Application portability always has been a huge issue in the IT world because it is such a powerful idea: Move your applications to any machine at any time and they just run. No recompiling, no missing Dynamic Link Libraries, no registry issues, no missing drives. Ahh, that's how life should be. Of course, that is hardly how it is.Life with Windows applications is (to recontextualize Forrest Gump's famous bon mot) "like a box of chocolates." The difference is the chocolates are super glued in the box, there are tens of thousands of them, some are enormous and can't be eaten without eating scores of other chocolates, some have huge spikes sticking out of them, and others, if you forcibly remove them, blow up the box. Violently. This means that truly portable Windows applications have been rare.A slight digression: Some years ago we wrote about something called mobile agent technology. This was a wonderful idea in an incredibly geeky "we have no idea what we'll use it for but isn't it virtually shiny" kind of way.The concept behind mobile agents was you could create a process that would propagate around the 'Net transporting data from one machine to another, making it possible to do things such as process data on a powerful machine and return the results. Well, that all came to naught. It was just too complex; a solution looking for a problem.Back to the real world - it turns out that the portable applications we really need are productivity applications: the ones we use every day.We need these applications and associated data to move with us from one machine to another. What has brought this to the fore is the explosion of passwords, calendars and task lists that we need to carry around all the time.For example, we use a product called RoboForm (covered in Gearhead last year - see The Internet cowboy's sidekick) to store all of our logon data. We just checked and we have entries under RoboForm for more than 400 Web sites! This shows the kind of problem we all face when we're out and about, because we conceivably might need any one of those logons at any time. (Yes, we are that important!)Then there is our contact list, our collection of software licenses, our bank account details, our bookmark lists, our task lists and so on - all potentially crucial to our continued business success while we are on the road.Launched at last year's Consumer Electronics Show, a new standard based on USB flash drives aims to make data and application portability easier and more reliable. The standard, co-developed by SanDisk and M-Systems, is called U3.The U3 standard defines an open platform that allows users to plug applications and data into any PC equipped with USB and running Windows 2000 or XP. Applications that aren't U3-specific that are to run directly off a U3 drive have to be tweaked, but applications designed and written for U3 drives should be among the easiest for users to install and set up.Applications designed for U3 store their executables and supporting files in a package on the U3 drive. When the application is executed, the package is loaded into the system-defined temporary subdirectory on the host computer.The code is run from this subdirectory; when the application is closed, all associated files in the temporary directory are removed (this is not guaranteed, however, so deep-erase if you're handling, say, nuclear secrets).Unlike standard Windows applications, U3 applications are not hard-wired to the directory structure or operating system components on the host computer, and they are independent of the Windows Registry.Next week we'll delve deeper into U3 technology. Until then, tell email@example.com your portability problems, and check out the Gibbs Out Loud episode on Gibbsblog.