A Watch That Sinks Under Its Features By David Pogue 100 Seconds With Pogue: Galaxy Gear: The Times's David Pogue tests out Samsung's new smartwatch. 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 any time 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. The watch is huge, but it's beautifully disguised to hide its hugeness. You can buy it with a plastic wristband in different colors. You can't exchange the bands, though, because important elements are built into it: a micro-speakerphone in the clasp and a tiny camera lens in the band. The Gear looks and feels fine on your wrist. It's not waterproof, but Samsung says it can withstand little splashes. You charge its battery by clamping it into a tiny USB charger - every night. 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 - and choose a watch face for its Home screen. The watch's sole button, on the side, always opens this Home screen. You have a choice of various analog and digital displays. 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. Videos are tiny and short (15 seconds long); you can't shoot more than three in a row, and the watch holds only 15 of those. But let's not quibble - it's a watch. But if you thought it was creepy that Google Glass lets your conversation partner film you without your knowledge, you ain't worn nothing yet. 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. And vice versa. Just be sure to lose them within 25 feet of each other. That's the range of Bluetooth, which is what keeps the watch and device connected. 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. ALERT YOU OF INCOMING MESSAGES The watch lets you know who's calling, and even shows you text messages right on its 1.6-inch, 320 x 320-pixel touch screen. Goofily, though, it can tell you only that an e-mail message has arrived; it can't show you the text. It instead sends a signal to the device to display the message there, which sort of defeats the purpose. TAKE AND MAKE CALLS Believe it or not, you can make phone calls on the watch, via the phone in your pocket or wheelbarrow. It actually works, and it means you can be hands-free in all kinds of life situations besides the car. The sound quality is truly impressive, considering it's a watch. But there's not much volume. If there's a lot of background noise, you have to hold your wrist up to your head. You thought Bluetooth earpieces made people looked deranged, walking down the street talking to themselves? Don't look now. If Samsung has its way, everybody will walk around talking into their sleeves like Secret Service agents. CONTROL MUSIC PLAYBACK Your remote is now strapped to your wrist. E-mail: pogue@nytimes.com