Files expand and contract within themselves, because new records coming tend to represent the distribution of surnamed present in the area, and inactive records tend to be the same.
Files expand almost entirely based upon customer decisions and cannot be controlled.
Files are similar to Subject Files
Files expand with the addition of higher numbers, so expansion will always take place at one end of the file, while older, inactive records tend to be removed from the other end of the file.
Files expand uniformly, because new records are filed into 100 Terminals.
The workload in Alphabetical Files and Terminal Digit Files tends to be evenly spread throughout the system, even when the newest files are added.
The workload in straight Numeric Files tends to be concentrated at one end of the files, where the newest records are filed.
Terminal Digit was developed in order to give a Numeric Filing sequence the same properties found in Alphabetical Files, with regard to work load and expansions.