Comment General Electric has been talking up its holographic storage technology again, reckoning it can succeed where Plasmon and others have failed, because of backward Blu-ray and DVD compatibility.

Currently holographic storage products inhabit a graveyard or deep freeze. InPhase is currently seemingly in hibernation - not dead but showing little sign of life - though with a late 2009 ship date coming for its troubled $18,000 Tapestry drive and $180 per CD-size disks. UDO developer Plasmon is dead and gone, with a slight phoenix possibility in the shape of its asset purchaser, AST.

Why does GE think it has a chance of making it with a storage technology that has dashed so many hopes already? There seem to be three reasons: better recording and reading technology, insufficient Blu-ray capacity, and backwards compatibility.

Holographic storage involves holograms, images of data, being stored in layers in a CD-sized disk's recording surface. The images are created by two laser beams and read by a laser beam. GE's researchers at its Applied Optics Laboratory managed to shrink these images, calling them micro-holograms. They achieved this to the point where the images were also reflective enough - 200 times more so than before - to be read by optics that could be used to read existing optical formats. A CD-size disk could store 500GB using this technology, with 1TB and greater capacity potentially possible in the 2011/2012 period.

This compares to InPhase's 300GB capacity, although InPhase has predicted a ramp up through 800GB to a 1.6TB capacity point and a 120MB/sec transfer rate. This was said to be appearing in 2010, but that was in 2007, so we'd better assume a 2012/2013 date if InPhase holds to its course. There is a deal of overlap here between GE and Inphase capacities and capacity roadmaps.

The 500GB capacity equals ten double-layer, 50GB Blu-ray disks, or 100 5GB DVDs. GE believes that drives using its technology could also read Blu-ray, DVD and even CD disks. This makes them, in theory, usable by consumers and thus increases their volume dramatically, compared to the professional archiving market addressed by Plasmon's UDO and the InPhase Tapestry development. This volume should enable a per-drive cost far lower than the $18,000 InPhase has suggested for its Tapestry.

We should bear in mind that GE is suggesting that consumer drives using its technology wouldn't appear until 2014 or 2015, though, suggesting that drive cost will be a problem in the early years.

Company representatives suggest that an entire 3D movie might be storable on a disk with its technology.

There is the implicit assumption here that downloading such movies will not be feasible, as network links will be too slow. Another assumption is that Blu-ray capacity will simply not be enough for the massive files needed by 3D movies and the like in a few years time. Blu-ray will run out of capacity by 2013 or so, according to this scenario.

The GE drive technology has a 3msec access period and transfers data at what is described as five times the DVD transfer rate. Assuming a 16x DVD writer runs at 21.13MB/sec, this implies 105.65MB.sec. At that speed, a 1TB GE technology disk would take 2.65 hours to write. However, GE says its disks could be replicated off a golden master in a factory at rates of 180 to 360 an hour.

Cost-wise, GE is suggesting 10 cents/GB or less for disk capacity when the drives and disks are introduced, as hopefully expected, in 2011/2012. At $0.10/GB, a 1TB disk would cost $100: far, far from cheap.