This article copied over from MacWorld talks about the Solid State Disk (SSD) that's an option on the new MacBook Air. There's a little more depth than in the post I made 10 days ago.

The details about the new disk are simple. You pay an extra $1000, you get a smaller disk than on the lower price model. Why would you do that? To get a solid state disk that takes almost no energy to run, and is about 10 times more resistant to bumps and bangs. And, oh yes, helps your system boot much faster. Fast bootup makes an electronic device much handier.

I have an old AlphaSmart 2000 keyboard that uses an SSD of sorts. Well, the entire memory for the keyboard device (a dedicated text processor) is only about 256KB (yes, that's KB, not MB or GB) so it's really probably a single memory chip. That chip provides enough memory for 64 pages of text. To get the text to a “real” computer, a cable goes between the AlphaSmart keyboard and the keyboard port on your real computer. Upload the file from the AlphaSmart and edit on your big computer.

Since the AlphaSmart 2000 has no moving parts, no operating system, and no application beyond text processing, the boot time is about three seconds. You can start typing on this little keyboard quicker than you can pick up a pen and position a piece of paper.

I expect memory to get cheaper and faster to the point the entire MacBook operating system will be on a chip, and another few chips will provide 500GBs of storage space. This future MacBook may not run on three AA batteries like the AlphaSmart keyboard, but it will boot fast and get to work quickly.