Portable mode is a method of running a program that does not require installation. The main advantage is that you can put it on a USB flash drive and move it from one computer to another simply by plugging in the USB flash drive. All your settings and data are kept with the program.
Digital Fake Book can be run in portable mode by passing the location of a custom data folder to the program on launch via the command line. I have simplified this process by writing a small program that will handle this for you, and included everything required in a zip file.
To use Digital Fake Book Portable, just unzip the zip file to a location of your choice on your hard drive or a USB flash drive. There is no installer to run. Just make sure the location you unzip to is writable.
To run Digital Fake Book in portable mode, just run the DigitalFakeBookPortable.exe program. The data files will be kept in the dfb subfolder.
Although you can link audio files from anywhere, I recommended that you copy any audio files you want to use with Digital Fake Book Portable to the Audio subfolder under the dfb folder. That way, you can be sure Digital Fake Book will find them, even if you move it to a different computer.
It's important to keep the file and folder structure the same as it is in the zip, as the program expects to find the various files in particular locations in relation the the program file.
Digital Fake Book uses a custom font called Bitstream Vera which may not be available on the computer you are using, so you may want to download and install it. http://en.wikipedia.org/wiki/Bitstream_Vera If this font is not available on your computer, Windows will substitute the nearest it can find. This will usually be Courier New, which is a much wider font than Bitstream Vera.
The portable version is also useful if you want to run multiple versions with different configurations of song data. Just create several different portable folders and run the version with the data you want to use.