In July 2020, Western Digital announced new EAMR hard drives. What are EAMR disks and how do they work?
What is an EAMR hard drive and how does it work?
© Western Digital
The technology of a magnetic hard disk is so old and natural that there are hardly any real innovations. But data centers are still looking for hard drives with the largest possible storage capacity. For this reason, Western Digital (WD) has developed new drives especially for companies that contain the so-called “ePMR” technology (Energy-Assisted Perpendicular Magnetic Recording). For the sake of simplicity, however, we will stick to the term “energy-assisted magnetic recording”, or EAMR for short.
In July 2020, Western Digital announced new hard drives of this type, including 16 TB and 18 TB Gold series models and a whopping 20 TB drive from the Ultrastar series. Unfortunately, private customers will not be able to install one of these 3.5-inch storage monsters in their home computers in the foreseeable future. At the moment these HDDs are only available for companies. For tech enthusiasts, however, this technique is worth keeping an eye on.
An HDD consists of a number of components, the two most important of which are the magnetic disks and the read / write head. The magnetic disks contain the data, the head reads and writes them. Hard drives store data using a binary configuration. The write head moves across the rotating disks and uses magnetism to write data in a pattern of zeros and ones.
The EAMR hard drives from Western Digital (WD) from the Gold series offer double-digit terabyte capacities and are very expensive for HDDs.
© Western Digital
A hard drive is therefore often compared to a record player: the record contains the tones and the needle moves over a certain point to call them up. However, the data on a hard drive is so small that the head cannot be manually moved to a specific location. The computer does that. In contrast to LPs, the head not only reads the data, but also writes them.
The problem is that writes on traditional drives are unfortunately not as precise. This means that the bits cannot be packed as closely together. EAMR aims to solve this problem by making it possible to write bits much closer together on a disk. To do this, the WD drives apply power to the main pole of the write head during operation. This creates an additional magnetic field that contributes to a more consistent write signal. In this way, data can be written to the drive more precisely and at the same time packed in a higher density on the surface. This is why EAMR is such an advancement for hard disk drives: more precise writes mean more data can be written to the disks, which increases their areal density.
With hard disks, the magnetic disks and the read / write head are among the core components. The goal: to get as much data as possible on one disk.
However, EAMR is just one of several features that work together to increase the storage capacity of a hard drive. Another big step forward with the new WD Gold drives is the “Triple-State Actuator” (TSA). This mechanical solution positions the head even more precisely over the magnetic disks. Here, too, more precise writing processes help to increase storage capacity.
While high capacity hard drives are a tempting prospect for personal PCs, they are difficult to deploy right now, largely because of their cost. However, this could change in a few years. Helium-filled drives were initially only intended for companies, but were sold to private customers about three years later. Today, this technology is found in drives with a capacity of 12 TB or more.
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