Computer

The evolution of HDDs that Seagate drives already have: TDMR

It is a question of the market. Information is increasingly “weighing” more, technology is moving towards higher resolutions, better audio, better video, all multichannel, servers and services provide increasingly better streams in terms of general quality … Dolby Atmos, HDR, 4K.

All this means that together with the greater dimensions of current games, greater fiber bandwidths and ultimately, a world where we want the best in our lives in terms of technology means that this data has to be stored in increasingly larger devices. number. This occupies a gigantic physical space with each passing year, it costs a lot to maintain 100,000 HDDs at optimal temperature and logically the energy consumption shoots up.

Only with 50% more capacity the resources consumed and the performance are greatly improved, not exponentially but in a higher percentage, so the hard disk industry is and will be under pressure until we have a device that equals or exceeds them .

TDMR, what is it exactly?

Two-dimensional Magnetic Recording or TDMR, which translated into our language means two-dimensional Magnetic Recording. The name is already quite specific in terms of what this technology achieves, but before getting into it, let’s take a bit of history, since it was Seagate that designed and opted for this technology back in 2013.

The curious thing about TDMR is that it is one of those developments that remain in the background, clouded or overshadowed by another technology that is slightly inferior, but that one wants to promote for marketing reasons despite the fact that the first is still used and is the basis of the second. and definitive.

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This way of increasing the capacity of hard drives came about when the PMR technology was coming to an end and after more than 6 years of development it was at the end of 2016 or the beginning of 2017 (it is not really clear when the first companies had samples of HDD) when TDMR made an appearance.

Why then is it not popular as such? You have to first understand how it works to understand what comes next. As we have anticipated, TDMR is a way of extending the life of granular “conventional” magnetic recording, or CGMR, in which PMR was embedded.

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At first, this new way of recording data was proposed to compete in high density, assuming a significant improvement, but it was not due to the technical problems that it caused and that could not be solved, and what TDMR achieves is to record the tracks on the HDD platters more narrowly.

What advantages are obtained?

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The theory said that with TDMR rates and densities above 15% would be achieved, but the reality is that they have remained at a more concise 10% according to Seagate itself. The problem is the so-called ITI or in other words, the magnetic interference that occurs between runway and runway. Reducing the space means that the writing head and the reading head have more trouble doing their writing and reading tasks in time and with precision, which means less performance and a higher failure rate.

To solve this, what was done is to include a series of heads to be able to read data from one or more tracks at the same time. The most obvious question is, what for? Well, because you can read the data from several inputs at the same time and determine which ones are correct, thereby improving the noise signal and using only a more powerful controller.

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The complexity of the HDD is increased, but the capacity is increased and more importantly, it is a previous step to adapt HAMR with greater ease since they are logically compatible with subtle but important changes.

In addition, by having multiple heads and after stabilizing and refining TDMR, what Seagate did was increase read and write rates at the cost of a controller with higher bandwidth capable of handling so much data.

Why hasn’t more TDMR been implemented?

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This is the funny thing about the technology itself, since it is not normally advertised under its name. Seagate called it TDMR but advertised it as PMR + and therefore it is difficult for us to find products that name it. In fact, sometimes PMR + is not even named, but simply PMR, which is about to say goodbye as the main focus to give life to HAMR on the desktop, because on the server it is a reality that in 2022 will be much more crowded.

When this happens, TDMR will definitely be forgotten by many, but others of us know that between PMR and HAMR there was a technology that laid the first and laid the foundations for the second with very high reliability and improved performance.

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