Firstly ROM and RAM do not indicate volitility (the ability to retain the contents in the absence of power). Quite simply, ROM means read only memory, and RAM random access memory. Either type could be implements as volitile or non-volitile memory.
Nearly always, ROM is used is non-volatile applications. But non-volitale RAM is common, in the form of flash memory such as compact flash or any of the other non-volitile memory types commonly used for modern digital music and imaging devices.
Nowdays flash memory is often used to store the system bios of a machine, or its ROM as it is sometimes referred to. This allows the contents to be re-written via software easily, where more convential EEPROMs used in past years to store what we tend to refer to as ROM requiered an specialized EEPROM burner to alter the contents.
