List reasons why each of the following systems may require ‘maintenance’ in the future and, 61 as such, whether they might be classified as being E-type or S-type. Identify the relevant form of...

List reasons why each of the following systems may require ‘maintenance’ in the future and, 61 as such, whether they might be classified as being E-type or S-type. Identify the relevant form of maintenance likely to be employed for each case: (a) a spell-checking program used with a word processor that supports multiple languages; (b) a program used to list the contents of a directory (folder) used in an operating system; (c) a system used to display information about the position of aircraft in an air traffic control system that is used to manage the airspace for a number of busy airports.