Abstract: Disclosed herein is a method of writing data into, reading data out of, and/or removing data from a state changeable chalcogen medium. According to the disclosed invention projected beam energy is applied to the medium to change a discrete portion of the medium from a solid state of first relative order to a solid state of second relative order through an intermediate state of relatively high mobility. The invention disclosed herein further contemplates applying projected beam energy to the medium to change the discrete portion of the medium from the state of second relative order through a relatively high mobility intermediate state back to the state of first relative order. In this way the written carrier to noise ratio is relatively high, the erased carrier to noise ratio is relatively low, and the carrier to noise ratios and contrast ratio are maintained relatively constant substantially independent of the cycle numbers.