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32 & 16 YEARS AGO
APRIL 1978
INTERNATIONAL DATA (p. 6) “AFIPS has named a panel
of US experts to study foreign countries’ activities which
restrict the international exchange of information. The
panel is also expected to respond to the State Department’s
position paper, Protecting Privacy in International
Data Processing.”
SOFTWARE QUALITY (p. 10) “For computer software
systems, quality appears to be a characteristic that can
be neither built in with assurance at system creation
time nor retrofitted with certainty after a product is
in use. Apart from the issues of logistics (copying and
distributing software) there appears to be a continuing
need to demonstrate some minimum level of quality in
typical wide-use software systems. At the same time
this appears to be impossible to accomplish: the best
designed systems have had errors revealed many years
after introduction, and several programs that had been
publicly ‘proved correct’ contained outright mistakes!”
SOFTWARE REVALIDATION (p. 14) “The problems of revalidating
software following maintenance have received
little attention, yet typically 70 percent of the effort
expended on software occurs as program maintenance.
There are two reasons to perform maintenance on a
software system: to correct a problem or to modify the
capabilities of the system. Revalidation must verify the
corrected or new capability, and also verify that no other
capability of the system has been adversely affected
by the modification. Revalidation is facilitated by good
documentation and a system structure in which functions
are localized to well-defined modules.”
ERROR DETECTION (p. 25) “It is well known that one
cannot find all the errors in a program simply by testing
it for a set of input data. Nevertheless, program testing is
the most commonly used technique for error detection
in today’s software industry. Consequently, the problem
of finding a program test method with increased errordetection
capability has received considerable attention
in the field of software research.
“There appear to be two major approaches to this problem.
One is to find better criteria for test-case selection. The
other is to find a way to obtain additional information (i.e.,
information other than that provided by the output of the
program) that can be used to detect errors.”
PROGRAM TESTING (p. 41) “So, there is certainly no need
to apologize for applying ad hoc strategies in program
testing. A programmer who considers his problems well
and skillfully applies appropriate techniques—regardless
of where the techniques arise—will succeed.”
SYMBOLIC
PROGRAM
EXECUTION
(p. 51) “The
notion of
symbolically
executing a program
follows quite
naturally from normal
program execution. First assume
that there is a given programming language (say, Algol-
60) and the normal definition of program execution for
that language. One can extend that definition to provide
a symbolic execution in the same manner as one extends
arithmetic over numbers to symbolic algebraic operations
over symbols and numbers. The definition of the symbolic
execution is such that trivial cases involving no symbols
are equivalent to normal executions, and any information
learned in a symbolic execution applies to the corresponding
normal executions as well.”
COMPONENT PROGRESS (p. 64) “It is clear, looking back,
that progress in component performance, size, cost, and
reliability has been reflected in corresponding improvements
in systems. Looking forward then, an analysis of
coming developments in logic and memory components
appears to be one approach to forecasting future system
characteristics. Prediction at the system level, however,
is complicated by various options in machine organization,
such as parallel processing and pipelining, which
interact with component features to establish the performance
limits of the system.”
HEMISPHERICAL KEYBOARD (p. 99) “A new hemisphericalshaped
typing keyboard, called the Writehander, permits
typing all 128 characters of the ASCII code with
one hand.
“To use the keyboard, the typist places his four fingers
on four press-switches and his thumb on one of eight
press-switches. The four finger-switches operate as the
lower four bits of the 7-bit ASCII code, selecting one of
16 character groups which contain the desired character.
Each group contains eight letters, numerals, or symbols.
The thumb then presses one switch to select the desired
character from the group of eight. The shape and switch
locations have been designed so that the fingers naturally
locate themselves on the switches, according to the
designer, Sid Owen.”
PDFs of the articles and departments of the April issues of
Computer for 1978 and 1994 are available through the IEEE
Computer Society’s website: www.computer.org/computer.
10 COMPUTER
Published by the IEEE Computer Society 0018-9162/10/$26.00 © 2010 IEEE
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