Internal 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.

The computer hard disk is the main storage device of the computer. Hard Disk (Hong Kong and Taiwan called hard disk, English name: Hard Disk Drive, short for HDD full name Winchester hard disk) consists of one or more aluminum or glass disks. The discs are covered with a ferromagnetic material.
The vast majority of hard drives are fixed drives, permanently sealed and secured in the hard drive. Early hard disk storage media were replaceable, but today's typical hard disk is a fixed storage medium, sealed inside the hard disk (except for a filter hole to balance air pressure). With the development, removable hard disk also appeared, and more and more popular, more and more types. Most of the hard disks installed on microcomputers are called "winchester hard disks", or simply "warm disks", because they use Winchester technology.

An HDD is a mechanical storage device consisting of a disk, a magnetic head, and a motor. It has the characteristics of large storage capacity, low price and high durability, and is suitable for personal computers, servers, multimedia storage and data backup scenarios. Compared with SSDS, HDDS have the advantage of being cheap and widely applicable, but they are slower to read and write and less earthquake-resistant.
HDD is called hard disk drive, the internal disk, magnetic head, motor and other components, by rotating the disk and moving the magnetic head to read and write data. This article describes the working principle, features, and application scenarios of HDD.
First, the working principle of HDD

An HDD is a mechanical storage device that consists of a disk, a magnetic head, a motor, and other components. The disk, the most critical component of an HDD, is a metal disk coated with a layer of magnetic material.

The magnetic head is a device used to read and write data, which is located on the surface of the disk and can be moved to different tracks to read and write data. A motor is a device used to drive disk rotation, which can make the disk spin at high speed. HDDS work by spinning disks and moving magnetic heads to read and write data.

A primary computer storage medium consisting of one or more aluminum or glass discs. The discs are covered with a ferromagnetic material. The vast majority of hard drives are fixed drives, permanently sealed and secured in the hard drive. Removable hard drives are becoming more and more popular, and there are more and more types.

A hard disk drive (HDD) is a device in a personal computer that controls the hard disk's addressing and access to data. Through the hard drive, the computer can store data. Although hard drive and hard disk are two concepts, because the two are usually packaged together, either hard disk or hard drive usually refers to the device formed by combining the two.

A mechanical hard disk mainly consists of a magnetic head and a disk. The magnetic head is a key part of the mechanical hard disk to read and write data. When a mechanical hard disk is working, the head writes track data or reads existing data while the disk is spinning.

Early desktop computer hard disk use IDE interface, IDE interface hard disk is cheap, but the cost performance is low; Most personal computers use SATA interfaces or SCSI interfaces. The advantage of a SCSI interface hard disk is that up to seven different devices can be attached to the same controller panel. Since the hard drive spins at a constant high speed of 3000-15,000 revolutions per minute, it takes only a short time to read data from the hard drive.

If the SSD is powered off, the current may disturb the main control, which causes the main control to break down. Therefore, users who use solid state drives, please do not arbitrarily power off. Although SSDS are in principle several orders of magnitude less likely to break than mechanical hard drives, they still cannot withstand human failure.

Second, the characteristics of HDD

1, large storage capacity: storage capacity can reach several TB or even tens of TB, to meet the needs of large-capacity data storage.

2, read and write speed is slow: because HDD is a mechanical storage device, read and write speed is slow, such as reading data, need to wait for the head to move to the correct track.

3, the price is cheap: compared with SSD and other solid state drives, the price of HDD is cheaper.

4, high durability: HDD is a mechanical storage device, relatively durable.

5, wide range of application: HDD is suitable for a variety of computers and servers, can meet the needs of different application scenarios.
3. Application scenarios of HDD

HDD is applicable to a variety of computers and servers and can meet the requirements of different application scenarios, including the following:

1, personal computers: HDD is suitable for personal computers, can be used to store operating systems, applications, documents and other data.

2, server: HDD is suitable for servers, used to store a large amount of data, such as website data, database data, etc.

3, multimedia storage: HDD is suitable for multimedia storage, can store music, video, photos and other multimedia data.

4, data backup: HDD is suitable for data backup, can be used to back up important data, protect data security.
Fourth, HDD and SSD comparison

Solid State Drive (SSD) is a type of solid state drive (SSD), which has higher read/write speed and stronger shock resistance than HDD. Power consumption is low, but SSDS are relatively expensive.
V. Summary

The features of HDD include large storage capacity, slow read and write speed, low price, high durability, and wide application range. HDD is applicable to a variety of computers and servers and can meet the requirements of different application scenarios.

Compared with SSDS, the advantages of HDD include cheap price and wide application range, and the disadvantages include slow read and write speed and poor shock resistance.

Introduction to Portable Hard Disk alias name is Portable ssd

Portable hard disk is a kind of portable storage device, which uses the hard disk as the storage medium, so that computers can easily exchange large-capacity data. The device is designed to emphasize portability, making it ideal for situations where you need to carry large amounts of data around with you. There are two main types of mobile hard drives: mobile solid state drives (SSDS) and mobile mechanical hard drives (HDDS). Mechanical hard drives are generally more cost-effective and relatively inexpensive, while solid state drives offer faster transfer speeds and are suitable for users who need to transfer data quickly, especially when working away from home.

The components of a mobile solid-state drive usually include a main controller, a memory unit, and a bridge chip. The housing is generally made of metal, which not only helps to dissipate heat, but also provides protection against pressure and shock. When the hard drive is connected to a computer or phone, an indicator will light up, indicating that the hard drive is working. In terms of interface, the common USB 2.0/3.0 type, and more high-end products may be equipped with USB 3.2Gen 2x2 interface, which means that the portable hard disk transmission speed of this interface can reach 2000MB/s, which means that several GB of video files can be transferred in a few seconds.

Product characteristics

Large capacity

Portable Hard Disk can provide a considerable storage capacity, is a more cost-effective mobile storage products. Portable hard disk can provide users with large storage capacity and good portability at an acceptable price range. At present, the mobile hard drives on the market can provide 320GB, 500GB, 600G, 640GB, 900GB, 1000GB(1TB), 1.5TB, 2TB, 2.5TB, 3TB, 3.5TB, 4TB and other capacities, up to 12TB capacity, to a certain extent to meet the needs of users. With the development of technology, the capacity of Portable Hard Disk will be larger and larger, and the volume will be smaller and smaller.

Small size

Most of the Portable Hard Disks use USB and IEEE1394 interfaces, which can provide higher data transmission speed. However, the data transmission speed of the Portable Hard Disk is limited to a certain extent by the interface speed, especially in the USB1.1 interface specification products, when transferring a large amount of data, it will test the patience of the user. USB2.0 and IEEE1394 interfaces are much better.

High speed

Most of the Portable Hard Disks use USB, IEEE1394, eSATA interfaces, which can provide a high data transmission rate. However, the data transmission rate of the Portable Hard Disk is limited by the interface speed to a certain extent, especially on the products of the USBl.1 interface specification, which will test the patience of the user when transferring large data. The USB2.0, IEEE1394, eSATA interfaces are much better. USB2.0 interface transmission rate is 60MB/s, IEEE 1394 interface transmission rate is 50 ~ 100MB/s, and eSATA, when exchanging data with the host, read a gigabyte order of large files in a few minutes, especially suitable for video and audio data storage and exchange.

Easy to use

Now the PC is basically equipped with USB function, the motherboard can usually provide 2~8 USB ports, some displays will also provide USB adapters, USB interface has become a necessary interface in personal computers. USB devices can be used in most versions of WINDOWS operating systems without the need to install drivers, with a true "plug and play" feature, flexible and easy to use.

Safe and reliable

Data security has always been the most concerned issue of mobile storage users, and it is also an important standard for people to measure the performance of such products. Portable Hard Disk has won the favor of many users with the advantages of high speed, large capacity, lightweight and convenient, and the greater advantage is the security and reliability of its stored data. This kind of hard disk is similar to the structure of the laptop hard disk and uses silicon disk. This is a more durable platter material than aluminum and magnetic, and has greater storage capacity and better reliability, improving data integrity. The use of silicon as a material disk drive, featuring a smoother disk surface, effectively reduces the number of irregular disks that may affect the reliability and integrity of the data, and the higher disk hardness makes the USB hard disk have high reliability.

Matters needing attention

The use of Portable Hard Disk should pay attention to the following problems:
1, do not use for a long time. Use a Portable Hard Disk with general materials, it is best not to plug in the computer for long-term work, Portable Hard Disk is used for temporary exchange or storage of data, not a local hard disk. Compared with the internal hard disk will work in a harsh environment at all times, the working time should be shortened as much as possible.
2. Do not defragment the disk. Do not defragment the removable hard disk, otherwise it will easily damage the hard disk. If you really need to organize, the method can be used to copy the data in the entire partition, and then copy back.
3, do not mix the power supply line. Do not mix the power cables. Because the power cables of the Portable Hard Disk box are dedicated, the voltage of the power cable interface may be different. If you insert them improperly, the box will be burned, and the hard disk will be burned.
4. Don't beat. Don't beat, take lightly; Pay attention to the temperature, do not overheat; Dry and waterproof, pull back first.
5, do not implement hot swap in the transmission process to prevent electromagnetic, dust, water and other external interference.

dimension

At present, mobile hard drives can be divided into three types by size: 3.5-inch desktop hard drives; 2.5-inch laptop hard drive; 1.8-inch micro hard disk. Among them, the 3.5-inch desktop hard disk has the advantages of fast speed and large capacity, but it is large, heavy and inconvenient to carry, and because the hard disk is designed for the desktop, the shockproof performance is poor, but there are still certain advantages in terms of price and capacity. 2.5-inch notebook hard disk is specially designed for the notebook, the size and weight are smaller. There is also a special design in shock resistance, good shock resistance, the most used in the current Portable Hard Disk. 1.8 inch micro hard disk, also designed for notebooks, good seismic performance, and size, weight is also the smallest of the three, but its price is higher, the capacity is smaller, more difficult to popularize, more suitable for special needs users.

capacity

Capacity is the storage space of the mobile hard drive. In 2006, the mainstream hard drive capacity was increased from 160GB to larger capacity. At present, the 250G and 320G products are quite cost-effective. The world's largest single disk capacity reached 750G, 320G product market has been quite mature, the price is also very reasonable. And 400G or above products are still a high-priced series, ordinary users rarely consider. Although 160G and 250G are the mainstream capacity, but limited to cost and actual use needs, for general office and home applications, the choice of 80G or even lower 40G has been fully able to meet the needs.

port

The interface type refers to the type of interface used by the Portable Hard Disk to connect to the computer system, rather than the interface type of its internal hard disk. Because the Portable Hard Disk can be connected to the system through the interface, the interface determines the performance and data transmission speed of the connection with the system. At present, the common data interfaces of mobile hard drives are USB and IEEE1394. USB is the mainstream interface of Portable Hard Disk at present, and it is also the interface of almost all computers, with the advantages of hot swappable, unified standards, and multiple external devices. There are two USB standards: USB1.1 and USB2.0. The USB2.0 transfer speed is up to 480Mbps, which is 40 times that of the USB1.1 interface. USB2.0 requires motherboard support and can be backward compatible. The same brand USB2.0 Portable Hard Disk box is 30 to 50 yuan more expensive than the USB1.1, but because of the huge difference in speed, USB2.0 has become the mainstream of the market.