Abstract: A method and system for use primarily, but not exclusively, in digital communications switching systems are disclosed, in which the size of traffic-sensitive (temporary) size-alterable memory files is automatically increased when file congestion occurs. Preferably, the logical size of the files is increased, which can be accomplished much faster than by conventional approaches, because there is no need to make physical memory store reallocations. Additionally, an operator and/or an application program can dynamically control the utilization of traffic-insensitive (permanent) size-alterable files.