Alchemy OS is a MIDlet which creates an operating environment inside a mobile phone. Although it is not an operating system in the full sense, it provides a rich platform to develop, compile, and run applications directly in the phone.
PrefixDB is a mobile database of callsign prefixes in use by amateur radio. This database is helpful for the radio amateur while on the run. It is especially helpful for portable operations like QRP or handhelds (Echolink, etc.).