Shulou(Shulou.com)06/01 Report--

[preface]

Hello, everyone. Welcome to Xiaoyu's article. In the last issue, we briefly explained the simple differences, advantages and disadvantages of HDD (mechanical disk) and SSD (solid state disk), but this is only a small beginning, in the days to come. I will explain to you more knowledge and anecdotes related to solid state. In this issue, let's tell the story of the interface. Many people are going to ask, aren't there two kinds of interfaces? SATA and M.2 interface. In other words, it is true to say that, but if you are more specific, why are there these two interfaces? It is estimated that many people do not know that the interface also has a story.

[iterative update: the trend of interface miniaturization]

With the further development of computer miniaturization, the interface is constantly changing, and the common mobile phone interface has been unified from a variety of interfaces.

There used to be a box of such universal interfaces, which is something to look forward to. However, due to the inconvenience of leaving home and the non-standard manufacture of mobile phone chargers, the interface has gradually changed from fancy interface to Micro USB, and gradually replaced by Type-C.

The same is true for hard drives, with IDE, SATA, mSATA, ngff (that is, M.2), U.2 and other interfaces constantly updated with the development of computers. The interface that runs counter to miniaturization and convenience is naturally eliminated with the emergence of new technologies.

[start of start: IDE]

DIYer, who is a little old or has a lot of contact with things, may find an old hard drive somewhere in the home, yes. It is an old-fashioned broadband hard disk. In today's computer city, many older computer repairers are still calling SATA disks serial port disks (IDE disks are parallel port disks, as shown in the picture).

But the vitality of electronic products should be known, the rapid development of technology after more than a few years of use will be out of date, IDE is no exception, when the bandwidth speed of 133MB/s reaches the bottleneck. The new technology has also been applied-- SATA.

The version of PS:IDE is more complex, a total of 7 versions, here because of the long time and almost no actual effect, so I won't talk about it.

[SATA]

When the IDE interface is about to reach a bottleneck, SATA technology in 2001, like today's 5G technology, has been established.

Compared to IDE,SATA can be said to be more familiar than IDE, if you turn on the computer to watch this article, it is believed that 99% of people will use the hard drive of SATA interface in their computers. If you have used earlier products, you will find that there is a SATA2.0 on the motherboard parameters. Today, the speed of the SATA interface on the motherboard is 3.0 and 2.0, which can no longer reach our desire for speed.

As shown in the figure above, there are three versions of the SATA interface (here it refers to the 7-pin data + 15-pin power ordinary SATA interface), and this doubling of bandwidth also gives us a better experience. However, when the HDD mechanical disk is not restricted by the bandwidth, the sudden emergence of NAND flash memory chips is gradually used in the market. The emergence of high-speed SSD solid-state disk makes us find that the 6Gbps bandwidth of SATA3 has become a new bottleneck. The theoretical value of the bandwidth of the main control eight channels has basically exploded, while there are differences in the study of the new interface, while miniaturization can be said to be urgent in the notebook, because the notebook simply does not have so much space to accept the SATA high-capacity solid state, and now the SATA solid state is basically added by removing the drive bit and adding the tray.

[mSATA]

Is it very similar to the new interface M.2? Indeed, M.2 appeared in the first place to replace mSATA. Increase speed by taking up two channels (lane) through the pass-through CPU

[SATA Express]

Since we want to increase the bandwidth and consider compatibility with the old interface, this strange SATAe (xpress) interface appears, which is compatible with the SATA protocol while supporting the NVMe protocol. However, the problem arises, in the era of miniaturization, you come up with such a big thing, you can say goodbye to the notebook. And it doesn't have its own power supply, so it's embarrassing not to promote it.

[M.2]

If you ask to buy a solid state disk when the price is abundant, M.2 is the first choice. The solid state of the SATA protocol, on the way to send data to CPU, first passes through memory, and then to CPU. After a tour, the manufacturer focused on the mature PCI for a long time, extended in the PCI technology, and occupied several lane to achieve the condition of direct CPU. Let's not mention M.2 here, because M.2 will be specially built in the future. But M.2 is actually a special kind of SATAe.

Three different specifications of M.2

[U.2]

U.2 (SFF-8639), unlike M.2, this thing starts with 4 lane, and can make a larger capacity, of course, the price, hehe. However, what is even more unfriendly is that solid state is expensive, but the motherboard that supports it is more expensive. So the solution to the experience is to transfer the card.

[PCI-E]

Guess what this is? Graphics card? NO, this is solid. Large capacity to take the PCIe interface solid state, the price is also very touching.

[summary]

Someone asked me before, how long do you think my disk will last? I said, if you don't inherit it, you can use it for the next generation.

Again, the history of solid state is relatively short, compared with the history of mechanical decades, the history of solid state may only be less than 1/10 of mechanical history, but its speed of development can not be ignored. In American science fiction in the 1970s, they imagined that a hundred or several decades later, short interstellar travel would become commonplace, but the computer they used was still a CRT (commonly known as big-ass display) display, from which we can see that computer technology has gone beyond the imagination of science fiction writers. Therefore, the low cost and the improvement of the rate of quality products brought about by the maturity of new technology is the absolute truth of continuous development. Therefore, when something is so cheap that ordinary people can think about it, it is the real technological improvement.

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