In the last of Click Online's series on computer data storage, Spencer Kelly takes a look at what projects experts are currently looking at.
We just cannot get enough storage space.
Holographic solutions of the future could look rather like a sugar cube
All of the well established storage methods are evolving to accommodate our needs.
They are becoming more compact and taking on more data, even as developers are planning the next generation, and the one after that.
For example, even as the latest generation of spinning optical disk is being launched - with the new blue laser disks instead of red, and holding as much as 25 GB per layer - some experts are already planning a successor.
Optical disks holding hundreds of hours of television are even now on the drawing board.
Dr Peter Török, of Imperial College, London, says: "Blu-Ray disks are the next generation after DVDs. They will be able to store 25 GB per layer.
"We are trying to do an increment of at least five times that."
Small is beautiful
A CD works by having 1s and 0s which are stored as bumps that deflect or reflect a laser beam.
But Dr Török's disk player would not just pick up a deflection; it would also measure the angle that the laser is deflected.
Now, instead of just a 1 or 0, each bump can be used to store much more data.
Of course, in the world of technology, small is the new big.
The ultimate engineering challenge is to fit everything into a truly tiny space.
Futurologist Adrian Mars says: "The holy grail is to get to the same sort of scales that the human body is built on - that's individual molecules doing sensible things.
"So the great leap forward recently made by Hewlett-Packard is to lay - at the intersections of wires - almost single molecules.
"They are down to about 1,000 molecules. These respond to the current going from one wire to another and can be flipped from one state to another."
Manipulating individual molecules as bits of data, on a nanoscale, is still the stuff of lab research.
But developers are confident that before too long we will have a wealth of nanoscale storage devices at our disposal.
A postage stamp-sized Millipede system could hold 600,000 images
One such method, currently in development, is called Project Millipede.
IBM's Dr David Watson says: "Millipede uses a grid of 80x80 stylus-like pins, which are extremely small, to punch holes into a polymer surface.
"This is a read/write technology, so you can write a hole as a 1 and then pop it back out as a 0.
"This offers fantastic storage potential.
"A single Millipede device could hold something in the order of 600,000 digital camera images on something the size of a postage stamp."
Most storage methods of today store data in one long line, such as a reel of tape or the spiral track on a CD.
These are really only one-dimensional.
Some, like Flash memory and the forthcoming Millipede, store data across a two-dimensional surface.
Some projects in the pipeline go even further, stacking data in three dimensions.
Twenty years ago, holograms were the must-have art to hang on the wall: three-dimensional pictures stored inside a seemingly two-dimensional photograph.
One thing is certain: we are always going to need more storage
It turns out data can be stored in a similar way.
Adrian Mars says: "Holographic storage is essentially writing images - holograms - into a sugar cube-sized block.
"The plan is that you'll be able to get at least a terabyte of information into a single sugar cube.
"Obviously it's not made of sugar! Experiments so far have used either a light-sensitive polymer or a special light-sensitive crystal."
It has become staggeringly easy to zap spots inside a crystalline structure.
Of course, all of these new and emerging technologies still face hurdles, and not all will make it to market
But one thing is certain: we are always going to need more storage, and the storage devices we will use in the future may look very strange indeed.
Click Online is broadcast on BBC News 24: Saturday at 2030, Sunday at 0430 and 1630, and on Monday at 0030. A short version is also shown on BBC Two: Saturday at 0645 and BBC One: Sunday at 0730 . Also BBC World.