In recent years, SSD has grown rapidly, the entire industry has undergone a lot of changes, Hong Wang found that there are a lot of friends on the semiconductor solid-state hard drive is not very understanding, just know that the emergence of SSD is the innovation of the mechanical hard drive. Today, Wang wang for everyone semiconductor comprehensive knowledge about science and how it works SSDs.
Above all, from the structure of SSD is, SSD is divided into basic components: controller chips, flash memory chips, firmware algorithms , Below we elaborate duties and affect the performance of the work of the three.
Master
SSD controller is essentially a processor, mainly based on ARM architecture, which has a similar processor and the phone side, there are some SSD manufacturers to master the use of RISC architecture, it has the computing power of the CPU level, common master brand: Hui Wing, group together, Marvell, Samsung.
For now, the computing power of the SSD controller chips, the size of the core area (number of transistors), the number of cores, the frequency is determined by the manufacturing process. Its specific role in the performance of, first, a reasonable allocation of the data load on each flash memory chips, flash memory so that all particles are able to work under a certain load, coordination and maintenance of different blocks of particles of collaboration; two is to assume the entire data relay, connected external SATA interface and flash memory chip; command completion of the three is solid charge of the internal hard disk, such as a trim, CG recycling, wear leveling. It can be said, a master chip directly determines the practical experience and the life of the SSD.
SSD foundation: Flash particle
SSD storage is used, there is no flash particles, will not have a storage carrier. I.e. the Flash flash memory, a nonvolatile memory, i.e., you can still save the data that has been written in the case of power failure, and is fixed in units of blocks, rather than individual bytes. Today we focus on is for the solid-state hard drives and other storage devices, the most commonly used NAND flash memory particles, ICAMX NAND are to undergo a rigorous test of good die, based on its excellent Nand flash security of supply capacity, effectively guarantee the stability of the product the user data security. Guarantee optimal cost-effective in the current stock prices of the severe form of flash memory to provide adequate supply.
NAND flash memory particles, is a family of flash memory, first developed by Hitachi in 1989 and the market, due to the NAND flash memory particles with lower power consumption, lower prices and better performance and many other advantages, has become the storage industry's most important raw material storage. Flash SSD particles impact on the performance of about 60%, selection and application flash particles critical to the performance of the SSD, according to the difference electron density NAND flash memory cell, it can be divided into SLC, MLC and TLC, this three storage units there is a clear difference in the life expectancy and cost, they can follow in detail the difference between the semiconductor earlier article [Wang Wang difference between SLC and MLC flash and TLC particles of the three, which is good value for money? ].
Firmware algorithms
SSD firmware is to ensure that a very important part of SSD performance, mainly for the drive controller. There may be a friend in doubt, SSD drives have what it takes? This should be talking about the structure of the SSD, although the structure of SSD looks a lot simpler than HDD, but in fact the mechanism was complex than HDD. For example, the need for SSD FTL layer through direct dialogue and systems, flash memory must be able to re-write data and then completely erased, so SSD Trim need to re-flash the "clean." As another example, SSD requires a very well-balanced algorithm is written so that all particles are balanced is consumed, and will not cause a part of the particle write of their life, and of other particles unused.
Firmware algorithm is very large, error correction code (ECC), bad block management, garbage collection algorithms, etc., so difficult to write SSD firmware, can be seen.
SSD firmware is good or bad is especially important, both products of the same Master and the same particles, because of their different firmware, may lead to a completely different life, and read and write performance. I can responsibly tell you that if the impact of particles in a solid state disk performance is about 60%, then the impact of the firmware will account for more than 20%. The better the quality of the firmware, the entire SSD of the more outstanding quality.
SSD SATA interface and the interface M.2
After understanding the basic structure of the SSD, we will look at SSD interfaces, the current interface is divided into the mainstream SSD, SATA 3.0, M.2, PCI-E three kinds, U.2 and mSATA currently rare, but here introduce more.
M.2 or SATA and the main difference is that the PCI-E: the two different channels. Understanding will bring both channels into the same car, PCI-E channel is like two cars traveling at high speed, while SATA channels like cars driving on the rugged mountain road, you quickly say what speed?
Different interfaces SSDs speedometer
We can see from the figure above, the current maximum transmission speed of the mainstream SATA 3.0 channels of 6Gbps, the actual rate of up to 560MB / s, SATA channel has been unable to meet the growing solid-state hard drive read and write speed, the PCI-E Solid State Drive It came into being. Why is my SSD M.2 interface, but speed is not fast? M.2 originally called NGFF, full name is the Next Generation Form Factor. The interface is very special, supports SATA and PCI-E two channels, is misleading.
In fact, not all of M.2 SSDs read and write speeds are fast, if the channel is using SATA interfaces M.2 solid-state drive, read and write speeds will not exceed 550MB / s. Also note that some motherboard manufacturers M.2 interface to select the CPU native PCI-E channel, some extended out through the PCH South Bridge, which could have an impact on the speed of SSDs.
For chestnuts, let's look at two solid hard disk speed comparison, the left is SATA SSD right is PCI-E SSDs.
Both the AS SSD run sub-rate gap significantly, whether it is continuous read and write, or 4K test, PCI-E SSDs are far ahead of SATA SSDs, the composite score higher PCI-E Solid State Drive SATA SSDs more than three times. To help you understand, Wang Wang various semiconductor interface and speed comparison tabulated, so that you can glance.
Although the PCI-E SSDs have many advantages, but not everyone is suitable to buy, first, more expensive, and second PCI-E bus channel will occupy less CPU entry and midrange platforms, the number of channels, are not suitable Add PCI-E SSDs.
To sum up: Wang Wang semiconductor suggest that you buy SSD, or to look for the brand, whether in life or speed has irreplaceable advantages, ICAMX will also introduce market-oriented SSD, so stay tuned!