Hard discs are the real engines of the computer revolution. More than rising processing speeds, it is constantly expanding hard disc capacity that has made most of the exciting recent developments possible.
This is most obvious in the case of Google, which now not only searches most of the Web, and stores its (presumably vast) index on cheap hard discs, but also offers a couple of Gbytes of storage to everyone who uses/will use its Gmail. Greatly increased storage has also driven the MP3 revolution. The cheap availability of Gigabytes of storage means that people can - and so do - store thousands of songs, and now routinely expect to have every song they want on tap, instantly.
Yet another milestone was reached recently, when even the Terabyte (=1,000 Gbytes) became a relatively cheap option. For most of us mere mortals, it is hard to grasp what this kind of storage will mean in practice. One person who has spent a lot of time thinking hard about such large-scale storage and what it means is Jim Gray, whom I had the pleasure of interviewing last year.
On his Web site (at Microsoft Research), he links to a fascinating paper by Michael Lesk that asks the question How much information is there in the world? (There is also a more up-to-date version available.) It is clear from the general estimates that we are fast approaching the day when it will be possible to have just about every piece of data (text, audio, video) that relates to us throughout our lives and to our immediate (and maybe not-so-immediate) world, all stored, indexed and cross-referenced on a hard disc somewhere.
Google and the other search engines already gives us a glimpse of this "Information At Your Fingertips" (now where did I hear that phrase before?), but such all-encompassing Exabytes (1,000,000 Terabytes) go well beyond this.
What is interesting is how intimately this scaling process is related to the opening up of data. In fact, this kind of super-scaling, which takes us to realms several orders of magnitude beyond even the largest proprietary holdings of information, only makes sense if data is freely available for cross-referencing (something that cannot happen if there are isolated bastions of information, each with its own gatekeeper).
Once again, technological developments that have been in train for decades are pushing us inexorably towards an open future - whatever the current information monopolists might want or do.