Tuesday, Aug 09, 2022, 18:41 Hardware

Researchers: HDDs Better For Environment Than SSDs

Both Apple and most other computer manufacturers have switched almost entirely from the previous industry standard (the hard drive) to solid state drives. For years now, all devices stemming from Cupertino have exclusively possessed SSDs as their method of data storage. Hard drives are no longer even a configurable option in the MacBook, Mac mini, and iMac. The once omnipresent magnetic data carriers are now only used for "data mining" or as back up media – such as in external drives, NAS boxes, servers, and research centers. Since purely electronic SSDs are significantly more energy efficient than their mechanical counterparts and thus require less energy during operation, one might appropriately (yet incorrectly) assume that they're also more friendly to the environment.

SSDs Have A "Dirty Secret"
Unfortunately, SSDs are not in fact more friendly for the environemnt – according to the claims of two scientists. Swamit Tannu from the University of Wisconsin-Madison and Prashant J. Nair from the University of British Columbia calculated the CO2 footprint of each method of data storage and published their results for the Hotcarbon 2022 workshop in a seven-page paper under the title "The Dirty Secret of SSDs: Embodied Carbon" ( PDF file). One flash-memory storage device with a capacity of one terabyte, used over five years, accounts for around 184 kgs of CO2 emissions. That's almost double the emission count of an equally large traditional hard drive – which amounts to slightly more than 99 kgs of CO2 emissions. The conclusion from Tannu and Nair: SSDs are much more damaging to the environment than HDDs.



Higher CO2 Emissions During SSD Production
The significant difference between CO2 emissions stems from the difference of emissions during production – and not the environmental operating cost after the fact. SSD production requires significantly more energy. This "CO2 chamber" accounts for more than 80% of an SSD's emissions. The initial emission cost incurred during production doesn't even come close to being offset following five years of operation after production – according to the researchers' calculations. An increase in in efficiency via reduction of structure width or the associated increase in transistors doesn't provide any significan temission relief. This accounts for the increase in energy requirement during the production of flash-memory chips.

Researchers: Flash-Memory Needs To Be Used For Longer
Tannu and Nair see only one way out of the current situation. In order to make SSDs more environemntally friendly than hard drives, we need to use or recycle current SSDs considerably longer. One possibility, according to the researchers, would be converting the currently common Multi-Level-Cells (MLC) into Single-Level-Cell-SSDs (SLC) after the end of their lifecycle via firmware modification. Although this would drastically reduce their storage capacity, the flash-memory would be usable for several more users. However, this process has yet to be tested in reality.

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