What is an “end-of-reel” indicator mentioned in some of the data format descriptions?
An end-of-reel indicator was used as a way to indicate the end of a data file for those magnetic tapes that did not have a standard end-of-file indicator written. Various data processing programs tested for this end-of-reel indicator. Why include an end-of-reel indicator with the actual data rather than rely on a standard end-of-file indicator on tape? Well, during some data acquisition and processing methods, end-of-file indicators did not get written to the magnetic tapes. These days, the possibility of having a tape without a proper end-of-file indicator would seem unbelievable to the average computer users. But, for a moment, consider the circumstances under which these older tapes were created. These tapes were created by early data acquisition programs that required more user attention than the state-of-art acquisition systems currently being utilized. These early acquisition programs and hardware systems required an operator to manually instruct the computer system to write a st
