The HDD have been with us since the beginning of time and as such, have evolved into a number of improvements that have affected two classic parameters: higher capacity and faster. At the same time, their safety has increased, but it so happens that their basic structure, their components, the vast majority remain the same as 50 years ago. Today we will fully get to know the main protagonists of such a long career.
We are not going to logically go into explaining what a hard drive is, since it is part of popular culture and everyone at some point has seen or held one of them. The main thing about this is that we must know that your architecture has undergone little change as such and that this has made your industry suffer a lot against SSDs. Therefore, perhaps this industry should have put more meat on the grill and opted for new designs or concepts, since as we are going to see next, the parts of an HDD remain essentially the same as 5 decades ago.
In any case, these hard drives are called mechanical because they literally have mechanical parts that move inside them, so let’s see what they are and what each one of them is for so that we can better understand how a hard drive works inside. .
Parts of an HDD: small improvements that have made a lot of difference
Since 1956 the biggest change that hard drives have undergone at a functional level is the reduction of their form factor to 3.5 inches and 2.5 inches , as well as the connection interface to adapt to new speeds and times.
The reality is that they are still behind in performance than expected, since they have not managed to collapse even SATA 3 and the benefits are only focused on greater capacity as the main priority, being the secondary performance.
Security has remained for most of these years as the basic pillar of the industry and in recent years it has undergone a fairly important upgrade, especially influenced by SSDs and their failure rate and useful life.
For this reason and due to the growing investment of companies, the concept of HDD and its parts continues to be practically traced year after year, where the improvements are few, but they make a difference.
Dishes
The plates are a series of discs with a thickness not exceeding 0.5 mm and are responsible for storing the information through magnetic tracks. They obtain a central hole that varies in its diameter and where the motor that makes them rotate is located.
They are rigid, are stacked on top of each other, separated with true precision so that they do not touch at any time and are currently the biggest headache for the industry, since to increase capacity requires very sophisticated techniques and materials that allow a less grain, in order to record smaller tracks in the same dimensions.
All are composed of a very thin magnetic layer that helps the polarization of the tracks and until a few years ago they were made of different types of glass or ceramic.
Axis
The axis has a vital part of importance in an HDD, since in it the dishes are fixed as we have commented above. This axis fixes them in such a way that it does not allow even the slightest horizontal sliding of any of them, where it also has to be so well calibrated and with such precision, that in the cases of the HDD of greater capacity it must allow to rotate the same constant speed at a large number of them without any rotational loss.
As it is the wear part with the highest bill in the life of the HDD, manufacturers dedicate the best materials and bearings to it, since in the most extreme cases they have to rotate at 15,000 RPM per minute.
Such is the reliability given to it, that normally other parts fail before the motor or shaft.
Actuator and arm
They are in charge of positioning and writing on the plates. It could be said that today they are practically one, since the new mechanisms integrate fewer and fewer pieces to end with inertia and thus be more precise.
The actuator is a motor whose sole function is to control the movement of the arms. The higher the number of these, the better and more precise the actuator has to be, since the weight and inertia of such fast movements have a direct impact on the performance and reliability of the HDD.
The arms, on the other hand, are in charge of writing on the plates. For each plate there is an arm and this in its final part has what is known as a “slider”, which is the specific part that “floats” on the plate and is in charge of writing and reading on the disk.
To give us an idea of what this technology means in terms of precision, the glider floats at a distance of 40 atoms at a speed of 15,000 RPM. Putting a simile, it is as if an airplane turned at a speed of Mach 800 less than one centimeter from the ground
