uses more tapes
should be done each month
saves only files that have recently changed
saves all files
single level directory
two level directory
tree structure directory
none of these
is needed by every installation
is never needed
varies in degree between installations
requires off-site computer for immediate use
text files
executable binary flies
both 1) text files and 2) executable binary flies
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