An improved portable storage device is disclosed having an interface, a controller in communication with this interface, a memory in communication with the controller, and a light-emitting-diode assembly in communication with the controller. The light-emitting-diode assembly has a first and a second light-emitting-diode element, the first and second light-emitting-diode elements emitting a first and a second color of light, respectively. The first light-emitting-diode element and said second light-emitting-diode element each independently controlled by the controller via pulse-width-modulation, to produce a third color which appears to be in between the first and second colors in wavelength, this third color indicative of the percent completion of an I/O task or the usage of the memory.