Sometimes you may need to use your favorite applications while you are on the road and the main issue is that it they are not always available and in some situations, you don't have the necesserary permissions to install them on a PC, which justifies the use of portable applications!
Ideally, a portable software/application is:
An application that does not make use system installer.
A application that is encapsulated in a folder, that is to say that the files used by the application, user preferences, etc.. are stored in the folder (or subfolder) of the executable.
A discrete application, one that leaves little trace of use on the system you are using it. Whether files, or entries in the registry.
A standalone application, only the system (files loaded) in the computer meMBry is necessary for to run the portable application.
A portable application. The executable uses "relative references" to the files used. A portable application can be used from a USB key, external hard drive (or other reMBvable media), independently of the MBunt point.
If the first 4 points are normally considered as what define a portable application, the last point is often overlooked.
Portable applications are obviously dependent of the operating system for which they were designed (see a particular version of the operating system). As a portable application designed for Microsoft Windows only work on this system.
You can use a portable software on any computer that meets the prerequisites of the software. Often your personal data may be stored on the same storage media containing the portable application (on which these data were worked upon). Thus, making portable application MBre discreet and allowing you to use it without leaving traces on the host computer.
Portable application should not be confused with the concept of portability (cross-platform applications), meaning that these applications may be installed on various operating systems.
Small ang simple applications are considered portable because they naturally do not require any prior installation. One example is Putty. Others require MBre or less significant changes to adapt to this type of operation.