What is HDD?

hdd refers to a mechanical hard drive, which is mainly composed of platters, magnetic heads, platter shafts, control motors, head controllers and other mechanical devices. Mechanical hard drives are located in dust-free factories throughout the production process. Any tiny particle of dust falling on the disk surface will have a devastating blow to the entire disk when it is working at thousands of revolutions per minute.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

hdd's full name is "Hard Disk Drive", which means "mechanical hard disk" in Chinese. The reason why it is called a mechanical hard drive is because it is completely made of mechanical structure inside.

Mechanical hard disk is a traditional ordinary hard disk, which is mainly composed of: platter, magnetic head, platter shaft and control motor, magnetic head controller, data converter, interface, cache and other parts.

The magnetic head can move along the radius of the disk. Coupled with the high-speed rotation of the disk of several thousand revolutions per minute, the magnetic head can be positioned at a designated position on the disk. Data read and write operations. Information is written to the disk through a magnetic head that is very close to the magnetic surface, and the electromagnetic current changes the polarity and is written to the disk. The information can be read in the opposite way. As a precision device, dust is the enemy of the hard disk, so the air entering the hard disk must be filtered.

Principle:

All the platters in a mechanical hard drive are mounted on a rotating shaft, and each platter is parallel to each other. There is a magnetic head on the storage surface. The distance between the magnetic head and the disk is only 0.1μm~0.5μm, and the higher level has reached 0.005μm~0.01μm. All the magnetic heads are connected to a magnetic head controller, which is controlled by the magnetic head controller. Responsible for the movement of each magnetic head. The reading and writing speed of a mechanical hard disk depends on the speed of the motor, because the motor needs to be relied on to drive the disk to rotate at high speed so that the magnetic head can find the designated position for reading and writing.

Note:

The mechanical hard drive is located in a dust-free factory during the entire production process. Any tiny particle of dust falling on the disk will undergo thousands of revolutions per minute. In this state, it will have a devastating blow to the entire disk. Common mechanical hard drives have 5400 rpm and 7200 rpm, so friends, please do not dismantle the mechanical hard drive by yourself.

Explanation: Comparison of the advantages and disadvantages of mechanical hard drives and solid-state drives

Hard drives are divided into mechanical hard drives (HDD) and solid-state drives (SSD). Let’s take a look at the differences between mechanical hard drives and solid-state drives. Comparison of the advantages and disadvantages of solid-state drives

1. Shock and drop resistance: Mechanical hard drives are all disk-type, and data is stored in disk sectors. The solid-state drive is made of flash memory particles (i.e., memory, MP3, U disk and other storage media), so there are no mechanical parts inside the SSD solid-state drive, so it will not be affected even when moving at high speed or even with flipping and tilting. to normal use, and can minimize the possibility of data loss in the event of collisions and shocks. Compared with mechanical hard drives, solid hard drives have an absolute advantage.

2. Data storage speed: The speed of mechanical hard disk is about 120MB/S, the speed of SATA protocol SSD is about 500MB/S, and the speed of NVMe protocol (PCIe 3.0×2) SSD is about 1800MB/S. S, the SSD speed of NVMe protocol (PCIe 3.0×4) is about 3500MB/S.

3. Power consumption: The power consumption of solid-state drives is also lower than that of mechanical hard drives.

4. Weight: Solid-state drives are lighter in weight, 20-30 grams lighter than conventional 1.8-inch hard drives.

5. Noise: The mechanical hard disk needs to rotate the disk at high speed when working. The high-speed rotation of the motor inevitably brings noise and heat. Since solid-state drives have no mechanical parts or flash memory chips, they have the characteristics of low heat generation and fast heat dissipation. They also have no mechanical motors and fans, and the noise level is 0 decibels.

6. Maintenance and optimization methods and performance: The structure of mechanical hard disk determines that there are not many ways to optimize it, while solid-state hard disk can be optimized in many more aspects.

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