In the beginning, computers were the size of buildings. To use one, you walked into it.
Over the decades, they grew small enough to sit on a desk, then to carry in a briefcase, then to keep in your pocket.
And now we're entering the age of computers so small we wear them like jewelry.
Just what kind of jewelry, however, has yet to be decided. Will we wear our computers on our foreheads, as with Google Glass? Or will we wear them on our wrists, as with the new Samsung Galaxy Gear smartwatch ($300)?
Samsung isn't the first company to put a computer on your wrist. There have been a bunch of crude early efforts: the Pebble, the Cookoo, the Metawatch, the Martian. But the world waits for an Apple or Google or Samsung to do a more coherent job of packing a lot of components into a minuscule space.
Apple's iWatch is only a rumor. But Samsung's Galaxy Gear watch is here now. It's ambitious, impressive, even amazing. But it won't be adorning the wrists of the masses anytime soon.
One big reason: It's really only half a computer. It requires the assistance of a compatible Samsung phone or tablet; without one, the watch is pretty much worthless. And right now, only two gadgets are compatible: the Galaxy Note 3 (an enormous phone with the footprint of a box of movie-theater Raisinets) or Samsung's new 10.1-inch Galaxy tablet.
By Thanksgiving, Samsung says, it hopes to make its popular Galaxy S4 phone compatible, too; after that, the older Note 2 and S3. But the Gear watch will never work with devices from rival companies; Samsung is trying to create an Apple-like ecosystem of Samsung gadgets that work smoothly — and exclusively -— together.
So what does the Gear do? A hodgepodge of random things. Some work well, and some not. For example:
Tell the time: On your compatible Samsung phone, you install an app called Gear Manager. It's the front end for the watch, like iTunes for an iPod. It's how you change the watch's settings and customize its features.
Take pictures and videos: These aren't what you'd call National Geographic quality. The photos are 1.9 megapixels and the watch holds only 50 of them.
Find your gadgets: If you've misplaced the phone or tablet the watch is paired with, the watch can make it chime to help you find it.
Auto-unlock your device: If you're wearing the watch, you don't have to enter your password to unlock the companion phone or tablet. Clever, smart and effortless.
Take and make calls: Believe it or not, you can make phone calls on the watch, via the phone in your pocket or wheelbarrow. The sound quality is truly impressive, considering it's a watch.
Samsung, sooner or later, will learn that it can't build a coherent device just by throwing features at it.
David Pogue is the New York Times' tech columnist. He can be reached at davidpogue.com or @Pogue on Twitter. See full columns at fresnobee.com/pogue.