What is an EAMR Hard Drive? – What You Need to Know about Modern Storage
When first made, hard drives, or rather, storage devices, were the size of a room. As years went by, storage devices changed shape as well as size, until we reached a couple of standardized formats, namely 3.5 and 2.5 inch hard drives, the former often used for large storage sizes.
However, traditional technologies such as shingled magnetic recording (SMR) and perpendicular magnetic recording (PMR), while improving upon the previous longitudinal magnetic recording’s (LMR) size limits, have reached their own size limit.
Hard drives are still the go-to purchase when it comes to storage size, particularly when put against SSDs. To surpass the limits of the nowadays widely used PMR, companies like Western Digital, Seagate and Toshiba have turned towards energy-assisted magnetic recording or EAMR.
What is EAMR and How Does it Help Increase Storage Size?
PMR uses two layers of magnetic platters, a recording layer, where the bits are actually stored and an additional layer, which can be thought of as a part of the write head, even though it is beneath the recording layer.
This additional layer is used to guide the magnetic flux in a perpendicular arrangement.
However, even PMR has a similar areal density (the amount of data which can be stored in a platter of a given size) as technologies prior to it, hence the need for EAMR.
EAMR – Storage Size Increase Through Magnetic Manipulation
Coercivity (the ability of a material to maintain magnetic properties and resist external influence) is the main problem for storing data reliably in small bit sizes. To store data in a small and dense way, high coercivity is necessary. But then, the write head cannot overcome the coercivity or rather, flip the magnetic domain (to write a 0 or a 1).
This is where the energy-assisted part comes into play, using either heat or microwaves to change the tiny spot’s temperature past its Curie point (above which it would lose its magnetic properties until cooled down).
HAMR – Heat Assisted Magnetic Recording
HAMR is one of the ways to change the coercivity of a very small spot where the data would be written. In this case, a small laser would heat the point where data should be written, upon which the write head would immediately write the data. The spot would cool off, its coercivity returning to its previous state, making the data stored safe until another write is required.
This would happen in the duration of a nanosecond, making the process energy efficient as well.
Traditional plated magnetic platters cannot be used due to their magnetic properties in regards to heating, meaning new materials need to be used.MAMR – Microwave-Assisted Magnetic Recording
MAMR is similar to HAMR, but instead of heat, microwave frequencies of 20-40 GHz are used to lower the platter’s coercivity, allowing for the bit to be changed and the data written. These two technologies achieve a similar result but use different means of lowering the platter’s coercivity.
It is worth noting that these technologies can only work on magnetic (hard drives) and that even the best SSDs will not be able to achieve the proposed storage sizes in commercially available drives in the coming years.
Summary and Conclusion – The Future of Storage
Hard drives are essential to large storage sizes and price to performance. Traditional recording technologies have reached their limits in terms of areal density. Energy-assisted magnetic recording or EAMR and the technologies which fall under its wing, HAMR and MAMR, will expand storage density and size, bringing huge capacity to commercial and enterprise drives.
Some of these technologies will eventually trickle down to consumer drives, possibly even making good gaming hard drives a lot better (with more capacity).
The future will include improvements on EAMR like heated dot magnetic recording (HDMR, a direct advancement of HAMR) and bit-pattern recording (BPR), both of which will increase storage density.