A file is written or not written to a first storage medium (as opposed to a second storage medium) as a function of its distribution-priority file-name extension character or characters and an available capacity of the first storage medium. A system includes a manufacture in the form of a computer-readable storage medium tangibly encoded with software. The software includes an operating system that, when executed, selects a first storage medium or a second storage medium to which to write a target file as a function of distribution-priority file-name extension characters of a file name for the target file and of available capacity on the first storage medium.