tag:theconversation.com,2011:/au/topics/hard-disk-drives-6845/articlesHard disk drives – The Conversation2023-10-02T19:11:50Ztag:theconversation.com,2011:article/2088592023-10-02T19:11:50Z2023-10-02T19:11:50ZWhat has the Nobel Prize in Physics ever done for me?<figure><img src="https://images.theconversation.com/files/551265/original/file-20230930-15-nkkytb.jpeg?ixlib=rb-1.1.0&rect=53%2C0%2C6000%2C3997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/luminous-white-led-bulb-on-wooden-2096282497">Shutterstock</a></span></figcaption></figure><p>Each October, physics is in the news with the awarding of the Nobel Prize. The work acknowledged through this most prestigious award often seems far removed from our everyday lives, with prizes given for things like “<a href="https://www.nobelprize.org/prizes/physics/1966/">optical methods for studying Hertzian resonances in atoms</a>” and “<a href="https://www.nobelprize.org/prizes/physics/1999/">elucidating the quantum structure of electroweak interactions</a>”.</p>
<p>However, these lauded advances in our basic understanding of the world often have very real, practical consequences for society.</p>
<p>To take just a few examples, Nobel-winning physics has given us portable computers, efficient LED lighting, climate modelling and radiation treatment of cancer. </p>
<h2>Thin magnets and portable computers</h2>
<p>In 2007, the physics Nobel was awarded jointly to Peter Grünberg and Albert Fert for the discovery of “<a href="https://www.nobelprize.org/prizes/physics/2007/press-release/">giant magnetoresistance</a>”. </p>
<p>In the late 1980s, Grünberg and Fert (and their research groups) were independently studying very thin layers of magnets. They both noticed that electricity flowed through the layers differently depending on the direction of the magnetic fields.</p>
<p>These teams were looking to understand fundamental properties of very thin magnets. However, their findings led to something we now take for granted: portable computers. </p>
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<img alt="A photo of an opened hard drive on a yellow background." src="https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551266/original/file-20230930-27-sxcuty.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The ‘giant magnetoresistance’ effect won its discoverers the 2007 Nobel Prize in Physics – and made portable hard drives possible.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hard-disk-drive-open-cover-computer-2115380288">Shutterstock</a></span>
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<p>At the time, most computers stored information on a hard disk drive made of a magnetic material. To read the information from the drive, a very small and very accurate magnetic field sensor is needed. </p>
<p>The discovery of giant magnetoresistance allowed for the development of far more sensitive sensors, which in turn made hard disk drives and computers smaller. (Today, magnetic hard disk drives are being overtaken by even smaller <a href="https://en.wikipedia.org/wiki/Solid-state_drive">solid state drives</a>.)</p>
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Read more:
<a href="https://theconversation.com/how-to-store-data-on-magnets-the-size-of-a-single-atom-82601">How to store data on magnets the size of a single atom</a>
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<p>In short, we would not have laptops without the discovery that won the 2007 Nobel Prize in Physics. </p>
<p>The effect of this research – like that of so much fundamental research – was completely unanticipated.</p>
<h2>A light bulb moment</h2>
<p>Sometimes, however, physics research does have a practical goal all along. One such example is the quest for energy-efficient lighting.</p>
<p>Old-fashioned incandescent light bulbs are highly inefficient. Because they work by heating a wire until it glows, they waste a lot of energy as heat. In fact, less than 10% of the energy they consume goes to producing light. </p>
<p>In the 1980s, scientists realised light emitting diodes, or LEDs – small electronic components that emit light of a specific colour – would make more efficient light sources. But there was a problem. Although red and green LEDs had been developed in the middle of the twentieth century, nobody knew how to make a blue LED.</p>
<p>LEDs are thin sandwiches of materials that respond to electricity in a very particular way. When an electron moves from one energy level to another inside the material, it emits light of a specific colour. </p>
<p>All three colours of light (red, green and blue) would be needed to produce the kind of white light people want in their homes and workplaces. </p>
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<img alt="A photo of a strip of blue LED lights against a dark background." src="https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551274/original/file-20231001-19-qlom3i.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The invention of blue LEDs made it possible to create white light far more efficiently than with incandescent bulbs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vertical-shot-blue-led-tape-glowing-2101501642">Shutterstock</a></span>
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<p>In the early 1990s, in the culmination of almost 30 years of work by many groups, the missing blue LEDs were found. In 2014, Isamu Akasaki, Hiroshi Amano and Shuji Nakamura <a href="https://www.nobelprize.org/prizes/physics/2014/press-release/">received the physics Nobel</a> for the discovery. </p>
<p>The layers of material chosen to make up the sandwich, plus the quality of each layer, had to be refined in order to make the first blue LED. Since the initial discovery, materials scientists have continued to improve the design and manufacture to make blue LEDs more efficient.</p>
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Read more:
<a href="https://theconversation.com/your-phone-screen-just-won-the-nobel-prize-in-physics-32456">Your phone screen just won the Nobel Prize in physics</a>
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<p>Lighting accounts for up to 20% of total electricity consumption. LEDs use roughly <a href="https://www.sustainability.vic.gov.au/energy-efficiency-and-reducing-emissions/save-energy-in-the-home/lighting/choose-the-right-led-lighting">one sixth as much energy</a> as incandescent light bulbs. They also last much longer, with a lifetime of around 25,000 hours. </p>
<h2>Climate models, radiation and beyond</h2>
<p>Environmental endeavours are probably not what springs to mind when you think of the Nobel Prize in Physics. Yet another example also comes to mind, the study of a chaotic and complex system with great importance to us all: Earth’s climate.</p>
<p>Half of the 2021 Nobel Prize in Physics was given to Syukuro Manabe and Klaus Hasselmann, scientists who developed <a href="https://www.nobelprize.org/prizes/physics/2021/summary/">early models for Earth’s weather and climate</a>. Their work also linked global warming to human activity.</p>
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<img alt="A black and white photograph portrait of a woman." src="https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=815&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=815&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=815&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1025&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1025&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551275/original/file-20231001-17-ef6emp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1025&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Marie Curie was awarded the Nobel Prize in Physics in 1903 for her work on radioactivity.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Marie_Curie#/media/File:Marie_Curie_c._1920s.jpg">Wikimedia</a></span>
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<p>Of the 222 people awarded the physics Nobel since 1901, <a href="https://theconversation.com/and-then-there-were-three-finally-another-woman-awarded-a-nobel-prize-in-physics-104323">only three have been women</a>. The most famous of those three is perhaps Marie Curie, who took home one quarter of the prize in 1903. </p>
<p>Curie’s work on understanding how atoms can decay into other kinds of atoms, producing nuclear radiation, profoundly changed life in the twentieth century.</p>
<p>The study of nuclear radiation led to the development of nuclear weapons, but also to radiation treatment for cancer. And further, it has led to carbon dating to determine the age of artefacts, allowing us to better understand <a href="https://www.ansto.gov.au/news/radiocarbon-dating-supports-aboriginal-occupation-of-south-australia-for-29000-years">ancient civilisations</a>. </p>
<p>So when we find out who is awarded the 2023 Nobel Prize in Physics, no matter what it’s for – and prospects include research on quantum computing, “slow light” and “self-assembling matter” – we can be sure of one thing. The awarded research will likely end up affecting our lives in extraordinary ways that may not at first be apparent.</p><img src="https://counter.theconversation.com/content/208859/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Livesey does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The science that wins the Nobel Prize in Physics each year can be hard to get your head around – but it often has real everyday implications.Karen Livesey, Senior Lecturer of Physics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/826012017-08-24T14:06:12Z2017-08-24T14:06:12ZHow to store data on magnets the size of a single atom<figure><img src="https://images.theconversation.com/files/183289/original/file-20170824-25612-fy7mwk.png?ixlib=rb-1.1.0&rect=24%2C247%2C1193%2C845&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Magnetism is useful in many ways, and the magnetic memory effect appears even at the atomic level.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:PSM_V83_D111_Force_flow_of_a_magnetized_steel_sphere.png">Popular Science Monthly</a></span></figcaption></figure><p>There is an adage that says that data will expand to fill all available capacity. Perhaps ten or 20 years ago, it was common to stockpile software programs, MP3 music, films and other files, which may have taken years to collect. In the days when hard disk drives offered a few tens of gigabytes of storage, running out of space was almost inevitable.</p>
<p>Now that we have fast broadband internet and think nothing of downloading a 4.7 gigabyte DVD, we can amass data even more quickly. Estimates of the total amount of data held worldwide are to rise from <a href="https://www.emc.com/leadership/digital-universe/2014iview/executive-summary.htm">4.4 trillion gigabytes in 2013 to 44 trillion gigabytes by 2020</a>. This means that we are generating an average of 15m gigabytes per day. Even though hard disk drives are now measured in thousands of gigabytes rather than tens, we still have a storage problem.</p>
<p>Research and development is focused on developing new means of data storage that are more dense and so can store greater amounts of data, and do so in a more energy efficient way. Sometimes this involves updating established techniques: recently IBM announced a <a href="https://www.theverge.com/2017/8/2/16074568/ibm-330-terabytes-record-uncompressed-data-cartridge-cartridge-tape">new magnetic tape technology</a> that can store 25 gigabytes per square inch, a new world record for the 60-year-old technology. While current magnetic or solid-state consumer hard drives are more dense at around <a href="http://www.computerworld.com/article/3030642/data-storage/flash-memorys-density-surpasses-hard-drives-for-first-time.html">200 gigabytes per square inch</a>, magnetic tapes are still frequently used for data back-up. </p>
<p>However, the cutting edge of data storage research is working at the level of individual atoms and molecules, representing the ultimate limit of technological miniaturisation. </p>
<h2>The quest for atomic magnets</h2>
<p>Current magnetic data storage technologies – those used in traditional hard disks with spinning platters, the standard until a few years ago and still common today – are built using “top-down” methods. This involves making thin layers from a large piece of ferromagnetic material, each containing the many <a href="https://www.nde-ed.org/EducationResources/HighSchool/Magnetism/magneticdomain.htm">magnetic domains</a> that are used to hold data. Each of these magnetic domains is made of a large collection of magnetised atoms, whose magnetic polarity is set by the hard disk’s read/write head to represent data as either a binary one or zero.</p>
<p>An alternative “bottom-up” method would involve constructing storage devices by placing individual atoms or molecules one by one, each capable of storing a single bit of information. Magnetic domains retain their magnetic memory due to communication between groups of neighbouring magnetised atoms.</p>
<p>Single-atom or single-molecule magnets on the other hand do not require this communication with their neighbours to retain their magnetic memory. Instead, the memory effect arises from quantum mechanics. So because atoms or molecules are much, much smaller than the magnetic domains currently used, and can be used individually rather than in groups, they can be packed more closely together which could result in an enormous increase in data density.</p>
<p>Working with atoms and molecules like this is not science fiction. Magnetic memory effects in single-molecule magnets (SMMs) were <a href="http://dx.doi.org/10.1038/365141a0">first demonstrated in 1993</a>, and <a href="http://dx.doi.org/10.1126/science.aad9898">similar effects for single-atom magnets</a> were shown in 2016. </p>
<h2>Raising the temperature</h2>
<p>The main problem standing in the way of moving these technologies out of the lab and into the mainstream is that they do not yet work at ambient temperatures. Both single atoms and SMMs require cooling with liquid helium (at a temperature of –269°C), an expensive and limited resource. So research effort over the last 25 years has concentrated on raising the temperature at which <a href="https://www.doitpoms.ac.uk/tlplib/ferromagnetic/hysteresis.php">magnetic hysteresis</a> – a demonstration of the magnetic memory effect – can be observed. An important target is –196°C, because this is the temperature that can be achieved with liquid nitrogen, which is abundant and cheap.</p>
<p>It took 18 years for the first substantive step towards raising the temperature in which magnetic memory is possible in SMMs – an increase of 10°C <a href="http://dx.doi.org/10.1021/ja206286h">achieved by researchers in California</a>. But now our research team at the University of Manchester’s School of Chemistry have <a href="http://dx.doi.org/10.1038/nature23447">achieved magnetic hysteresis in a SMM at –213 °C</a> using a new molecule based on the rare earth element dysprosocenium, as reported in a letter to the journal Nature. With a leap of 56°C, this is only 17°C away from the temperature of liquid nitrogen.</p>
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<h2>Future uses</h2>
<p>There are other challenges, however. In order to practically store individual bits of data, molecules must be fixed to surfaces. This has been <a href="http://dx.doi.org/10.1038/nmat2374">demonstrated with SMMs in the past</a>, but not for this latest generation of high-temperature SMMs. On the other hand, <a href="http://dx.doi.org/10.1126/science.aad9898">magnetic memory in single atoms</a> has already been demonstrated on a surface.</p>
<p>The ultimate test is demonstration of writing and non-destructively reading data in single atoms or molecules. This was achieved for the first time in 2017 by a group of researchers at IBM who demonstrated the <a href="http://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/single-atom-serves-as-worlds-smallest-magnet-and-data-storage-device">world’s smallest magnetic memory storage device</a>, built around a <a href="http://dx.doi.org/10.1038/nature21371">single atom</a>.</p>
<p>But regardless of whether single-atom or single-molecule storage devices ever become truly practical, the advancements in fundamental science being made along this path are phenomenal. The synthetic chemistry techniques developed by groups working on SMMs now allow us to design molecules with customised magnetic properties, which will have applications in quantum computing and even magnetic resonance imaging.</p><img src="https://counter.theconversation.com/content/82601/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr. Nicholas Chilton receives funding from the EPSRC, the Ramsay Memorial Trust and the University of Manchester.</span></em></p>Work to develop a single-atom magnet that works at room temperature has just taken a big leap forward.Nicholas Chilton, Research Fellow - School of Chemistry, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/750652017-03-31T01:59:31Z2017-03-31T01:59:31ZCloud, backup and storage devices: how best to protect your data<figure><img src="https://images.theconversation.com/files/163266/original/image-20170330-15619-l7vchv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How much data do you still store only on your mobile, tablet or laptop?</span> <span class="attribution"><span class="source">Shutterstock/Neirfy</span></span></figcaption></figure><p>We are producing more data than ever before, with more than <a href="https://www-01.ibm.com/software/data/bigdata/what-is-big-data.html">2.5 quintillion</a> bytes produced every day, according to computer giant IBM. That’s a staggering 2,500,000,000,000 gigabytes of data and it’s growing fast.</p>
<p>We have never been so connected through smart phones, smart watches, laptops and all sorts of wearable technologies inundating today’s marketplace. There were an estimated <a href="http://www.gartner.com/newsroom/id/3165317">6.4 billion</a> connected “things” in 2016, up 30% from the previous year.</p>
<p>We are also continuously sending and receiving data over our networks. This unstoppable growth is unsustainable without some kind of smartness in the way we all produce, store, share and backup data now and in the future.</p>
<h2>In the cloud</h2>
<p>Cloud services play an essential role in achieving sustainable data management by easing the strain on bandwidth, storage and backup solutions. </p>
<p>But is the cloud paving the way to better backup services or is it rendering backup itself obsolete? And what’s the trade-off in terms of data safety, and how can it be mitigated so you can safely store your data in the cloud?</p>
<p>The cloud is often thought of as an online backup solution that works in the background on your devices to keep your photos and documents, whether personal or work related, backed up on remote servers. </p>
<p>In reality, the cloud has a lot more to offer. It connects people together, helping them store and share data online and even work together online to create data collaboratively. </p>
<p>It also makes your data ubiquitous, so that if you lose your phone or your device fails you simply buy a new one, sign in to your cloud account and voila! – all your data are on your new device in a matter of minutes. </p>
<h2>Do you <em>really</em> back up your data?</h2>
<p>An important advantage of cloud-based backup services is also the automation and ease of use. With traditional backup solutions, such as using a separate drive, people often discover, a little too late, that they did not back up certain files. </p>
<p>Relying on the user to do backups is risky, so automating it is exactly where cloud backup is making a difference. </p>
<p>Cloud solutions have begun to evolve from online backup services to primary storage services. People are increasingly moving from storing their data on their device’s internal storage (hard drives) to storing them directly in cloud-based repositories such as <a href="https://www.dropbox.com">DropBox</a>, <a href="https://www.google.com/drive/">Google Drive</a> and Microsoft’s <a href="https://onedrive.live.com/about/en-au/">OneDrive</a>.</p>
<p>Devices such as Google’s <a href="https://www.google.com.au/chromebook/">Chromebook</a> do not use much local storage to store your data. Instead, they are part of a new trend in which everything you produce or consume on the internet, at work or at home, would come from the cloud and be stored there too. </p>
<p>Recently announced cloud technologies such as <a href="https://www.blog.google/products/g-suite/introducing-new-enterprise-ready-tools-google-drive/">Google’s Drive File Stream</a> or <a href="https://www.dropbox.com/business/smartsync">Dropbox’s Smart Sync</a> are excellent examples of how cloud storage services are heading in a new direction with less data on the device and a bigger primary storage role for the cloud. </p>
<p>Here is how it works. Instead of keeping local files on your device, placeholder files (sort of empty files) are used, and the actual data are kept in the cloud and downloaded back onto the device only when needed. </p>
<p>Edits to the files are pushed to the cloud so that no local copy is kept on your device. This drastically reduces the risk of data leaks when a device is lost or stolen.</p>
<p>So if your entire workspace is in the cloud, is backup no longer needed?</p>
<p>No. In fact, backup is more relevant than ever, as disasters can strike cloud providers themselves, with hacking and ransomware affecting cloud storage too. </p>
<p>Backup has always had the purpose of reducing risks using redundancy, by duplicating data across multiple locations. The same can apply to cloud storage which can be duplicated across multiple cloud locations or multiple cloud service providers. </p>
<h2>Privacy matters</h2>
<p>Yet beyond the disruption of the backup market, the number-one concern about the use of cloud services for storing user data is privacy. </p>
<p>Data privacy is strategically important, particularly when customer data are involved. Many privacy-related problems can happen when using the cloud. </p>
<p>There are concerns about the processes used by cloud providers for privacy management, which often trade privacy for convenience. There are also concerns about the technologies put in place by cloud providers to overcome privacy related issues, which are often not effective. </p>
<p>When it comes to technology, encryption tools protecting your sensitive data have actually been around for a long time. </p>
<p>Encryption works by scrambling your data with a very large digital number (called a key) that you keep secret so that only you can decrypt the data. Nobody else can decode your data without that key. </p>
<p>Using encryption tools to encrypt your data with your own key before transferring it into the cloud is a sensible thing to do. Some cloud service providers are now offering this option and letting you choose your own key. </p>
<h2>Share vs encryption</h2>
<p>But if you store data in the cloud for the purpose of sharing it with others – and that’s often the precise reason that users choose to use cloud storage – then you might require a process to distribute encryption keys to multiple participants. </p>
<p>This is where the hassle can start. People you share data with would need to get the key too, in some way or another. Once you share that key, how would you revoke it later on? How would you prevent it from being re-shared without your consent?</p>
<p>More importantly, how would you keep using the collaboration features offered by cloud providers, such as Google Docs, while working on encrypted files?</p>
<p>These are the key challenges ahead for cloud users and providers. Solutions to those challenges would truly be game-changing.</p><img src="https://counter.theconversation.com/content/75065/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adnene Guabtni does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We have never been so connected and we are producing more data than ever before. But how can we manage our data effectively while making sure it remains safe?Adnene Guabtni, Senior Research Scientist/Engineer, Data61Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/504742015-11-11T10:40:17Z2015-11-11T10:40:17ZSound waves could power hard disk drives of the future<figure><img src="https://images.theconversation.com/files/101455/original/image-20151110-21201-xh7uy.jpg?ixlib=rb-1.1.0&rect=4%2C5%2C693%2C472&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tiny surface acoustic waves are enough to carry data quickly. </span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:TeO2SAWs.jpg">Femtoquake</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Our need to store data is growing at an astonishing rate. An estimated <a href="http://www.forbes.com/sites/ciocentral/2012/05/01/big-data-the-hidden-opportunity/">2.7 zettabytes (2.7 x 10<sup>21)</sup> of data</a> are currently held worldwide, equivalent to several trillion bytes for every one of the 7 billion people on Earth. Accessing this data quickly and reliably is essential for us to do useful things with it – the problem is, all our current methods of doing so are far too slow. </p>
<p>Conventional hard-disk drives encode data magnetically on spinning discs, from which the data is read by a sensor that scans over its surface as it rapidly rotates. Their moving parts introduce the potential for mechanical failures, and limits the speeds possible. This slows everything down.</p>
<p>Much faster are solid-state storage devices, which have no mechanical parts and store data as tiny electrical charges. Most modern laptops, all modern smartphones and digital cameras, and many other devices use this technology – also known as <a href="http://computer.howstuffworks.com/flash-memory.htm/printable">flash memory</a>. However, while solid-state devices are much faster they have a much shorter lifespan than hard disks before becoming unreliable, and are much more expensive. And despite their speed, they’re still far slower than the speed at which data travels between other components of a computer, and so still act as a brake on the system as a whole. </p>
<p>A solid-state drive that encodes data magnetically would be ideal. IBM is developing one variation, known as <a href="http://www-03.ibm.com/ibm/history/ibm100/us/en/icons/racetrack/">racetrack memory</a>. This uses collections of tiny nanowires hundreds of times thinner than a human hair. Data is magnetically encoded as strings of ones and zeros along the nanowire, but although it can move data through it far faster than typical hard disks, a key challenge is to find ways to make the data “flow” through the nanowires in order to pass it across the sensors that read and write data to the wire. This can be achieved by applying magnetic fields or electric currents, but this generates heat and reduces power efficiency, affecting battery life.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/101484/original/image-20151110-21190-ojbiwg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Electrical current can provide flow for racetrack memory, but at the cost of heat and inefficiency.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>There are other ways of moving magnetic data, however. My group at the University of Sheffield in conjunction with John Cunningham at the University of Leeds have been using simulations, <a href="http://scitation.aip.org/content/aip/journal/apl/107/14/10.1063/1.4932057">now published in Applied Physics Letters</a>, to explore ways of making racetrack memory more efficient and stumbled upon a surprising solution using sound waves.</p>
<h2>Moved by the sound</h2>
<p>In our simulations we created vibration-sensitive magnetic nanowires on top of layers of piezoelectric materials, which stretch when we apply an electric voltage. By applying a rapidly-switching voltage they begin to vibrate, creating a special sort of sound wave known as <a href="http://www.sp.phy.cam.ac.uk/research/fundamentals-of-low-dimensional-semiconductor-systems/saw">surface acoustic waves</a>.</p>
<p>Using this method we created two sound waves, one flowing forwards along the nanowires and one flowing backwards. These waves combine together to create regularly spaced regions of the nanowire which vibrate strongly separated by regions that don’t vibrate at all. <a href="http://scitation.aip.org/content/aip/journal/apl/107/14/10.1063/1.4932057?utm_source=tech.mazavr.tk&utm_medium=link&utm_compaign=article">Our research shows</a> that the magnetic data bits are attracted to and held in place at the strongly vibrating sections. If we then change the pitch of two sound waves, so that one “sings” a higher note and one a lower note, we find that vibrating regions start to flow along the nanowire, pulling the data bits with them just as is required for racetrack memory. If we switch the notes around, the data flows in the opposite direction. Using only sound alone it’s possible to move data in both directions.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/101485/original/image-20151110-21201-1sqavc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Using sound waves to provide an energy efficient flow for racetrack memory.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>At the moment our simulations show data flowing at around 100mph (160kph). This sounds pretty fast, but we’d like it to be ten times faster. However the really exciting implications of this stem from the unique properties of surface acoustic waves. Because they only exist right at a material’s surface they lose energy very slowly, and can travel as much as several centimetres (which is huge when you consider the tiny size of the nanowires). Because nanowires are so small a single pair of waves could be applied to a very large number of wires, and therefore the data within them, at the same time. Potentially this makes it a very power efficient way of moving lots of data around quickly.</p>
<p>There are still a lot of questions that need answering before we’ll know whether this technology is really the solution to the problems holding back racetrack memory. But with these promising initial indications, the next step is to create an experimental prototype to test it for real.</p><img src="https://counter.theconversation.com/content/50474/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Hayward receives funding from the Engineering and Physical Research Council and the Royal Society.</span></em></p>After electric and magnetic fields, nanoscale sound waves are a new idea for data storage.Tom Hayward, EPSRC Career Acceleration Research Fellow, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/173862013-08-23T04:29:12Z2013-08-23T04:29:12ZExplainer: how do you destroy a hard drive?<figure><img src="https://images.theconversation.com/files/29766/original/c4qkxgc2-1377207337.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hope they backed it up ...</span> <span class="attribution"><span class="source">purplemattfish</span></span></figcaption></figure><p>Anyone who looked at The Guardian’s website this week will have seen a picture of one of the newspaper’s own laptops <a href="http://www.theguardian.com/world/2013/aug/20/nsa-snowden-files-drives-destroyed-london">smashed and in pieces</a>. </p>
<p>Why did this Mac have to die? The article accompanying the photo describes how The Guardian was visited by representatives of GCHQ who, believing The Guardian were using the laptop in question to store files provided by the NSA whistleblower Edward Snowden, demanded that the data on it should either be handed over to them, or destroyed. </p>
<p>The fragments of computer pictured on The Guardian’s website make it clear that they chose the second option. Leaving aside the rights and wrongs of an intelligence agency interfering with journalists, and the fact that electronic data is very easily replicated, was it really necessary to smash up a computer in order to make sure the data was really gone? Well, truly deleting data might be harder than you think. </p>
<p>A standard computer will store your files on a “hard drive”; specifically a stack of spinning disks coated in a magnetic film. This film acts like billions of tiny magnets, each of which can be in one of two positions, representing either a one or a zero. All of your files: documents, pictures, music and movies, are encoded on these disks as sequences of ones and zeros. To keep things organised, the hard drive has a table of contents that indicates which parts of the drive are currently in use and where each file is stored. </p>
<p>Deleting a file only deletes the file’s information from the drive’s table of contents; the ones and zeros that make up the file remain on the drive. Until this data is overwritten, it is easy enough to look at this ghost data and reconstruct the file. An <a href="http://www.computerworld.com/s/article/9127717/Survey_40_of_hard_drives_bought_on_eBay_hold_personal_corporate_data?pageNumber=1">analysis</a> of second hand hard drives from eBay found 40% contained personal information that could be recovered in this way.</p>
<p>A more sophisticated method of removing a file is to repeatedly overwrite the file data with random values and then delete it. This is the standard method of “securely deleting” files used by many businesses. There are many free applications that will do this for you on Windows (for example, <a href="http://eraser.heidi.ie">Eraser</a>); on a Mac this can be done via the “Securely Empty Trash” option on the finder menu and on Linux you can use the “shred” command. </p>
<p>But even this isn’t guaranteed to destroy the data completely; when viewed under a magnetic force microscope, a tiny magnet on the drive that has recently been switched from a 1 to a 0 will look slightly different to one that has been in the 0 position for a long time. Therefore, with a well-equipped lab, it may still be possible to reconstruct the deleted data. A further complication is that it would have been hard for The Guardian to prove to GCHQ that this procedure had been carried out correctly; showing GCHQ the smashed pieces of a hard drive would certainly have provided more conclusive evidence. </p>
<p>Smashing a hard drive is a sure way to stop it functioning as intended (step-by-step instructions on physically destroying a hard drive can be found <a href="http://www.wikihow.com/Destroy-a-Hard-Drive">here</a>). Companies that specialise in the mass destruction of data will put hard drives through an <a href="https://www.youtube.com/watch?v=sQYPCPB1g3o">industrial shredder</a>. But even this may not be enough to ensure the data really is unreadable. Each fragment of disk will still contain the ones and zeros that represent the files, and so with advanced lab equipment they could be read and pieced back together. The Guardian reports that they used angle grinders to destroy their drive, which would have probably fragmented it into pieces too small to read. In which case, we can be sure that the data on the laptop in question is gone.</p>
<p>Justified or not, the complete destruction of The Guardian’s hard drive was the only sure way to be certain that the data was really gone, but many questions remain. For example, the pictures on the Guardian’s website only showed the smashed case and main computing boards, not the computer’s memory and hard drive. So what happened to the actual hard drive that stored the data? Why were parts of the computer that hold no data also smashed? </p>
<p>It’s unlikely that The Guardian or GCHQ will be providing answers to these questions anytime soon. So that leaves us with one final question (originally posed by security expert <a href="https://twitter.com/mattblaze">Matt Blaze</a>): does an AppleCare warranty cover the destruction of a computer due to interference by the secret services? Let’s hope so, because it looked like a nice laptop. </p><img src="https://counter.theconversation.com/content/17386/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Chothia does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Anyone who looked at The Guardian’s website this week will have seen a picture of one of the newspaper’s own laptops smashed and in pieces. Why did this Mac have to die? The article accompanying the photo…Tom Chothia, Lecturer in Computer Science, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.