What is a hard drive and how does it work?
On a daily basis, we constantly use different hard drives to carry out our computer work, but have you ever wondered how the information on the hard drive is stored? does the drive save? In simpler language, how is information written to the hard drive and read again at a later stage?
Typically, in a $500 laptop, 256GB of SSD storage space is considered, and all the different data can be stored on This model has a hard drive. However, in this article, we want to talk about how your data is stored on the hard drive. In short, it can be said that the hard drive installed on your system uses magnets to store information. When we compare this with CD, this approach can be more efficient. In fact, if we wanted to continue burning our large data on CDs, over time, we would face a large number of CDs, which would be difficult to maintain, and buying good quality CDs would seem expensive.
Buying memory SSD from SafirSoftHow does a hard drive work?
To fully understand a hard drive, you need to get to know this part physically. In general, inside a hard drive there are disk parts and above these parts, there is a space of a few millimeters. These discs are also called platters. These plates are polished to a very smooth, mirror-like surface and can hold a large amount of information.
Next up, we have the arm. This component reads and writes information on the disk. This arm constantly moves from the central part to the edge of the disk and reads or writes information through the very small heads it has. On average, the arm in home drives can oscillate approximately 50 times per second. This number can increase to thousands in many high specification machines as well as devices used for complex calculations.
For better understanding, for hard drives running at 5400 RPM, the arm moves 62 miles per hour. Also, the arm is only 10 nm away from the plate and the arm has to read or write information on the plate in this very small distance. hard drives use the concept of magnetism to perform this process. To better understand how a hard drive works, we need to review some basic concepts together. Let's talk about the concepts through which the hard drive stores information.
In very simple terms, hard drives use ferromagnetism to store all your files in a few seconds, but maybe this question is in the right now. What is ferromagnetism?
Probably you have already come across this experiment through the lessons of experimental sciences, where several pieces of paper are placed next to a magnet so that eventually the papers become magnetic. This is the behavior of certain metals that acquire magnetic properties when placed near a magnet. These materials are called ferromagnets. This change in the characteristics of the mentioned irons is used to store information on the hard drive. Similar to a mirror beneath a surface, the plate is made up of billions of tiny grains. These grains have intrinsic properties similar to those pieces of paper in high school experiments and can store magnetic information in the presence of a magnetic field. To store information, these grains can have two different states, and these states are known as magnetic moments.
Furthermore, unlike pieces of paper, the size of the grains is very small, and a square inch of plate can Store hundreds of gigabytes of data. Therefore, an electromagnet with a very small head is used to write information on these small grains. In the following, we will discuss how information is written on these grains using an electromagnet.
How to write information on a hard drive
Suppose your computer wants a file. save on your hard drive. This information is actually a number of zeros and ones that change the direction of the flow in the writing head. Due to the change in the current state, the polarity of the electromagnet induces a different magnetic field in the plate below it. It is these differences in the magnetic fields on the plate that create different magnetic moments in the grains.
So, if your system decides to store information 1, the grain in question must have a different magnetic moment compared to the information. have 0 These differences in the magnetic properties of the grains to the hard drive power allows to store information.
Understanding the different methods of storing information on a plate
By making the grains smaller, new challenges and problems appear. For example, small grains can lose magnetic information more easily due to environmental factors. Therefore, the meaningful moments must be arranged in a different arrangement to solve this problem.
The following are some different methods for storing information on the plates:
Longitudinal magnetic recording
As the name suggests, longitudinal magnetic recording (LMR) stores information longitudinally. This method means that the magnetic dipoles have the same arrangement as the head of the arm during the movement for writing. Although the LMR method works well, the size of the dipoles on the hard drive using LMR technology takes up a lot of space. For this reason, a density of 100 gigabytes per square inch is achieved by LMR.
Vertical Magnetic Recording
Vertical Magnetic Recording (PMR) is also known as conventional magnetic recording. , offers more storage than the LMR method. The reason for this increase is the difference in the arrangement of magnetic dipoles. Information in LMR method is stored longitudinally, but in PMR technology, dipoles are arranged vertically. Therefore, the bipolars on a PMR drive are perpendicular to the movement of the arm head during writing. This change in ordering increases the density of information. Likewise, each dipole takes up less space compared to the dipoles used in LMR technology. For this reason, in the PMR method, a density of 300 to 400 gigabytes per square inch can be placed.
Column Magnetic Recording
As mentioned earlier, information is stored on tiny grains inside the hard drive. These data storage seeds are placed in a circular circuit on the hard drive. In fact, these are the circuits and paths that the arm moves on to write and store information. Although these paths are placed close to each other in PMR and LMR technologies, these paths do not overlap. If an overlap occurs, problems can occur while reading the data. In overlay magnetic recording (SMR), tracks are overlapped to increase the amount of data that can be stored on a single drive. Due to the overlapping of paths, SMR technology increases the storage density by up to 25%.
Heat-assisted magnetic recording
However, the change from LMR to PMR technology results in a significant increase in the amount of information stored. It can be stored on a hard drive, this technology is still not enough for mega companies like Google, Facebook, Microsoft and Amazon that have at least 1200 petabytes of data. Therefore, to increase the data density on the hard drive, a method called heat-assisted magnetic recording (HAMR) has been invented. This technology actually heats the plate using lasers so that the seeds can be placed close to each other so that the information they store is not lost due to environmental factors. Because of this advancement, hard drives that use HAMR technology can store more than 2 TB of data per square inch.
In addition to the arrangement and order of the bipolars, how your hard drive is partitioned It will also affect the performance.
Reading information from the hard drive
Now that we understand how information is written on hard drives, in the next step we will discuss how the hard drive can Read the written information.
As can be seen in the image below, the hard drive consists of a set of tracks. As we have mentioned, these are the ones that store the information. When you save a file on the computer, the arm's write head will write part of the way, and the hard drive will remember the location of the file.
When you open the file, the CPU asks the hard drive to do the same. The hard drive puts the arm in the same direction as the information was previously written in that section.
It is in this section that the read head of the hard drive should show its performance. Just like the hard drive's write head, there is a very large electromagnet (GMR) for the read head. However, unlike a write head that induces a magnetic field, the GMR head detects changes in the magnetic fields on the platter. Because of these features in the head Reading, this head can read information from the plate. These are the processes of reading and writing information that cause a certain noise to be heard from the hard drive. Of course, it goes without saying that the noise of the hard drive is at the level of normal low-frequency noise. If the intensity of the noise is higher than usual, it is possible that the hard drive is facing problems in reading data.
SSD or HDD; Which hard drive is better to buy?
Solid state hard drives or SSD are technologically more modern than HDD. SSDs provide the user with faster read and write speeds, and this is definitely in the user's favor to provide better facilities and comfort by spending more money. However, you can save some money by purchasing an SSD with a smaller storage capacity. It takes up space on the hard drive, so the best decision is to buy a mechanical hard drive so that you can have more data at a lower cost. However, you should take care and take necessary measures for SSD and HDD so that the hard drive remains healthy for a long time.
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