On the computer, the processed data is kept on RAM. However, the data on the RAM is stored in electrical environment. Therefore, they are volatile memories. The data on the RAM is erased when the computer is turned off or power is lost. There is a need for environments to allow data to be permanently stored so that users can access the data later. At this point, hardware such as floppy drive, hard disk, CD ROM, etc. is helpful. In such hardware, data is stored in different environments.
A hard disk is a memory unit that permanently stores data. Therefore, it is the most important hardware unit. The codes of the program to be executed are read from the hard disk and are stored on Ram memory. The codes are executed here and their tasks are executed. The data to be included is processed in the same way as Ram. Today, hard disk technologies are used externally and internally. Common hard drive manufacturers include Seagate (Maxtor (Quantum)), Hitachi (IBM), Toshiba, Wester Digital, Samsung.
There are 3 different types of hard disk.
1) HDD (Hard Disc Driver)
2) SSD (Solid State Driver)
3) HHD (Hybrid Hard Driver)
HDD (Hard Disc Driver)
They have the structure that holds the data on a magnetic disc that can be rotated about an axis. In addition to electronic and electrical components, there are mechanical components. When writing data on the disc, numbers are written with 1 and 0. One and the zeros are written on the disc in a magnetic sequence on the nested ring. A hard disk in its simplest form consists of the following parts. The physical dimensions of the hard disk can be 3.5-inch, 2.5-inch and 1.8-inch.
SSD (Solid State Drive)
HDD is a recording unit that begins to replace the disks. It is a data storage tool consisting of an electronic card with no disk, motor and reading head in its structure. Keeps data in SDRAM, DRAM or Flash memories. Because SSDs are not mechanical parts, the performance is better and the power requirement is lower.Data recovery capabilities are lower than HDD. They are quiet because they do not have mechanical structures. According to the test results, there is a performance surplus between 30-45% of HDDs. Despite the advantages, the demand cannot be achieved according to the hard drives.
HHD (HYBRID HARD DRIVER)
They are physically similar to hard drives. They have both disk and flash memory. Therefore, the SSD and HDD mix have a hybrid structure. They have a high size buffer with flash memory. This reduces the waiting times for disk access by using a faster flash structure than the mechanical system.