Hard disks, the heart of the information age, have evolved from horizontal to vertical recording to increase storage density. This technology arranges magnetic particles vertically to store more data, and experts from a variety of fields are working together to improve its performance.
Hard disks in the information age
The 21st century is known as the Information Age. The biggest challenge for scientists in the information age is to create more efficient storage devices. Computers store information just like humans. Humans don’t store information in their mouths, but in their brains, which are located in their heads. Just like humans store information in their brains, computers don’t store information anywhere.
How hard disks are built and how they work
If you look at the exterior of a hard disk, you’ll see nothing but a protective casing. However, when you look inside, you can see the complex design of a hard disk. The most important parts of a hard disk are the media (the spinning disks), the motor (which spins the media), and the head (the long, chopstick-like part).
The media is the information storage device, and it is the device that creates a magnetic field to perform the recording process of writing information and the playback process of reading the written information as needed. The magnetic recording process involves sprinkling very fine permanent magnets (particles) onto the disk and then moving an electromagnet close to it to change the polarity of the magnets, thus changing the polarity of the permanent magnets attached to the disk in the desired direction. How much information can be stored on a hard disk depends on the capacity of the media. The higher the density (number of particles) of the media, the greater the capacity.
The role of heads and how they record data
The head is the most important part of a hard disk, as it is responsible for storing and recording information as it moves over the media. The movement of the hard disk over the media can be compared to the movement of a crane. The head of a hard disk is an electromagnet, a temporary magnet. If you wrap a wire around a nail and connect a battery to the wire, the nail turns into a simple electromagnet. The head also has wires, and those wires are called coils. When current flows through that coil, it becomes an electromagnet, just like the nail. Writing and reading data to and from a hard disk is like Morse code. Morse code is a signaling system that uses “short” (0) and “long” (1) to send and receive signals to and from the other party. Similarly, hard disks use the polarity (N, S) of magnets to read and write data. The magnetic material applied to the surface of the media displays information as 0 in one direction and 1 in the other, depending on the electromagnet poles.
For example, suppose you want to store the information “Korea” on your computer. The computer analyzes the writing of “Korea” and converts it into a number of 0s and 1s that the computer can understand. If we replace “Korea” with 0 and 1, the result is “01101011 01101111 01110010 01100101 01100001”. To write this data, the head passes over the media, reversing the direction of the current flow as shown in the code above. When reading data from the media, it does the opposite: instead of passing current through it, the electromagnet passes over the media and determines whether the electromagnet is (+) or (-) based on the poles of the magnetic material, causing an induced current. This is how we read the data recorded on the media. To put it in a simpler way, the head is like a blind person reading a Braille book. The head moves over the media to read the information.
Horizontal vs. vertical recording
The traditional method of data recording is horizontal recording. In horizontal recording, the magnetic particles are placed parallel to the media. In this method, the head creates a horizontal magnetic field. However, as customers and industries have demanded higher hard capacities, new methods have been developed, one of which is vertical recording. The history of vertical recording, like that of horizontal recording, began decades ago. Many attempts have been made to develop vertical recording, and finally the industry has been able to successfully introduce high-density vertical recording. The development of high-density systems requires optimization of the head and media and requires the efforts of many scientists and engineers. Unlike horizontal recording, the magnets are positioned vertically on the media. If you compare horizontal and vertical recording, you can easily see the increased density of the magnets. In order to position the magnets in this way, the head’s storage method has to change, so it now records information vertically instead of horizontally.
The role and evolution of motors
Motors play many roles in hard disks, but the most important one is to spin the media quickly. Today’s hard disk motors on the market have a speed of 5400 RPM. In layman’s terms, this means that the motor spins the media 5400 times a minute. The faster the motor spins, the faster the stored information can be read. However, increasing the speed of the motor has the disadvantage of increasing the power consumption. Another disadvantage is the high production price.
The future and challenges of hard disk technology
In order to develop new hard disks, which are the storage devices of computers, specialists from different fields, such as electrical engineering, mechanical engineering, materials engineering, chemical engineering, and others, have to work together. Hard disk experts liken hard disk technology to low-flying airplanes. The way the head moves on the disk is similar to how an airplane flies at high speeds while maintaining a low height. It takes a lot of effort and money to develop such complex technology.
In recent years, the pressure to improve the performance of hard disks has increased, raising new technical challenges not only in storage capacity but also in data transfer speed, reliability, energy efficiency, and other areas. For example, high-speed interfaces such as NVMe are being introduced to increase the transfer speed of hard disks, and RAID technology is being widely utilized to increase reliability. While these technological innovations are overcoming the limitations of hard disks and opening up new possibilities, they also bring with them new challenges, such as higher prices and more complex system requirements.
Therefore, to succeed in this field in the future, it will be important to develop different and superior technologies to gain a competitive edge. Research is needed not only to improve existing technologies, but also to explore completely new approaches, which is how hard disk technology is expected to evolve. The challenges facing scientists and engineers are still great, but overcoming them will result in better storage devices that meet the demands of the information age.
