provide an easy way of finding groups of related files

are only used when printing the contents of files

can be used when writing a file

allow several files to be read simultaneously

nine

six

five

two

the number of records added or deleted from a file composed to the original number of records in that file

efficiency with which non-sequential files are processed

the extent where the records of the file are contiguous and in proximity to others

percentage of records that has changed in a given time period.

two

four

five

six

random files

contiguous sequential file

indexed sequential file

all of these