What is SMR technology and how does it help hard disk manufacturers

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The lack of options of the manufacturers of hard disks before the increasing demand of the world of the data centers had its truce at the beginning of the year 2013, when a quite revolutionary technology caused that some and others continued of the hand. Almost providentially and after years of R&D, SMR technology came to mark the ground for SSDs and their capacity increase, but what is SMR really and how did it boost the desktop and server sector?

In any case, the objective of any manufacturer of hard drives is based on three factors: greater capacity, greater speed and greater security. To these could be added a room that is not always linked to them or at least not to all of them, as is a lower production cost.
SMR: the technology that achieved an increase in the density of the area

SMR technology was not the only one that manufacturers implemented at the time to achieve greater overall capacity in their HDDs, therefore, usually when talking about SMR we usually talk about PMR at the same time, since they are contemporary.

In any case, SMR is the acronym for Shingled Magnetic Recording and is a technology that has allowed to increase the amount of information bits that can be recorded in a specific area of a magnetic hard disk. Obviously, the more bits of information can be stored in a sector, the greater the capacity of the HDD.

SMR is almost an extension of PMR, since they don't understand each other without the other. PMR achieved something very important: reduce the physical limit of the HDD head when writing or reading. This managed to write more bits in the same space, which was a relief for the hard disk sector, but it was not enough.

SMR technology goes one step further and achieved something so far not conceived: allow a magnetic track to overlap a part of the previously written one in order to increase the density of the area. What is achieved is that it is possible that the reading head can obtain the written data of the uncovered part of the magnetic tracks.
Less space used for writing equals higher final density

To understand the revolutionary of this technique, it must be taken into account that in an HDD without it, the magnetic tracks are superimposed in parallel to each other and perpendicularly (only with perpendicular recording), that is, next to each other .

On the other hand, with SMR the tracks can be overlapped on top of each other because the reading head only requires a narrower area than the magnetic track that is written. This only works when the data to be written is new and not edited or overwritten.