Upward Compatibility:

Design strategies must be devised that permit the adaptation of
new hardware components without major system revisions.  While
it's difficult to foresee the changes that will undoubtedly occur
in the relevant, existing technologies, or to anticipate fully
the new technologies that might significantly enhance the utility
of information integration and processing systems, there already
are general operational standards that can serve as a platform
for the development of contemporary applications.  The adherence
to technological standards with large followings will ensure the
continued viability of a carefully conceived system.  Upward
compatability can be expected for such basics as the MS-DOS and
Unix operating systems, and for programming languages with a
large user base such as "Pascal" and "C".  

It can be expected, of course, that the rapid pace of change will
continue, especially in the realm of hardware development. 
System designers must endeavor to assemble hardware and software
configurations so that this dynamic technological environment is
not viewed as a constraint to application development, but
instead as an opportunity for future system enhancement and
expansion.

<cfile18>   Problems in Information Science
<cfile70>   Storage Media: Structure and Stability
<cfile72>   Rate of Change
<ffile19>   Cautions