the hard drives themselves will increase. So, it is likely that SSDs will not begin to replace HDDs very soon: the capabilities of the latter have not been exhausted.
