What are solid state drives and mechanical hard drives

Solid state drive (SSD) is a hard drive made of solid-state electronic storage chip array, consisting of a control unit and a storage unit (FLASH chip, DRAM chip). Mechanical hard disk is a traditional ordinary hard disk, which mainly consists of platters, magnetic heads, platter shafts and control motors, head controllers, data converters, interfaces, caches and other parts.

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

What is a solid state drive?

Solid State Drive (Solid State Disk or Solid State Drive, referred to as SSD), commonly known as solid state drive.

Solid state drive is a hard drive made from an array of solid-state electronic memory chips.

It got its name because solid capacitors are called Solid in Taiwanese English. SSD consists of a control unit and a storage unit (FLASH chip, DRAM chip).

Solid-state drives are exactly the same as ordinary hard drives in terms of interface specifications and definitions, functions and usage methods, and their product appearance and size are basically the same as ordinary hard drives (emerging U.2, M.2 and other forms The size and shape of solid-state drives are completely different from SATA mechanical hard drives).

It is widely used in military, vehicle, industrial control, video surveillance, network monitoring, network terminals, electric power, medical, aviation, navigation equipment and many other fields.

The chip has a wide operating temperature range, commercial products (0~70℃) and industrial products (-40~85℃). Although the cost is higher, it is becoming popular in the DIY market.

Because the technology of solid-state drives is different from that of traditional hard drives, many emerging memory manufacturers have emerged. Manufacturers only need to purchase NAND particles, match them with appropriate control chips, and write the main controller code to create a solid-state drive.

The new generation of solid-state drives generally adopt SATA-2 interface, SATA-3 interface, SAS interface, MSATA interface, PCI-E interface, M.2 interface, CFast interface, SFF-8639 interface and NVME/AHCI protocol.

What is a mechanical hard drive?

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 to read and write data. 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.

All the platters in a mechanical hard disk are mounted on a rotating shaft. Each platter is parallel to each other. There is a magnetic head on the storage surface of each platter. Between the magnetic head and the platter The distance 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, and the magnetic head controller is responsible for the movement of each magnetic head.

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

1. Shockproof 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: Since Solid Hardware has no mechanical parts and flash memory chips, it has the characteristics of low heat generation and fast heat dissipation, and there are no mechanical motors and fans.

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