Sort in memory constrained environments is interesting from a historical perspective. Mainframes did have small memory compared to data at one time. The solutio

Sort in memory constrained environments is interesting from a historical perspective. Mainframes did have small memory compared to data at one time. The solution was “disk sort” a process to sort files in chunks into sub files and merge the sub files into the final sorted file. Sorting is a pretty big deal in batch systems even today.