computer hard disk

The computer hard disk is a very important storage device in the computer, which is responsible for storing information such as the operating system, applications, files and data. Over time, the appearance and basic composition of computer hard drives have also evolved and improved. This article will from the appearance, basic composition, working principle, classification, maintenance and maintenance of many aspects, the characteristics and functions of computer hard disk in detail.

I. Introduction

A computer hard disk is a mechanical storage device used to store data and programs in a computer. With the continuous development of technology, the capacity and speed of computer hard drives are also increasing. At present, there are mainly two types of mechanical hard disk and solid state hard disk on the market, in which the mechanical hard disk uses a rotating disk and read and write magnetic head for data storage, while the solid state hard disk uses flash memory particles and controllers for data storage.

Second, the appearance of the computer hard disk

Computer hard drives are usually rectangular and about the size of the palm of your hand. The main interface types are SATA, SAS, USB, etc., of which SATA interface is the most widely used interface type at present. In addition, the external structure of the computer hard disk also includes the power interface, data interface, fixing screws and other parts.

Three, the basic composition of computer hard disk

1. Hard disk disk

Hard disk platters are the core components of a computer's hard disk and are used to store data. Platters are usually made of aluminum alloy and coated with a magnetic material. The disk rotates at a high speed, and the read and write head flies on the surface of the disk, and the data is read and written by changing the magnetic state of the surface of the disk.

2. Read and write heads

A read/write head is a part of a computer's hard disk used to read and write data. The magnetic head is usually made of ferrite material and has extremely high sensitivity and precision. The magnetic head realizes the reading and writing of the magnetic state on the disk through the principle of electromagnetic induction. When working, the magnetic head needs to be suspended at a certain distance from the surface of the disk to ensure the normal read and write operation.

3. Motor and controller

Computer hard drives also contain components such as motors and controllers. The motor is used to drive the rotation of the platter, usually a brushless DC motor. The controller is responsible for controlling the movement of the read and write magnetic head and data transmission and other operations, which are usually implemented by special chips. In addition, the controller also has error detection and repair functions to ensure data integrity and reliability.

Four, the working principle of computer hard disk

1. Read and write principles of computer hard disk

The read and write operation of the computer hard disk is realized by flying the read and write head on the surface of the disk. When the data needs to be read, the read and write head will find the corresponding data area on the surface of the disc, and then convert the magnetic state of the surface of the disc into an electrical signal through the principle of electromagnetic induction, and then transmit to the computer after amplification and processing. When data needs to be written, the read and write magnetic head will find the corresponding data area on the disk surface, and then achieve the data writing by changing the magnetic state of the disk surface.

2. Workflow of computer hard disk

The work flow of computer hard disk mainly includes the following steps: First, the computer issues read and write instructions to the controller; Then, the controller controls the motor to drive the disk rotation, and moves the read and write head to the corresponding data area; Next, the read and write head reads and writes data; Finally, the data after reading and writing is transmitted to the computer through the controller. In the whole process, the controller plays a core role, which not only controls the precise movement of the read and write head, but also handles tasks such as data transmission and error detection.

Five, the classification of computer hard disk

1. The difference between mechanical hard disk and solid state hard disk

Mechanical hard drives and solid state drives are the two main types of computer hard drives on the market today. Mechanical hard drives use rotating platters and read/write heads for data storage, while solid state drives use flash memory grains and controllers for data storage. Compared to mechanical hard drives, solid state drives have higher speed and stability, but they are also more expensive. In addition, the capacity of SSDS is usually smaller than that of mechanical hard drives.

2. Computer hard drives of different sizes and capacities

Computer hard drives come in a variety of sizes and capacities. Specifications mainly include interface type, disk number, cache size and other parameters; The capacity mainly includes different specifications such as TB level and GB level. Different specifications and capacities of computer hard disks are suitable for different application scenarios and requirements. For example, high-capacity mechanical hard drives are suitable for storing large amounts of data and files, while high-speed solid-state drives are suitable for programs and application scenarios that need to get up and running quickly.

3. Common computer hard disk models and sizes

(1) 2.5-inch hard disk: 2.5-inch hard disk is the standard size of notebook hard disk, small size, easy to carry. Its capacity is usually between 160GB and 2TB, and the speed is generally 5400rpm or 7200rpm. In addition, 2.5-inch hard drives are available in thinner models, such as 7mm and 9.5mm thicknesses, for different types of laptops.
(2) 3.5-inch hard disk: 3.5-inch hard disk is the standard size of desktop hard disk, the volume is larger, the capacity is usually between 500GB and 20TB. Its speed is generally 7200rpm or 5900rpm, and there are higher speed models up to 10,000 RPM or 15,000 RPM. The 3.5-inch hard disks also have different types of interfaces, such as SATA and SAS, which are suitable for different application scenarios and requirements.
(3) The M.2 hard disk refers to the solid-state hard disk with the M.2 interface, which has a smaller appearance size, faster read and write speed, and the price is similar to the SATA interface solid state disk. In addition to being a system disk, the M.2 hard drive can also be used as a mobile solid state drive. Some M.2 SSDS on the market using large brands of original particles have stable and reliable performance, such as the Inderm P3 series, with sequential write and sequential read speeds of up to 3000MB/s and 3500MB/s, respectively, basically reaching the upper limit of PCIe 3.0. There are three types of M.2 hard drives: SATA, AHCI, and NVMe, of which NVMe drives are the fastest.