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by Jason Snell & Dan Moren

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PowerBook Duo Photos by Stephen Hackett.

By Jason Snell

20 Macs for 2020: #19 – PowerBook Duo

Most of Apple’s early laptops were, like today’s MacBooks, complete Macs. The premise was: “Let’s engineer a Mac that’s like the one on your desk, but put it in a single package with screen, keyboard, pointing device, and battery.” My first laptop was a PowerBook 160 and it did everything my old Mac SE did (and much, much more).

The PowerBook Duo was different. It wasn’t trying to be the Mac on your desk. Introduced in 1992,1 it was the MacBook Air or one-port MacBook of its time—all compromise in a quest to be as thin and light as possible. If you wanted the absolutely smallest, lightest Mac laptop you could find, you got a PowerBook Duo and dealt with the weirdness.

Separated at birth? The PowerBook Duo was the MacBook Air of its day, prioritizing thinness and lightness over “required” features.

How small and how light? By today’s standards the PowerBook Duo was laughably large, but 1992 was a different time. My first PowerBook weighed seven pounds; the first PowerBook Duo weighed four. It was also 1.4 inches thick—more than an inch thinner than my PowerBook.

But it wasn’t a complete Mac. It had a shrunken-down keyboard and trackball, and only a single standard port. (Sound familiar, MacBook fans?) There was no support for floppy drives, external hard drives or monitors. For all of that stuff, you needed to connect it to a docking station.

Today we don’t flinch at the idea of a computer without a built-in floppy drive, but back in the mid-90s, floppies were the currency of the realm. Even six years later, people screamed bloody murder when the original iMac was released lacking a floppy drive. The Duo? Nope. (If you needed access to floppies, you’d need to buy an external disk drive.)

It also didn’t have a headphone jack! This one seems completely bananas now—I can’t imagine working on a laptop out in public without plugging in headphones. But back then, we didn’t really play music on our computers—this was the Walkman era—so Apple got away with shaving that port off.

The only standard port on the Duo, hiding behind a little door that you could rotate and turn into a foot to help angle the keyboard perfectly for carpal tunnel syndrome2, was a single Mac serial port. That wasn’t nothing, because you could use it to connect to a modem (if you didn’t pay for the optional internal modem) or a printer or even a very slow local-area network via LocalTalk. But, that was it.

And this is where the PowerBook Duo got…interesting. It remains the only Mac to be built with an Apple docking station in mind. Apple sold two of them, and third-party vendors filled in the gaps with all sorts of other contraptions, all connected via the Duo’s most important (and most nonstandard) port, the 156-pin Processor Direct Slot.

When I say “Mac docking station,” you probably can imagine what I’m talking about. When I was a full-time PowerBook and MacBook user, I used a bunch of third-party ones—you’d connect your monitor, speakers, hard drive, and other stuff to a plastic frame and then slide your laptop into it to make the connections and hopefully not ruin the ports on the back or sides.

And yes, the Duo had those kinds of docks. It was the original Dongletown. Apple’s Duo MiniDock clipped on the back and added a modem jack, audio-in and audio-out plugs, a SCSI port, two serial ports, video out, ADB for keyboards and mice, a floppy-disk port, and an AC adapter. (If that seemed like too much, there was also a Duo Floppy Adapter, that added a floppy-disk port and an ADB port.)

But docking stations like that are kind of boring. What you wanted to do, if you were John Sculley-era Apple, was to create a big, bold docking station that could transform that tiny PowerBook Duo into a full-fledged desktop Mac. You wanted to create the Duo Dock, the accessory that makes the PowerBook Duo more significant than it would be if it were just Apple’s first attempt to make a tiny laptop.

The Duo Dock (with Duo inside). The two-tone color scheme matched PowerBook and monitor alike.

Here’s what MacUser’s Russell Ito wrote in his launch story:

Let’s get one thing clear: This thing looks weird. We’re not talking technology or functionality, mind you, just aesthetics. From its two-tone finish (platinum on top, granite on the bottom—according to Apple, the top will match your monitor, and the bottom, your PowerBook), to its partially melted-looking lid, to its strange cylindrical feet sticking out the sides, this is easily the most visually “unusual” computer Apple has produced since the Lisa.

I prefer to think of the Duo Dock as a front-loading VCR that takes laptops instead of videocassettes3. Because that’s how it worked. You closed your Duo and inserted it into the tray of the Duo Dock, which would eventually click into place and pull itself snugly closed. In a decade when Apple never skimped on custom intercapped names for their products, the system that locked the Duo in place in the Duo Dock was called PowerLatch.

The Duo Dock packed in all the parts of a desktop Mac that weren’t present on the Duo. There was a floppy drive (not just a connector, like on the MiniDock), a hard-drive bay for a single 3.5-inch half-height drive, two NuBus slots—that’s right, you could install add-on cards that the computer could use when it was docked—space for additional video RAM (to drive larger monitors), and even a slot for a floating-point unit (FPU) chip. This was a dock that could actually expand your computer’s central processor and make it faster.

Patented PowerLatch™ technology.

That level of integration came at a cost: You basically needed to shut down your laptop to eject it from the Dock. If you pressed the eject button on the Dock—yes, there was an eject button—it would tell the Duo to shut down, and you’d be prompted to save your files. Once the laptop was off, the ejection process would start. (When you inserted a Duo in the Dock, it would automatically reconnect you to your file servers, which was nice.)

Still, the idea of the Duo Dock was kind of brilliant. I frequently hear the hosts of one of my favorite podcasts debate the merits of going full-time with a laptop versus having a separate laptop and desktop. The Duo tried to provide the best of both worlds, with a light laptop that could inherit the traits of a desktop Mac when it was sucked into its little plastic house.

The lifespan of the entire PowerBook Duo product line from introduction to discontinuation was less than five years. But it lives on in reruns of NewsRadio, Seinfeld, and quintessential mid-90s films like “The Net” (which was shot at Macworld Expo San Francisco) and “Hackers.”

This time period coincides with my first few years working at MacUser magazine. I had never seen a Duo in the wild before I started to work at MacUser, and even there, they were rare. In an era that stands among the worst in Apple’s history, the full-featured PowerBook was a hit, but not the Duo. It lived off in its own parallel universe, a niche within a niche.

The Duo line was discontinued in early 1997, before Steve Jobs got the chance to kill it himself. Though you could make the argument that Apple’s Thunderbolt Display was a MacBook docking station disguised as a display, we never really saw the Duo Dock’s like again.

I’ll be back next week with number 18.


  1. The same year as my PowerBook 160! I never for a second considered buying a Duo, which says something about me or it or both. 
  2. That’s what we called RSI back in the ’90s. 
  3. That’s what we called Netflix in the ’90s. 

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