Like humanity's original nomads, today's denizens of the open road must carry everything they need to make up a digital office into your shoulder bag or backpack.

And that's exactly what I did. I tracked down a selection of input devices, output devices and peripherals that can fit into a typical computer bag alongside a ten-inch netbook or even a reasonably-sized (say, a 14.1-inch) laptop.

Each device can run on its own power or use whatever it can draw from a USB port. And just in case your trusty laptop bag starts to pop its seams under the load, I also found some bags with the capacity to handle the strain.

Input devices

It is a truth universally acknowledged that mice are better than trackpads, and that's doubly true of the knuckle-crunching contraptions on today's netbooks. Enter the retractable-cord mouse, which uses a flat cord that winds up into a spring-loaded reel. For example, the $26 Targus Laptop Optical Mouse and the $15 Targus Ultra Mini Retractable Optical Mouse are USB 1.1 wheelie mice that look and work the same; the Ultra Mini i just much smaller - only a whisker over 3 inches long.

Only slightly less widely accepted is the truth that the cord on a regular mouse can get in the way, especially when you're trying to maneuver on a coffee shop table. Consider Logitech's V320 Cordless Optical Mouse ($39) package, which uses a tiny USB transmitter on a 2.4Ghz network to communicate with the nicely designed cordless mouse. The transmitter tucks into the mouse when not in use, a process that turns the mouse's power off.

Logitech wireless mouse

An even more energy efficient approach comes from the Logitech's $49 V550 Nano, which clips onto your notebook for easy carriage - and which turns off whenever it's clipped on. The rechargeable Lithium Ion batteries can, Logitech claims, go for six months or more without a charge.

LaCie Core4

If your work on the road involves entering a lot of numbers, you'll miss the numeric keypad on a proper keyboard. But you don't need to miss it: The Targus Numeric Keypad ($29.95) is a USB keypad complete with NumLock and an enlarged Enter key for your data entry pleasure. And it doesn't even take up a USB port to do it: It doubles as a two-port mini-hub.

Of course, not everyone who needs to bump up their USB port count also needs a numeric keypad. That's why there are hubs aplenty to fit a road warrior's pockets. One of the most elegant offerings I've seen is the matchbox-sized LaCie Core4, from the industrial design legend Sam Hecht.

This is a cheap $10 device with three empty USB ports and a built-in miniB cable. The miniB cable has become standard for many digital cameras, Razr phones, TomTom GPSes and a welter of other peripherals; having it built in is very convenient.