There are three things that nobody can ignore: the rising of the sun, the changing of the seasons and Oracle announcing a new product. This time, it's Oracle 10g -- where g stands for grid. Just like the Enterprise, the company proclaims it is boldly going where no-one's gone before. But just like Kirk, wherever Captain Ellison goes, there's always someone there already.
Grid computing is so called as an explicit metaphor to electric power: you don't know where your power comes from when you turn on the light, nor do you care. It's perhaps not the most felicitous of comparisons at the moment, with London and New York both graphically aware of just how dark it gets when the grid goes down and you've no local resources. But the principle's sound: arrange for any computer on your network to accept processing tasks from any other, and spare capacity can quickly be put to use when you need it.
There's nothing particularly revolutionary about the idea. It's closely related to the standard way you build supercomputers these days, with sweating rows of processors chained to the oars of computation as they sail oceanic quantities of data. Grid computing isn't as tightly coupled as massively parallel systems, but it does require co-ordination and management of many remote resources. It's also inherently robust. Providing the network stays up, you can easily map a request to a spare node if the one you're using stops working.
All this gets you a rather attractive set of features: high powered management tools, inherent reliability and tons of otherwise spare computing power being put to good use. It's not all gravy, however. The reason that grid computing hasn't taken world by storm is that it's only really useful for certain classes of application. So far, those have been big science and engineering tasks, where enormous amounts of data can be partitioned out and chomped through over time. If you need to do lots of very different things to lots of data very quickly, the overhead of parcelling the instructions and data out then getting the results back makes the process unattractive compared to more centralised processing. Grid computing straddles the spectrum of processor usage, with the single-user, single CPU PC sitting quietly at one end, multiprocessor systems in the middle, and massively parallel magic at the other. Grid is a nice mix of them all, but it's not scooting off into a whole new dimension.
You might not know this if you listen to Oracle. Oracle has always been quick to highlight the similarities between what it does and grid computing, but this time the company's got religion -- and they're praising grid to the skies. Oracle's new 10g database technology is all about grid, and with typical marketing flair -- some might say overarching hyperbole -- this means that everything's all about grid.