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1. Mechanical hard disk drive (HDD)

The internal structure of a traditional mechanical hard drive

A mechanical hard disk drive (HDD) is also a common hard drive that we often refer to. Currently, most computers still use mechanical hard drives. The structure of mechanical hard drives is quite complex, they mainly consist of: disks, magnetic heads, disk shafts and control motors, head controllers, data converters, interfaces, caches, etc. d. of course circuit board and aluminum case. All platters in a mechanical hard disk are mounted on a rotating shaft, and each platter is parallel to each other. There is a magnetic head on storage surface of each platter, and distance between magnetic head and platter is less than a hair's length, diameter is still small, all magnetic heads are connected to magnetic controller heads, and magnetic head controller is responsible for movement of each magnetic head.

Second hybrid hard drive (SSHD)

Hybrid hard disk circuit board structure

As name suggests, a hybrid hard drive is a combination of a mechanical hard drive and a solid state drive. The main disk case is same as mechanical hard disk, but PCB has added an SSD module and flash memory particles. Hybrid hard drives use small capacity flash memory particles to store frequently accessed files, and capacity is typically between 8GB and 16GB. The disk is most important storage medium, while flash memory only serves as a buffer, storing most frequently used files in flash memory to reduce search time and increase efficiency. Currently, there are not many manufacturers producing hybrid hard drives, most representative of which are Seagate and Toshiba.

3. Solid State Drive (SSD)

SSD Internal Structure

Solid State Drives (SSDs), referred to as SSDs, are hard disk drives made from arrays of solid state electronic memory chips for solid state drives, and consist of a control unit and a storage unit (FLASH chip, DRAM). chip). The specifications and definitions of interfaces, functions and usage methods of solid state hard drives are exactly same as those of ordinary hard drives, and shape and size of products are also fully consistent with ordinary hard drives. It is widely used in military, vehicle, industrial control, video surveillance, network monitoring, network terminals, electric power, medicine, aviation, navigation equipment and other fields. In past two years, solid state drives have become increasingly popular. In fact, SSDs appeared relatively early, but due to technical and cost constraints, only in recent years have SSDs gradually entered mainstream consumer market. The structure of an SSD is much simpler than that of a mechanical hard disk. All important components of an SSD, including flash memory particles, main control chips, and cache memory, are integrated on a single circuit board.

After understanding basic structure of mechanical hard drive, SSD and SSHD hybrid hard drive, let's take a look at advantages and disadvantages of these three.

For and against

1. Mechanical hard drive

Advantages: large capacity, low price, long service life

Disadvantages. Compared to SSDs, mechanical hard drives consume more power, and among three types of hard drives, mechanical hard drives have slowest read speeds. Moreover, due to peculiarities of its own structure, it is highly vulnerable. When current hard disk is working, distance between magnetic head and magnetic disk is less than 0.01 micron. It can be assumed that when magnetic disk rotates at high speed, there will inevitably be real close contact between magnetic disk and magnetic disk. magnetic head after shaking hard disk, resulting in damage to disk platters. Therefore, do not shake hard disk strongly while hard disk is running.

Second hybrid hard drive

Benefits. A hybrid hard drive combines advantages of a mechanical hard drive and a solid state hard drive, and its performance is also in between. The price is also reasonable: currently, a 1TB hybrid hard drive costs about 600 yuan.

Disadvantages. A hybrid hard disk that combines advantages of both also inherits disadvantages of both, such as poor shock resistance, a severely limited number of erasures and writes caused by a single flash particle, etc. Fortunately, this flash driveThe memory only records frequently accessed files and only backup, not entire file storage in flash memory.

Third, SSD

Benefits: Read and write speeds are fastest of three. And because structure of a solid state hard disk is much simpler than that of a mechanical hard disk, it is simply a highly integrated board, so it has a very good shock resistance. Solid state drives consume less power than traditional hard drives. Since there is no mechanical motor and no fan, operating noise is 0 decibels. Lighter in weight compared to conventional 1.8-inch hard drives, weighing only 20-30 grams.

Disadvantages: small capacity, high cost, short service life. There are many SSDs on market today, but prices for SSDs of same capacity are quite different.