This means that you must perform certain actions on the files in these directories before their demos can be run successfully. Be sure to read this file and perform the required actions before trying to run any demos in a leading underscore directory. The Rational extender version seems to work best in these environments. It only allows what flat wouldn't fit before, to now proceed at a infuriatingly slow pace. The following material provides information on using virtual memory with the two supplied DOS extenders.
Virtual memory makes use of a swap file.
The use of virtual memory is far less direct. The minimum or initial size of the swap file. The size by which the swap file grows. The swap file name. By default the file is in the root directory of the current drive.