FullSync
FullSync is a Java-based utility that allows you to synchronize and back up directories on Windows. Actually, FullSync is not a portable application, but it can come in handy if you need to keep the applications on your computer and a removable storage device in sync.
For example, if you use Portable Firefox and Thunderbird, you might want to keep bookmarks, settings, email, and other stuff on your mobile hard disk in sync with their siblings on your computer. To do this, you create a FullSync job that synchronizes data in your Firefox and Thunderbird user profile with the profile on the mobile hard disk.
Torpark
If you plan to access the Web from public computers or from work, security and privacy should be your primary concerns. While Firefox allows you to remove all the private data saved on the disk, it does nothing to secure the Internet connection itself.
For security and anonymity, you can use Torpark, a combination of Portable Firefox and Tor. Tor uses a distributed network of servers called onion routers to create a secure and anonymous connection to the Internet. Torpark comes with integrated and preconfigured Tor software -- just launch the application and it takes care of the rest.
Torpark is rather slow, however, so if you want to use an application that demands a low-latency connection, such as the OpenWengo VoIP application (which I'll talk about in a moment), then you would be better off using it with Portable Firefox.
KeePass and Password Safe
Want to keep passwords and login data on a USB key? KeePass allows you to store all your passwords in an encrypted database. The database itself can be encrypted using either Advanced Encryption Standard (AES) or the Twofish algorithms, which are virtually impossible to break. You can use KeePass to group and sort multiple passwords as well as add new password groups and subgroups.
If you don't need all the bells and whistles of KeePass, you might want to opt for PasswordSafe, a simple utility that allows you to store user names and passwords in an encrypted database. The clever bit is that when you select a record, Password Safe copies the password from it into the Clipboard (you can change this behavior in the program's settings). When you close Password Safe, it clears the Clipboard, so no passwords are left behind.
TrueCrypt
One of the most effective ways to keep your documents and sensitive data on a USB key secure is to store them in an encrypted area of the device. TrueCrypt allows you to do this.
To install TrueCrypt on your USB key or mobile hard disk, launch TrueCrypt on your computer and choose Tools -> Traveller Disk Setup. Once TrueCrypt is installed, you can create an encrypted volume based on either a file or a partition. A friendly wizard guides you through the process of creating an encrypted volume and provides explanations of TrueCrypt's features. Mount the volume using TrueCrypt, and you can work with it as with a conventional disk drive.
NeoMem
NeoMem is a nifty little free-form database application that allows you to store virtually any type of information, including passwords, serial numbers, links, contact lists, notes, and anything else you can think of.
NeoMem allows you to define different classes, such as hardware, password, or bank account. Each class has its own properties, including a set of fields. For example, the bank account class would include the bank name, account number, type, notes, and so forth. You add a new record by creating a new object that belongs to a certain class. In this way, you can keep different bits of information in the same database. More importantly, NeoMem allows you to encrypt the created databases -- an essential requirement for any application that takes care of your private data.
Rainlendar
Despite its tiny size, Rainlendar is a great calendar utility that offers many useful features, such as support for whole-day and recurring events, event categories, reminders, and to-do lists. Rainlendar is not a portable application per se, but it will happily run from a USB key. Download a compressed version of Rainlendar, unzip it, and move to the USB key. If you already have Rainlendar installed on your computer, and you want to keep both calendars in sync, you have two options. You can use FullSync to copy the events.ini, todo.ini, and rainlendar.ini files to the Rainlendar folder on the USB key, or you can run the Rainlendar server, and use it to sync calendars.
Openwengo
If you are looking for a portable VoIP application, Openwengo will get you covered. Openwengo is open source software based on open standards, and it's available in two editions: as a standalone application and as a Firefox extension. The latter can be easily installed on Portable Firefox. To place calls with Openwengo, you have to create an account and purchase call credits. Openwengo allows you to call landline phones at rates comparable to those of Skype.
Damn Small Linux
If you want to run a full-fledged Linux desktop from your USB key, look no further than Damn Small Linux (DSL). This slim Linux distribution fits on a 128MB USB key, and it contains all the applications you are likely to need on the move.
Better yet, Damn Small Linux is available with the QEMU emulator, which allows you to run DSL from within Windows. Download the file dsl-embedded.zip from one of Damn Small Linux's mirrors, unzip the file, and launch QEMU by double-clicking on the dsl-windows.bat file. Admittedly, running DSL using QEMU is a painfully slow affair, but it does allow you to run Linux without leaving Windows and rebooting the computer.
Miscellaneous applications
Of course, these applications are just a tiny fraction of the available open source portable software. You might want to consider these portable applications as well.
- TightVNC is a great VNC server and viewer package that allows you to access and control remote computers.
- LockNote is a simple notepad with built-in encryption.
- Portable Thunderbird is a portable version of Mozilla Thunderbird, a popular open source email client.
- nPOP is a good choice if Portable Thunderbird is overkill for your email needs.
- Explore2fs is a simple tool that allows you to access Linux ext2fs partitions.
- Wackget is a Windows-based version of wget. It can help you to manage downloads.
- VLC media player can play virtually any media format.
- XAMPP Lite lets you run a full-fledged Apache/MySQL/PHP server from your removable disk.
- Miranda IM is a lightweight IM client that supports IRC, ICQ, MSN, Yahoo, AIM, and Jabber.
- Notepad++ is a text editor that offers syntax highlighting, regular expressions, and drag-and-drop functionality. It offers a tabbed interface (which allows you to quickly switch between multiple documents), multi-view mode (useful for viewing two documents side-by-side), and text zoom.
Obviously, if you want to replace your laptop with a USB key on your next trip, you won't have difficulty filling it up with useful applications. The software described here is enough to cover most of your mobile computing needs. Just make sure that the place you are heading to has a computer you can use with your USB key.