The evolution of data storage technology has been marked by a relentless search for greater capacity and efficiency: perpendicular recording (PMR), helium-filled drives, tiled magnetic recording (SMR) are some examples.
Among the most promising innovations in the field of hard drives is HAMR technology - Heat-Assisted Magnetic Recording (pronounced "hammer"). This technology promises to transform traditional magnetic storage, offering solutions to some of the biggest challenges faced by modern hard drives.
In this article, we will explore what HAMR technology is, how it works, its advantages and challenges, and its potential impact on the future of data storage.
The Context of Magnetic Storage
Hard disk drives, or HDDs, have been a fundamental part of computing since their invention in the 1950s. These devices use magnetic recording to store data, with information encoded on magnetic tracks on spinning disks. However, as demand for greater storage capacity and faster read/write speeds has increased, HDD manufacturers have faced physical and technological limits with traditional magnetic recording techniques.
The Need for Innovation
Over time, the storage density of hard drives has been steadily increasing. This increase has been limited by the capacity of current magnetic recording methods. Perpendicular Magnetic Recording (PMR) technology has enabled significant advances, but the demand for more capacity has led to the need for new approaches. The answer to this challenge is HAMR technology, which promises to revolutionize magnetic storage.
What is HAMR Technology?
HAMR (Heat Assisted Magnetic Recording) is an innovative technology designed to increase storage density on hard drives. The main idea behind HAMR is to utilize a recording method that involves locally heating magnetic media to improve storage capacity. Below, we explore how this technology works and the principles behind it.
How does HAMR work?
• Localized Heating: HAMR technology uses a small device called a “heating laser” to locally heat the area of the hard drive surface where data will be written. This temporary heating reduces the coercivity of the magnetic material, making it easier to write information at a much higher density.
• Advanced Magnetic Material: The magnetic material used in HAMR hard drives is designed to withstand high temperatures and quickly return to its original state after cooling. This material is known as "high coercivity magnetic material," which is essential to ensuring the stability of stored data after the recording process.
• Recording and Reading Data: During recording, the heated area of the disk is magnetized to represent the data. Once the area cools, the information is fixed on the magnetic media. This allows data to be stored at a much higher density than with traditional methods.
• Precise Temperature Control: Accurate temperature control is crucial for the operation of HAMR. The laser needs to be extremely precise to ensure that only the desired area is heated without affecting neighboring areas, which poses a significant technical challenge.
Coercivity is the ability of a magnetic material to maintain its internal magnets in a specific position. This position can be changed if the magnetized material is placed in an external magnetic field. A material with high coercivity indicates that its internal magnets are very resistant to changes in position, requiring a stronger external magnetic field to be demagnetized.
The coercivity of many materials depends on temperature. If the temperature of a magnetized object is temporarily raised above the Curie temperature, its coercivity will decrease greatly until it cools. (This can be seen by heating a magnetized object, such as a needle in a flame: by the time the object cools, it will have lost much of its magnetization.)
HAMR uses this property of magnetic materials to its advantage. A small laser in the read/write head temporarily heats the area being written to, so that it briefly reaches a temperature where the disk material temporarily loses much of its coercivity.
Nanoscale recording technologies - Image Credit: Disclosure
Almost immediately, the magnetic head writes the data to a much smaller area than would otherwise be possible. The material cools again rapidly, and its coercivity returns to prevent the recorded data from being easily altered until it is written again. Since only a small part of the disk is heated at a time, the heated part cools quickly (less than 1 nanosecond) and comparatively little power is required.
The regions being written must be heated in a small area and require a heating, writing, and cooling cycle of less than 1 nanosecond, while controlling the effects of repeated spot heating on the drive platters, the read/write heads, and adjacent magnetic data.
These challenges required the development of nanoscale surface plasmons (surface-guided lasers) instead of direct laser-based heating, new types of glass platters and heat control coatings that tolerate rapid heating without affecting contact with the recording head or nearby data, new methods for mounting the heating laser on the drive head, and a wide range of other technical, development, and control issues that needed to be overcome.
Traditional coated magnetic platters were also not suitable due to their heat conduction properties, so new drive materials needed to be developed. Seagate Technology and Showa Denko (SDK) use an iron-platinum (FePt) alloy in glass platters for HAMR drives.
The Future of HAMR Technology
Impact on the Storage Market
HAMR technology is expected to have a significant impact on the storage market. The increased capacity and improved performance of HAMR hard drives can lead to greater efficiency in data centers and cloud storage systems. In addition, higher storage density will enable businesses and individuals to store more data in less space, which could transform the way we manage and use data.
Impact on Data Centers - 187 Exabytes in the same space as 100 Exabytes - Image Credit: Disclosure
Seagate is offering the Mozaic 3+ (still with limited availability) with 32TB (with SMR technology) and 30TB (with CMR technology) with HAMR technology and featuring a capacity of 3TB/disk (platter).
The company is planning 4TB/platter drives in the next few years, with 5TB/platter coming soon after.
Conclusion
Heat-Assisted Magnetic Recording (HAMR) technology represents a significant breakthrough in magnetic storage. With the ability to increase storage density and improve the performance of hard drives, HAMR has the potential to transform the way we store and manage data. Despite the challenges and costs associated with implementation, continued advancements and investment in research indicate that HAMR could become a critical technology in the future of data storage.
As technology evolves and overcomes current obstacles, HAMR can redefine industry standards and open up new possibilities for storing large volumes of data. The future of data storage is undoubtedly exciting and full of potential, with HAMR playing an important role in that journey.
