Author: David Bradley

A review of the state-of-the-art in optical storage technology from Sony scientists caught my eye while I was data mining journal ToC feeds recently. The demise of the Toshiba HD DVD format and the emergence of Sony’s Blu-Ray as the winner has been this decade’s equivalent of the VHS-Betamax face-off of the 1980s.

While many commentators point out that other technologies, such as solid state storage are waiting in the wings white-out optical, the Sony team sees growth lying ahead and the development of a CD-sized holographic disk that can store several terabytes of data available to the consumer realm.

Writing in a forthcoming issue of the International Journal of Product Development (2008, 5, 447-454), Toshiharu Okanishi, Toru Takeda, and Mamoru Nishio of the Technology Strategy and Development Department, at Sony Corporation, in Tokyo, Japan, point out that the “pit-by-pit” optical recording and reading technology used initially in the CD, then the DVD and more recently with sharper blue-purple lasers will see continued growth in one form or another. However, there will be no significant jumps in the near future, they say. There will be some significant improvement with the emergence of so-called near-field recording and super-resolution near-field recording, which will push the boundaries of what is possible with pit-by-pit to data densities.

Data storage technology, whether IBM’s magnetic disks of the 1970s, which are still with us, or the 1980s optical technology pioneered by Philips, is an enormous market. Magnetic hard drives – the Winchester technology – have progressed from disks of a few megabytes to the multi-platter terabyte beasts of today, total annual market is estimated at US$25 billion. In contrast, optical represents a market of $10b, but with rewritable disks adding some $3b each year to that total.

The Sony team offers a cosy view of the Winchester and Optical partnership:

Both technologies and both businesses have been developed back-to-back for the last 25 years and they will go hand-in-hand into the future, too.

While R&D in magnetic disks has continued apace, the technology remains locked pretty much in the 1970s. That said, storage and reliability of grown enormously and disks got much smaller since the early days. Nevertheless, new ways to make optical disks, to code and decode them and to ensure error correction have pushed the partner technology forward rapidly too. The development of high-frequency semiconductor lasers was key to the progression from CD (several hundred megabytes) to Blu-Ray disks that can store 25 gigabytes on a single layer. And almost as an aside there is Ultra Density Optical (UDO) storage from Plasmon, which uses highly precise tracking to increase the data density and allows 120 and 240 Gb capacities.

The Sony team points out that the technology that makes optical storage possible – the semiconductor lasers that read-write the disks, encoding and decoding systems, and the error correction systems have pretty much converged. With such a state of affairs there is little room for a significant jump in bit-by-bit optical storage in the near future. They also assert that there is room in the market for a mere ten percent increase in volume sales. Both factors coupled with falling revenues will reduce R&D spending still further. A paradigm shift could be the only change that could drive the industry forward – holographic disks could represent just such a shift.

It’s a paradigm shift whose time is long overdue, however. The concept of holographic recording was proposed way back in the 1970s and such systems have been used for decades for high-level purposes on incredibly expensive systems for companies and organisations that need to store vast amounts of data.

It took a significant development in chemistry, the invention of photo-polymer recording materials, before researchers could foresee a practical way to implement holographic recording. Okanishi and colleagues emphasise that holographic recording is a totally different approach compared to other optical storage systems, but requires a shift in the costly precision technology currently available to bring it to the mainstream consumer.

First off, there are two types of hologram possible – thin film and volume. With a volume hologram device used for large data storage purposes it is possible to store different pieces of data on the same area of the data medium, that is at different depths instead of a single layer (as in a CD) within a cone-shaped volume. Indeed, prototype systems promise storage of 60000 bits per pulse in a single 3D pit on a disk the same size as a CD. “This means the total capacity of a package is basically proportional to the three-dimensional volume of the medium,” the researchers explain. The team points out that to make such a system work well requires coherent optimisation of different parts of the technology in parallel.

The Holographic Versatile Disc (HVD) format utilises two lasers – a red and a green which are piped into a single pulse of light. The green laser picks up data from interference patterns in a holographic layer, while the red acts as a control or reference beam. The potential is for a system with a capacity of almost 3.9 terabytes (39000 gigabytes), which is nearly 6000 times as much data as can be stored on a CD, hundreds of times a DVD. Costs will initially make HVD inaccessible to most consumers with drives costing tens of thousands of dollars and the disks themselves at least a couple of hundred dollars. As with most technology, prices will fall as the market matures. “I am not sure which (consumer or professional) market HVD is currently aiming,” Okanishi told Sciencebase, “But it is a good challenge to gather industrial eyes to this prospective technology.”

The other benefits of HVD over DVD will be data transfer rates, with speeds some six times faster. Such speeds will be quite useful if one is carrying out file transfers with the entire US Library of Congress (storable on just 6 HVDs), the whole of Google Earth data (2 disks) or 12000 hours of mpeg files (that’s a year’s continual viewing).

There are various companies working on HVD, including Optware (site offline), InPhase Technologies (also offline) and its patented Tapestry Media, Hitachi Maxell Ltd. Other companies and more information can be found on the HVD Forum

News headlines almost always deal in data-free absolutes. Take this recent strapline from an item on Australian news site: Drinking two or more colas a day – whether sweetened with sugar or an artificial sweetener – doubles your risk of chronic kidney disease, according to new research. And, at the time of writing, the media is full of the news that modern antidepressants don’t work, although the actual research papers on which such headlines are based will not be quite so definitive in their conclusions.

It is fairly typical of the many health stories that cross the news wires on a daily basis, if it isn’t artificial sweeteners, sugars, fat, and cholesterol, then it’s organic pollutants, prescription drugs, and electromagnetic radiation. The headlines seem inevitably to contrast starkly with the output of government and industry that seeks to quash our fears and to emphasise how doubling a tiny, tiny risk is no big deal.

It is not just health scares that are problematic. Similarly, we are repeatedly warned of the dangers of this or that behaviour, the effects on our lives of multifaceted issues, such as pollution, the changing climate.

It is difficult to disentangle the cause from the effect. Is the growing number of scare stories feeding a healthy public scepticism of technology or does it simply feed on a reluctance to trust technical expertise and science? It’s a problem for those in science and technology who face repeated impediments to their work that are more often than not based on unfounded qualms and misrepresented statistics.

There have been industrial accidents, of course, humans are indeed exposed to new chemicals, ecological systems do get harmed, and there are uncertainties about biological advances such as genetically modified organisms and nuclear power.

Writing in the International Journal of Global Environmental Issues (2008, 8, 132-146) social scientist Elisabeth Graffy and civil engineer Nathaniel Booth of the US Geological Survey, in Middleton, Wisconsin, argue that it should be possible to instil the public with renewed confidence in the validity of risk assessment as well as improve the outcomes of risk assessment. They suggest that this will require a reframing of risk research and communication so that scientific knowledge evolves in parallel with public understanding rather than the two being entirely disjointed. While the approach they propose is not likely to eliminate the type of see-saw headlines we see every day, it could have an effect on at least some issues.

Graffy and Booth report on a web-based platform that was developed to link experts and public discourse through shared information resources. Such a site “could simultaneously foster greater public awareness of the links between environmental and human health vulnerabilities, advances in scientific evaluation and assessment,” they explain, and lead to improved communication between the two. The prototype system, they add, was well received by scientists and public alike.

However, the researchers concede that there is much room for improvement in their web-based approach, if the goal is to reach the general public. In their experiment, it was the policy makers at different levels who got the most from it whereas the impact on general public users was mixed. The research of communications professors Craig Trumbo of Colorado State University, in Fort Collins, Colorado, and Katherine McComas of Cornell University, in Ithaca, New York, reported in the same issue of the journal (2008, 8, 61-76) point out that there are many intrinsic difficulties in engaging the public with sci-tech matters, particularly when health or environmental risks are involved.

They have looked at how public trust of institutions, whether of governments, companies or other organisations affects the way in which people process information and perceive risk. Their data are based on US state health department investigations into 30 suspected cancer clusters. The researchers assessed trust for three information sources: state health departments, civic groups and the industries involved in each case.

Perhaps unsurprisingly, Trumbo and McComas found that when people have trust in the state health department’s information their perception of risk is lower, while trust of civic groups, often activist groups, is associated with the perception of greater risk.

But, the situation is not quite that clear cut. “The manner by which these associations may form is linked to the way that people process the information, ” Trumbo told Sciencebase, “Trust associated with civic groups, for example, is aligned with having to use a systematic strategy for information processing. This is a more effortful and involved processing form. Conversely, trust associated with industry or state sources is aligned with stronger heuristic information processing. This is a less effortful and more “rule of thumb” manner of thinking.”

“Trust is a precious commodity for those communicating risk and perhaps acutely so for industry and governmental risk communicators who are typically considered ‘less trustworthy’ sources,” the researchers say.

It could be that the underlying problem, the disparity between the purported trustworthiness of civic, state and industry sources involves public understanding of science, the scientific process, and what is scientific evidence and what is not. But it is also recognized that science itself is not a value-free enterprise and that in many contexts, especially cancer clusters, there is a high degree of uncertainty even for the scientists. In these contexts it is unlikely that there is much to be gained by making the assumption that if we might only educate people about science they will arrive at the correct opinion about risk. These contexts call for a balanced approach to risk communication that recognizes the key difference between data-free absolutes, pseudoscientific opinion, legitimate value-based non-expert reactions, and the role of a scientific approach in risk assessment, Trumbo explains.

In a follow-up article, I will be discussing my experience of asking for feedback on the issue of public trust in science on the business networking site LinkedIn. Watch this space, or better still subscribe to the Sciencebase newsfeed and ensure you don’t miss it. My item on Trust is now scheduled to post March 24, 2008.