n°28I quarterlyI January 2013 Focus | 27 sTorAGE soluTIons Magnetic hard disks remain the most 10 widespread medium for storing the exponential flow of data. A hard disk drive contains a set of glass or metal discs spinning at high speed (usually 7200 RPM) inside a sealed case. Each disc is covered with a magnetic layer where the data is recorded. Today, commercial hard disks store around 15 gigabytes per square centimeter, a figure that may double by 2016. Besides, hard disks offer much better performance than either optical discs (CDs and DVDs) or “holographic optical” discs which are struggling to enter the mass market. Meanwhile, hard disk prices have plummeted. When IBM presented its first incarnation in 1956, it cost €8 million to store one gigabyte, compared to a few euro cents today. As a result, magnetic tape, which is ten times cheaper, is the only technology that can compete on price. Tapes have a major drawback, however: they are slow and therefore can only serve to store infrequently-used data. Finally, flash memory, the storage technology found in most mobile devices, is becoming increasingly popular. It reads data faster than hard disks, and its price/performance ratio is shrinking fast. © 10 a 10,000 m2google for Google Apps and Apple’s iCloud, de- datacenter located 11 signed for consumer services such as incouncilbluffs, computers, tablets, or smartphones. This Iowa (us). 11Facebook will set solution is cost-effective for consumers, up a datacenter in who only pay for what they need. But it sweden in order to also has a drawback: “These services may optimize cooling be attractive to companies for non-stra- (artist’s rendition). tegic data, but it is difficult to fully trust the system. Amazon has already had a a IP failure so massive that data could not be asP/ recovered,” Valduriez points out. © ments), a successful attack can cause a lot on a completely different tack: “The EU hIGhsECurITynEEDs of damage,” notes Hubert Comon-Lundh, recently initiated legislative reform to These concerns are slowing the develop- who works on computer protocol security reinforce protection of data pertaining to ment of cloud computing. “Many compa- at the LSV3 in Cachan. To counter this its businesses and citizens,” notes nies are reluctant to use it for confidenti- threat, research has focused on detecting Valduriez. This political choice could well ality reasons,” explains Véronique Cortier attacks before they occur and on creating help Europe catch up with the Americans of the LORIA.2 “Most of the time, servers data silos to compartmentalize informa- in the cloud. store data in a legible format, making it tion. In Europe, the issue of data security 01.laboratoired’informatique,derobotiqueetde accessible to any employee who manages and confidentiality is all the more impor- microélectroniquedeMontpellier(cnrs/université Montpellier-II). the server.” To solve this problem, data tant since suppliers such as Amazon and 02.laboratoirelorrainderechercheeninformatiqueet must be encrypted on the client system Google are American corporations and Inria). (cnrs/universitédelorraine/applicationsses before it is sent to the cloud. “Research is therefore subject to the Patriot Act. This 03.laboratoirespécificationetvérification(cnrs/ens cachan). underway to develop such a solution. But law, adopted by the US Congress follow- it makes data access more complex and ing the September 11 attacks, gives the increases calculation time—and cost.” federal government the right to access contactInFormatIon: There is another weakness: clouds data hosted on the server of any American hubert Comon-lundh provide a central point of entry making company, wherever the server is located. véronique Cortiercomon@lsv.ens-cachan.fr> them vulnerable to piracy. “Since many This extra-territorial right of access is > veronique.cortier@loria.fr sites use a single access control for all worrisome and seems to be holding back > patrick.valduriez@lirmm.fralduriezvPatrick their services (email, calendars, docu- European users. The European Union is
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