Although there are several different types of card in common use, they
all work in much the same way. They contain chips of a type of computer
memory called Flash memory, a technology first developed by Toshiba in
the early 1980s. The main advantage with Flash memory is that it can
store data for very long periods without being connected to a power
supply (it is non-volatile). In fact modern memory cards can potentially
store data for as long as 10 years without degradation..