On the mobile solid state disk: in addition to speed up, what problems have been solved

Xiaobian’s first contact with mobile hard disk was probably in 2008, which was a popular era of DIY hardware. For me, the mobile hard disk was already a perfect storage carrier. At the same price, the capacity of the mobile hard disk was larger than that of the U disk, and it also had certain portability. It also solved the problem that I used to reload the system and back up the data. It’s not too much to say that it’s a necessity in my life.

In the twinkling of an eye, in 2021, the mobile hard disk has also developed from mechanical to solid-state. As we all know, the speed of SSD is faster than that of mechanical HDD, but is the only way to improve the speed of mobile SSD compared with that of mechanical HDD? Let’s talk about one or two things here today.

Mobile mechanical hard disk: cheap big bowl, but many problems

At that time, the brand mobile mechanical hard disk didn’t have all kinds of advanced technologies. To put it bluntly, it was a 2.5-inch mechanical hard disk in a box, so many people chose the more affordable mod mobile hard disk at that time. At that time, such things solved many problems of data storage and transmission.

They are indeed affordable. In the era of low portability requirements at that time, they can meet the needs of many people, but the price is that if you accidentally drop them, your data may have to be recovered by a maintenance organization for hundreds of yuan. Even the brand of mobile mechanical hard disk, internal added a certain anti-seismic function, the fall protection ability is also very limited.

However, mobile mechanical hard disk will still have a good market in 2021 due to its unmatched capacity and cost performance. It only costs more than 300 yuan to get 1TB capacity, good portability, acceptable large file transfer speed and long-term optimized seismic capacity.

Cheap big bowl, enough to summarize the advantages of mobile mechanical hard disk, but in the file size with geometric speed expansion, as well as a variety of lightweight devices appear today, mobile mechanical hard disk transmission speed is slow, the problem of large size should also be to many people, mobile solid-state hard disk should also be born.

Mobile SSD: everything is good except expensive. It’s really fragrant

Solid state drive (SSD) is called a portable hard disk (SSD).

From the structural analysis, SSD as the carrier of mobile hard disk is more suitable than mechanical hard disk: no active components, lightweight, anti-seismic, but also provides the ability of high-speed data transmission, which can be said to make up for the short board of mechanical hard disk. Under the same volume, SSD can achieve a much larger capacity density than mechanical hard disk. For example, the enterprise product of Pico has 16TB capacity in the 2.5-inch, 7mm thick specification.

At present, devices are equipped with usb3.2gen2 interface, or even higher specifications. The speed of mechanical hard disk can only reach about 150MB / s, which makes the status of high-speed interface awkward. PSSD supporting SATA or nvme protocol can give full play to the performance of this kind of interface.

Some people may ask that some USB flash drives can read and write 300MB / S +. They are also in the category of PSSD, but they are smaller in size.

Then there is the seismic capability. One of the advantages of SSD compared with mechanical hard disk is that it has no active components. What are the disadvantages of moving elements? One is the heating caused by the friction of the components (such as the central bearing of the disk, the high-speed swing of the magnetic head, etc.), and the other is the complicated mechanical structure. The distance between the magnetic head and the disk is only 0.1-0.2 microns (or less). If there is a slight vibration, the magnetic head may scratch the disk and cause permanent damage. Even if some hard disks have technical blessing, they can take back the head to avoid damage when it vibrates, but it still depends on the face. Who knows whether the speed of the head taking back or the speed of the head scratching to the disk is fast at the moment of vibration.

SSD is soldered on a PCB board by the main controller and particles, as well as a bunch of electronic components. There are no active components, which greatly reduces the possibility of disk damage caused by physical impact. It can be said that even if you fall down dozens of times from the height of the figure, there will be bumps on the appearance, and there will be no problems in the use of SSD ontology in theory.

But it’s also a well-known reason. Because the cost of granular hard disk is here, SSD will be more expensive than mechanical hard disk.

Will all mobile hard disks become SSDs in the future?

It’s not impossible.

At present, the only problem that PSSD needs to solve is price. SSD particles have gone through the era of SLC, MLC and TLC, and now they have gone to QLC, and PLC particles will appear in the future. Theoretically, after TLC, the capacity cost of particles will be reduced, but the QLC particles currently on sale can not be recognized by people from the price alone, so whether the cost of particles can be reduced or not depends on the time to make a decision, and the cheaper solid particles may come out in a few years.

In terms of particle performance, the most “poor” QLC particles can also reach the read-write speed of ordinary mechanical hard disks, and the 4K speed is much more beautiful than the latter. Therefore, I don’t think it’s necessary to cut QLC particles across the board. After all, the only reason why it’s not popular is its price.

Moreover, most of the PSSD on sale now use TLC particles, combined with each unique algorithm optimization, the performance and life is not a problem at all. And don’t worry too much about performance.

While PSSD is going to replace the mobile mechanical hard disk, some people may ask: solid state hard disk is not suitable for cold storage, and mechanical hard disk is suitable for long-term storage. How can it be replaced?

Here is a little popular science: the data in the particle is stored by electrical signal, and the disk is stored by magnetic signal. After a simple understanding, we can know that in the case of cold storage, the retention time of electrical signal storage is certainly not as long as magnetic signal. According to JEDEC standard, data can be stored for 52 weeks at 30 ° C, almost a year, and up to 105 weeks at 25 ° C. But the disk can be simply preserved for decades, and the data is intact.

But you should understand that this is a mobile disk. The frequency of power on is much higher than that of the storage disk under your bed. It’s enough for a SSD to have no power for one year. If there is a need for long-term cold storage, it will be over with mechanical hard disk.

PSSD solves the problems of portability, shock resistance and speed. Although the price of PSSD is on the high side in mobile storage, there are plenty of discounts during the promotion period. If the price can be lowered in the future, it is a perfect mobile storage device.

Author: Anonymous



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