external ssd HDD HardDrive Development MARM HARM

external ssd HDD HardDrive Development MARM HARM


m2SSD OEMexternal ssd In the past two days, we have seen reports that microwave-assisted hard disk technology is matureexternal ssd+ 8618750919058, then the storage density will be significantly improved.” Just over the weekendexternal ssd+8618750919058, briefly writing down the development of storage products.

divided into several parts in chronological order:

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two HDD mechanical hard disks (LMR/PMR horizontal/PMR vertical magnetic recording, SMR, HAMR/MAMR laser/microwave auxiliary magnetic recording).

three SDDs

four MRAM magnetic ram


Tape was the oldest data storage product. The principle is that the plastic tape is coated with magnetic powder, and the audio current generates electromagnetic fields with different directions and strengths through the electromagnet, and the magnetic powder records this information, which is the process of saving data. Its large size and slow speed were later replaced by CDs and HDDs, but they did not withdraw from the historical stage. Because its data can be stored for decades, it is still used in data storage companies.

-2 HDD

are very common storage products in our current lives, such as 2.5inch for notebooks/portable hard disks and 3.5inch for desktops.

its principle is similar to that of tape, mainly divided into magnetic mullets and heads. The magnetic mulle is used to store data, and the magnetic head is used to read and write data. The current magnetic mullet is disc-shaped, the hard magnetic material is sputtered on the glass or Al2O3 substrate, and the magnetic material in each area range can be used as a separate magnet, presenting N or S pole, representing 0 or 1. The head runs around on the magnetic muzzle to read or write signals (flipping the N or S poles).

the development trend/direction of HDD should be mainly in terms of storage density. Originally (not included in the volume of the earliest IBM refrigerators) the magnet recorded on the magnetic mullet 0 or 1 was within the surface. This is the LPR horizontal magnetic record.

two main aspects of the increase in magnetic storage density: one is the magnetic mule, and the other is the head. The breakthrough was based on the lab discovery of the GMR macromagnetic magnetoresistive effect around 1989. The advantages of this structure are its small size and high magnetic field sensitivity. Around 2000, IBM commercialized it on the disk head of the hard disk, which significantly improved the storage density of the hard disk.

when you are a master’s student, the teacher predicts that GMR may win during class. Sure enough, the 2007 Nobel Prize in Physics gave German and French scientists who discovered GMR at the same time in 1989 for their contributions to spintronics.

the volume of each individual magnet in the magnet can be reduced due to the application of the GMR high sensitivity head. Since then, PMR vertical magnetic recording has developed rapidly. Storage density has gone up another level.

the father of Japan’s vertical magnetic recording, gave a lecture at Landa when PMR was first introduced. Japanese manga describes how students carried a lot of books in their school bags when they went to school, but due to the birth of PMR, the storage density has increased significantly, and one book can be satisfied.

from PMR to today, there is no revolutionary technological breakthrough in hard disk drive products on the market. But optimizations continue all the time.

such as SMR tile-stacked magnetic recording. The tiles that used to be laid flat are now stacked on top of each other, partially intersecting. Then more tiles can be placed on the same area, and the storage density will be increased. SMR should have been proposed by Seagate at the earliest.

such as reducing the distance between the head and the magnetic mute, because the magnetic field strength and distance are inversely proportional. The closer the distance, the more sensitive it is. At present, the distance between the head and the magnetic mule has reached an astonishing number of nm. At this altitude, there are great challenges for the control of the flight of the magnetic head and the flatness of the surface of the magnetic mullet!

such as the increase in signal-to-noise ratio. Just to mention, the direction in which the head applies current changes when it writes the signal (0 or 1). This rise and fall time is already in the order of ps, which should be much faster than the time of the MOS tube in the circuit.

such as helium-sealed hard disks, which reduce power consumption due to the helium-gas environment.

to this day, PMR technology coupled with the continuous optimization of other technologies, the highest storage density on the market is 12-14Tb 3.5inch hard disk. Of course, there are many sets of magnetic mullets and heads in the hard disk.

(picture from the network, intrusion and deletion)

the next product with revolutionary technological breakthrough is HAMR/MAMR laser/microwave assisted magnetic recording technology, in fact, these two types of technologies have been studied at the time of master’s degree. It can be seen that there is a lot of road to go from the laboratory to the final product.

in principle, in simple terms, to increase storage density. If the head is reduced, then a magnetic field cannot be generated large enough to flip the magnetic field (write 0 or 1), so what? At present, two reliable solutions are to reduce the stability of the 0 or 1 region to be written on the magnetic pad. First, with laser heating, the magnetic material becomes unstable at high temperatures, and the relatively small magnetic field can be flipped (to achieve the purpose of writing signals). The second is to add microwaves, such as applying a microwave that is close to the essential frequency of the magnetic mute, then the magnet of ROI will become unstable, and the relatively small magnetic field can be flipped (to achieve the purpose of writing the signal).

HAMR product was first proposed by Seagate, which should be a demo sample two days before the 2012 German Physics Conference, but so far, the official product has not been listed. It can be seen that the technical difficulties are in it.

interject, the reliable lifespan of HDDs is about five years. If your hard drive has been in use for more than five years, it’s best to replace it with a new one, although it can still work. Hard drives have a price, data is priceless.

three SDD SSDs

this piece has not actually participated, not much to know. In recent years< span style=”color: rgb(0, 220, 220);” > SSD has developed rapidly, especially its breakthrough from 2D to 3D, before the information storage medium is 2D, after the elevator, the bungalow becomes a building. With the development of 64-layer and 96-layer NAND, the storage density has increased rapidly. Each storage unit is also in the range of tens of nm * tens of nm, which is larger than HDD.

why can’t HDD do 3D? Because the surface of a magnetic mullet corresponds to a magnetic head, the magnetic field passes through from top to bottom. If it is made into 3D, then the upper and lower layers of magnetic media will be affected by the magnetic field.

SSD is not unlimited, and each recording unit will affect each other while increasing in density.


actually came into contact with related work when I was a master’s degree. In principle, there are three layers of storage medium, and there is an interaction between the first and third layers of magnetic material, and these two layers are in the same state and different states are marked as 0 or 1. The current of spin excitation changes the state of one of the layers to achieve the purpose of writing 0 or 1. Currently both IBM and Samsung have demo samples.

summed up in one sentence: Technology is constantly advancing, and human beings have been pushing the limits. m2SSD OEMexternal ssd