What is a hard drive and why is it needed
Each computer has a hard drive or, as it is often called, a hard drive, which is the main place to store all the information used by the computer and its user. The installed operating system, all programs used by the user, and data are stored on the hard disk. The processor takes the information necessary for processing from the hard drive and then writes it back to the media. The amount of information that is stored on a hard disk depends on its size.
The very first models of hard drives allowed storing up to 10 mb of data on their disks, in those days it was a lot. Now modern media can store thousands and tens of thousands of megabytes. The amount of memory on modern models is calculated in gigabytes and terabytes. This makes it possible to store a huge amount of films, music, video clips, games and other data. A significant increase in the amount of memory on the HDD is associated with the progressive development of computer technology, as a result of which films, games and other data take up more and more free space.
Design Features of Winchesters
A modern hard drive consists of several metal disks, on which information is recorded. The discs are coated with iron oxide or other special composition that can store the effect of a magnetic field. The number of disks depends on the volume of the medium and usually ranges from 1 to 3. Metal disks are perfectly smooth, smooth and balanced, so they can rotate at high speed, according to the standard it can be 5400, 7200 or 10000 revolutions per minute.
Special heads with highest positioning accuracy move around the discs. Each disk has 2 magnetic heads. Reading data from the surface of the disks is carried out by installing special magnetoresistive heads, they work depending on how the magnetic field on the surface of the disk changes. Data is transmitted to the computer as a result of receiving an analog signal that goes into digital form.
On discs, information is located in tracks arranged in a circle. To work with data on media, magnetic heads move along tracks. The movement of the heads is carried out through the use of a special solenoid drive. Such heads can be accessed anywhere on the disc due to the high rotation speed. The heads are located on both sides of the disks, so each of them carries out work on one side and is fully responsible for it.
The sector on the hard drive allows you to store 512 bytes of information, and each track of the hard drive consists of many sectors. The maximum amount of information contained on the hard drive depends on the number of sectors, heads and cylinders. In terms of the number of HDDs, the HDDs may be the same, but their memory sizes will be completely different. This is due to the fact that to increase the volume it is more convenient to increase the density of sectors on each of the disks than to increase their number, which will lead to a significant increase in the size of the medium. The development of computer technology leads to the fact that each PC component becomes smaller in external dimensions, and opportunities, on the contrary, increase.
There are concepts like physical disk allocation and logical. The physical is how the storage medium is arranged inside, and the logical is how the computer sees it. In reality, the physical and the logical are completely different. If, for example, 3 disks can be physically installed inside the hard drive, then logically there can be any number and any volume, one logical disk can have the size of two or more physical disks and vice versa.
In the production of hard drives, it is almost impossible to avoid damage to sectors or tracks, but they are not used and are not taken into account by the media due to the marks.
Hard drives are intended for use in home PCs, and are for use in servers. The latter are subject to much greater requirements, because they work with a significant load and should provide high performance and speed.
In order to choose the right hard drive for certain purposes, you need to understand a large number of characteristics. The first thing you should pay attention to is the form factor. On stationary PCs, 3.5-inch hard drives are installed, and on laptops 2.5. There are also other less common form factors. The second important parameter is the interface through which the device connects to the computer. The PC uses various variations of the SATA interface.
One of the important parameters is the capacity, which determines the amount of data stored on the device. The speed of rotation of the shaft on which the disks are located affects the speed of work with information.