Sandisk is taking advantage of the declining cost of NAND flash memory to offer replacement solid state drives (SSD) for notebook users, starting with a 32GB model. Previously, large capacity flash-based drives had been used primarily by the military, aerospace and telecom industries, which required reliability under difficult environmental conditions. However, NAND flash memory has made SSD a viable and economically attractive alternative to existing technologies in a wider variety of applications, including mobile PCs aimed at enterprise and consumer users.