Opie is a GUI (Graphical User Interface) for the Linux operating system (and might work on other OSes as well). It was originally designed for handheld computers (such as the Compaq/HP iPAQ and the Sharp Zaurus), but could probably function well in other environments requiring a light GUI, such as an old laptop, or an internet kiosk. It is based upon QT/Embedded from Trolltech, which is in turn a graphical environment designed for embedded applications, based upon the QT toolkit. Opie has been designed for devices with small screens, and a touchscreen input device (ie, only one mouse click, and no constant mouse position), as well as designed to fit in a relatively small amount of storage space (about 5 megabytes for the base libraries and the launcher).