Ever been on a unknown computer, in an internet cafe, or a stranger's house and wanted to access websites which need passwords, which you either have forgotten, or don't want to risk giving them away to a key logger? Or simply want to surf without the host computer keeping track of everywhere you have visited?
Then portable applications are for you.
Instead of lugging around a whole laptop, with all issues of power, weight and security, you could just take a small USB stick. Or even use your iPod.
That specially-prepared stick contains your applications, together with relevant account names and passwords, your address book and as many files as you need. If you ever need to access your online bank account while on the move, they can (sometimes) be used to log in without the need to key in passwords, to defeat key loggers. You can also use an email client, without having to type your webmail passwords.
The systems are designed to leave a zero, or near-zero footprint on the host computer. This is supposed to minimise the security risks associated with unknown computers — and computer administrators.
Finally, all data on the stick can be encrypted, so that if it gets lost, the finder gets only a stick, but cannot gain access to your data.
Sounds attractive? Read on!
There are two main systems for this. U3 is the Internet Explorer of the portable apps world. It is a proprietary standard, and it aims to make money for its originators - SanDisk and M-Systems. It is available only for Windows operating systems.
Portable apps (PA) is the Firefox to Sandisk's IE. Portable apps is open source. It is available for Windows and Linux, and everything is free.
Other systems are available, but these tend to be less popular and less widely supported. V3 by Prayaya, MojoPac by RingCube and the range of Ceedo products are all aimed exclusively at Windows. Launchy was originally written for GNU/Linux but has been ported to Windows.
The only Mac system I can find, and that was thanks to XWiz, is http://www.freesmug.org/portableapps/. This is also based on open source software, but for OS X.
All of them work in much the same way. The initial preparation of the stick creates a partition which contains the system software. Under U3, when you plug in the memory stick, it acts like a virtual CD and auto-loads. Under PA you have to launch a program on the stick.
In each case, these actions lead to a menu panel appearing, usually in the lower right corner. This panel contains links to your applications (Mail client, web browser, FTP software, messaging clients and so on), each of which contains the relevant preferences, such as your account names and passwords. The panel also contains options for managing the programs — removing them, adjusting the order and adding more.
All these are stored on the memory stick, and occupy some of the space. However, they have been stripped down to minimise the storage requirement, and also are saved in special formats. This means they are available for download, but only from special sites, but theses sites are easy to find, because links are built into the control software.
The stick also holds your documents and projects, so that you can use your favourite apps, set up to your personal preferences to work on your favourite projects, even without carrying a laptop around.
Unfortunately, with windows applications, where a lot of program-specific data is stored in the registry, it's not possible to store all the passwords, though there are password managers available, and it is also possible to store them as text in a document, so that they can be cut-pasted into the entry boxes. This avoids entering sensitive informtion as keystrokes.
I've had a 1GB U3 stick for three or four years and recently bought a new one with 4GB capacity, as the original stick was getting a bit full. System software, Open Office, Thunderbird, Firefox, Skype and some security software occupied around 600MB, leaving just 300 or so for emails, documents and what have you.
With a 4GB stick, I now have ten times as much storage and it appears to be plenty.
The main drawback of U3 is that it needs to be factory installed, as there is a specific piece of hardware needed to allow the U3 system to operate. It's possible to remove the U3 software from a stick and then re-install it, because the hardware is present on the stick. Also, some drives have the U3 hardware installed, without advertising the fact. U3 has a wide range of software available, but most of it needs to be paid for. However, Thunderbird, Open Office, Filezilla and Firefox are all available for free.
I recently discovered Portable Apps, which is the open source equivalent of U3, and it also works, but has a much wider range of open source applications available than does U3. Also, PA can be installed on any USB stick, or on an iPod.
Portable Apps is available for Linux as well as for Windows, although the system software is obviously different for each platform. I guess you could have the software for Linux and the software for Windows on the same stick, but it will take up a twice the space.
Portable Apps has a much wider range of free software available, including GIMP, Audacity, VLC media player and a wide range of games.
Sources, further information