For SSDs, I believe that my classmates are already very familiar with it. Talking about the advantages of SSDs is also very simple, with the word 'fast'! If someone asks you what is M.2, what is NVMe? I believe you may not be able to answer Come up, so today we will give you a slogan about the terminology of SSD, let everyone enter into the DIY God.
About the product interface: SATA/M.2/PCIe
Currently, most of the consumer-grade SSDs on the market are SATA or M.2 (including PCIe). First of all, the SATA interface is essentially the legacy of the traditional mechanical hard disk era. The most popular hard disk interface Form. As a result of being born out of traditional mechanical disks, the SATA interface is highly compatible. Almost all types of motherboards are perfectly supported. It is also the most widely available hard disk interface on the market.
In the era of SSDs, SATA interfaces have always maintained the highest shipments and market share, and are also the preferred solid-state types for general friends and friends. Unlike the traditional mechanical disk era, SATA interfaces that mount solid-state drives are in terms of performance standards. With the highest level of SATA III, the theoretical maximum speed is 6Gbps.
According to the current actual application situation, minus the transmission loss, the final read performance of most SATA interface-based SSDs should be above 500 MB/s, in other words, under SATA III, the read speed of SSDs. Less than 500MB/s are garbage.
Recall that M.2 interface, the so-called M.2 interface is a new interface for solid-state hard disk came into being. According to the size of solid-state hard disk, M.2 interface card slot will have many sizes such as 2280/2256, the current mainstream M.2 interface The solid state size is almost 2280 size.
The essence of the M.2 interface is the PCIe slot. According to the transmission protocol implemented by the SSD, the transmission performance is also very different. It is the difference in the transmission protocol. The internal M.2 interface can be simply divided into Take the M.2 interface of the PCIe channel and the M.2 interface that does not take the PCIe channel.
In other words, in the world of M.2 interface, there are different interfaces depending on the transmission protocol. This requires our attention in particular. This is also where many unscrupulous merchants prefer to conduct word games to deceive consumers. Executing PCIe The M.2 interface of the channel is far superior to the ordinary M.2 interface in terms of performance and cost, but there is almost no difference in appearance between the two. When consumers purchase M.2 interface products, they must go through the data query and repeatedly Confirm whether the M.2 interface products with non-PCIe channels were purchased at high prices.
About the transmission protocol: AHCI/NVMe
As we mentioned above, according to the different transmission protocols, the performance and cost of M.2 interface products have huge differences. Actually, in the solid-state drive industry, the most mainstream transmission protocol has actually two types. One is The AHCI protocol, the other is the NVMe protocol.
The so-called AHCI, full name Serial ATA Advanced Host Interface/Advanced Host Controller Interface, is an interface standard jointly developed by several companies under the guidance of Intel, which allows storage drivers to enable advanced Serial ATA functionality. The meaning and function of the agreement, we as general consumers do not need to know in detail, the only thing to note is that when selecting and using SATA interface SSDs, be sure to turn on the AHCI mode in the motherboard settings.
This is because, when the AHCI mode is turned on, it can significantly reduce the number of useless seeks and shorten the data search time of the hard disk. This allows the disk under multi-tasking to exert its full performance and effect. According to related performance tests, after the AHCI mode is turned on, , About 30% increase in SSD read and write performance.
At present, the mainstream SATA interface products on the market all support only the AHCI mode. At the same time, some M.2 interface products also support AHCI. Another transmission protocol is the NVMe protocol that stands out for the future performance in recent years. The so-called NVMe protocol. The protocol is a non-volatile memory-based transmission specification. The NVMe specification is customized by a working group of more than 90 companies. Intel is the main leader. Team members include Micron, Dell, Samsung, Marvell, NetApp, EMC, IDT and other companies.
The purpose of this specification is to take full advantage of the low latency and parallelism of PCI-E channels, as well as the parallelism of contemporary processors, platforms and applications, to greatly improve the read/write performance of SSDs under controllable storage costs. Reducing the high latency caused by the AHCI interface completely liberates the extreme performance of SATA era SSDs.
In other words, the birth of the NVMe protocol is to proceed from the transmission protocol to further increase the actual read/write performance of the SSD and improve the product transmission efficiency. In general, NVMe-based SSDs far exceed the SATA interface in read/write performance. The limit of 6Gbps, close to 1000MB/S.
In addition, the SSDs that currently support the NVMe protocol are almost all M.2 interfaces on the interface type. They use the PCIe channel. That is, all SSDs based on the SATA interface cannot support the NVMe protocol. Enjoy the limit performance brought by the new agreement. At this point, we can determine whether the maximum reading speed of the product exceeds 600MB/S as a simple basis.
About the core components: Flash/master
Finally, let's talk about the core components of the SSD, the flash memory chip and the main control chip. Flash memory, also called flash memory, is a kind of non-volatile memory, which can still save the written data in case of power failure. Data, but in units of fixed blocks, not individual bytes.
According to different uses and specifications, there are many different variants of flash memory. Today we mainly discuss the most commonly used NAND flash memory chips used in storage devices such as solid state drives.
NAND flash memory particles, a member of the Flash family, were first developed and marketed by Hitachi in 1989. As NAND flash memory particles have many advantages such as lower power consumption, lower price, and better performance, they have become the largest in the storage industry. Important storage material.
According to the differences in density of electronic units in NAND flash memory, they can be further divided into SLC (Single Level Memory Cell), MLC (Double Layer Memory Cell), and TLC (Triple Layer Memory Cell). These three types of memory cells have significant differences in lifetime and cost. The difference.
SLC (Single-layer storage), single-layer electronic structure, when the data is written, the voltage change interval is small, the service life is long, the read/write frequency is more than 100,000 times, the cost is high, and it is mostly used in enterprise-level high-end products.
MLC (multi-layer memory), using double-layer electronic structure with different voltages and different voltages, has a long lifespan, acceptable cost, multi-use civilian high-end products, and the number of reading and writing is around 5000.
TLC (triple layer storage) is MLC flash memory extension, TLC achieves 3bit/cell. The highest storage density is 1.5 times that of MLC. The lowest cost cost, low mission life, read/write times of 1000~2000, is the current mainstream. Manufacturers preferred flash memory particles.
With the development of the times, the technology of NAND flash memory particles has advanced by leaps and bounds, and has gradually formed several large-scale professional flash memory particle manufacturers. These manufacturers can directly cut wafers and separate out NAND flash memory particles. They are generally called as original manufacturers of flash particles. .
They are Samsung, Toshiba, SanDisk, Intel, SK Hynix, and Micron, among six particle manufacturers. According to statistics, the flash memory capacity of the six companies accounts for almost 90% of the NAND flash memory market, and almost all of the The creation and upgrading are dominated by several original factories. When we select SSDs, we can start from the flash granules and try to select the SSDs produced by the above six major manufacturers. As for the main control chip, as its name implies, Like a CPU in a PC, it is equivalent to the brain of a solid-state drive, and it has the role of command, operation, and coordination.
Its specific role is as follows: Firstly, the load of data on each flash memory chip is reasonably allocated, all flash particles can work normally under certain load, coordination and maintenance of the cooperation of particles in different blocks, and the other is to bear the entire data. Transit, connecting the flash memory chip and the external SATA interface, three are responsible for completing the internal instructions of the SSD, such as trim, CG recovery, wear and balance.
In view of the fact that the differences in the absolute performance of current major control chip manufacturers are not obvious, the major leading chip manufacturers, Hui Rong, Qunlian, Marvell, and Samsung, and Toshiba’s own R&D are all relatively good choices. It is necessary to pay attention to the old and stable problems of the main control chip.
When we select the SSD master control, we can determine how many vendors use this master control scheme to query through the network. After all, as a highly monopolistic industry, there are also a few options for SSD manufacturers to choose from. The master plan that most manufacturers use is not the best solution, but it must be the most secure solution.
From the interface to the protocol, to the core control, I hope that the common sense of these SSD products can help people to a certain extent. When purchasing a solid-state drive, we can provide a reference to avoid being deceived because we don't know about it. After all, solid-state drive products are at the forefront. High, cheated or hurt.
