Imagine being able to put 27 copies of a film like The Matrix onto a single disc no larger than a DVD. This massive increase in storage was the carrot that tempted audiences at CeBIT to a presentation given by George Purrio, technical manager at storage firm Imation last week.
Lucent's Bell Labs has been pioneering a technique to store vast quantities of data as a three-dimensional hologram. According to a white paper on the subject from Imation, first generation holographic drives could have the potential to store 125Gbytes of user data on a removable 5.25in disc. This is equivalent to 27 4.7Gbyte DVDs.
Moreover, holography promises faster transfer rates and access time to data. Million-bit pages of data can be stored and recovered in parallel and some non-mechanical access techniques permit sub-millisecond access.
The transfer rates would be about 25 times faster than that of DVD. Future generations of devices are expected to be able to store a terabyte on a single disc, with about 150 times the transfer rates of current DVDs.
A key application for such devices is data warehousing, which requires massive storage capacity. Current mass storage technologies allow 20 to 30 weeks of data to be stored and analysed. But, according to Imation, future holographic mass memories could enable several years' worth of information to be stored in a data warehouse and cross-correlated.
In holographic storage light from a laser is split into two beams - the signal which carries data (such as the binary representation of a photograph) and a reference beam, which works with the signal to generate a holographic pattern of the data.
The vast potential of holographic memory is made possible by "multiplexing". This involves storing multiple holograms effectively in the same place by changing some characteristics of the reference beam. For instance, each hologram could be stored at a unique angle within the storage medium.
According to Imation, researchers have been able to build experimental holographic mass storage systems using off-the-shelf optics, which reduces the price of the equipment, and it estimates that removable media will cost considerably less than $10 per disc.
Imation is also confident that first-generation holographic mass storage drives will be able to store 125 gigabytes of user data on a removable 5.25in disc, with read rates greater than 30mbps.
This was first published in March 2000