these methods allow smaller regions
of a disk to be magnetized, resulting
in higher capacity. However, these approaches also boost costs, and result in
density scaling gains of only about 15%.
Researchers are now exploring
other technologies that could one day
replace disks, tapes, and flash memory—or at least supplement them for
specific uses. Underpinning this is the
fact that up to 90% of the data generated by computers and other digital
systems is never accessed again; it simply lies idle, consuming ever-growing
mountains of storage media or servers.
Likewise, there is the issue of hard
drive capacity. “The problem with today’s systems is that they deliver no
more than one terabyte per square
inch,” says Karthik V. Raman, a former
IBM research scientist who now leads
a research team at the Tata Institute of
Fundamental Research (TIFR) in India.
The net effect is that current storage technologies—particularly disk-based servers and systems—consume
massive amounts of physical space,
particularly when they involve large
numbers of devices and media, such
as tapes or disks. Yet, even tape produces enormous volume of physical
objects. It is estimated that humans
produce approximately 2. 5 quintillion bytes of data each day and, overall, nearly 3 zettabytes of data exist in
the digital world. All these bytes require increasingly large data centers
that consume massive amounts of energy, along with other resources.
However, Raman points out, “Cre-
ating new types of storage with greater
capacity doesn’t solve the problem by
itself. There’s a need to develop bet-
ter ways to direct and redirect data for
faster processing.” Heckel and Grass,
for instance, have focused on using
DNA as a data storage mechanism.
The idea, first presented by George
Church, a molecular biologist and
geneticist at Harvard Medical School,
involves writing data to DNA material,
which could conceivably store that
data for hundreds of thousands, or
even millions, of years. Church says
the purpose of DNA storage “isn’t to
reinvent the hard drive, it’s to intro-
duce a medium that is ideal for ar-
chiving and long-term storage.”
Others are taking a different tack
for keeping data intact for long pe-
riods of time. For example, Peter G.
Kazansky, a professor at the Uni-
versity of Southampton in the U.K.,
has developed a method that uses
an ultrafast short-pulse laser to etch
data into the bulk of silica material.
“A single disk using this technol-
ogy could store 360 terabytes of data,
compared to a Blu-ray disk that can
store about 45 gigabytes,” he says.
Moreover, the data would potentially
stay on the disk for approximately 14
billion years. The project has caught
the eye of Microsoft, which is work-
ing to produce a commercially viable
version of the technology within a de-
cade (and its Project Silica is focus-
ing on ways to use the technology in
the cloud).
Tape Prevails
Remarkably, all storage devices and
use cases eventually lead back to
tape—at least, for the foreseeable fu-
ture. While tape is not as flexible or
convenient as hard drives, SSDs, and
other media, it remains cost-effective
and highly reliable. What’s more, ad-
vancements in tape continue to out-
pace other storage technologies. In
2017, IBM and Sony announced a new
magnetic tape system capable of stor-
ing 201 gigabytes of data per square
inch in a single palm-sized cartridge.
The technology has a theoretical limit
of 330 terabytes per square inch. The
world’s largest hard drives, on the
other hand, require twice the physi-
cal space, but hold only 12 terabytes
per square inch. The most advanced
SSDs hold about 60 terabytes per
square inch.
Many experts say the practical and
cost advantages tape has over hard
drives and other storage technologies
will likely grow over the next several
years. Tape won’t ever threaten hard
drives and SSD for dominance, but it
will remain at the center of storage—
and provide a strong insurance policy
for the likes of Google. Mark Lantz,
manager of Advanced Tape Technologies at IBM Research Zurich, noted in
an August 2018 IEEE Spectrum article
that researchers continue to boost the
density and capacity of tape, and the
trend will continue for some time.
“Tape may be one of the last information technologies to follow a Moore’s
Law,” he wrote.
To be sure, tape remains viable and
valuable—and the situation is not likely to change anytime soon. Concludes
Grass, “Other emerging technologies
will eventually change the way data is
stored. But for archival data storage,
tape is the technology to beat.”
Further Reading
Blawat, M., Gaedke, K., Hütter, I., Chen, X.,
Turczyk, B., Inverso, S., Pruitt, B. W.,
and Church, G.M.
Forward Error Correction for DNA Data
Storage. Procedia Computer Science,
Volume 80, 2016, pp. 1011-1022.
https://www.sciencedirect.
com/science/article/pii/
S1877050916308742?via%3Dihub
Zhang, J., Čerkauskaitė, A., Drevinskas, R.,
Patel, A., Beresna, M., and Kazansky, P.G.
Current Trends in Multi-Dimensional
Optical Data Storage Technology, Asia
Communications and Photonics Conference
2016, Current Trends in Multi-Dimensional
Optical Data Storage Technology, Wuhan
China, November 2-5, 2016.
https://doi.org/10.1364/ACPC.2016.AF1J.4
Zhang, J., Čerkauskaitė, A., Drevinskas, R.,
Patel, A., Beresna, M., and Kazansky, P.G.
Eternal 5D Data Storage by Ultrafast
Laser Writing in Glass. Proc. SPIE
9736, Laser-based Micro- and
Nanoprocessing X, 97360U ( 4 March
2016); doi: 10.1117/12.2220600; https://doi.
org/10.1117/12.2220600
Heckel, R., Mikutis, G., and Grass, R.N.
A Characterization of the DNA Data Storage
Channel, eprint arXiv:1803.03322. March
2018. https://arxiv.org/abs/1803.03322v1
Samuel Greengard is an author and journalist based in
West Linn, OR, USA.
© 2019 ACM 0001-0782/19/4 $15.00
Researchers
are now exploring
other technologies
that could one
day replace disks,
tapes, and flash
memory—or at least
supplement them
for specific uses.