THE LOGO LINEAGE by Wallace Feurzeig
Wallace Feurzeig is a division scientist in information sciences for Bolt
Beranek and Newman.
His favorite implementation of Logo is still Logo-S for minicomputers.
Logo was created in 1966 at Bolt Beranek and Newman, a
Cambridge research firm. Its intellectual roots are in artificial intelligence,
mathematical logic and developmental psychology. The first four years of Logo
research, development and teaching work was done at BBN.
During the early 1960s, BBN had become a major center of
computer science research and innovative applications. I joined the firm in
1962 to work with its newly available facilities in the Artificial Intelligence
Department, one of the earliest AI organizations. My colleagues were actively
engaged in some of the pioneering AI work in computer pattern recognition,
natural language understanding, theorem proving, LISP language development and
robot problem solving. Much of this work was done in collaboration with
distinguished researchers at M.I.T. such as Marvin Minsky and John McCarthy,
who were regular BBN consultants during the early 1960s. Other groups at BBN
were doing original work in cognitive science, instructional research and man-computer
communication. Some of the first work on knowledge representation (semantic
networks), question-answering, interactive graphics and computer-aided
instruction was actively underway. J. C. R. Licklider was the spiritual as well
as the scientific leader of much of this work, championing the cause of on-line
interaction during an era when almost all computation was being done via batch
processing.
Time for Interaction
My initial focus was on expanding the intellectual capabilities of existing
teaching systems. This led to the first "intelligent"
computer-assisted instruction (CAI) system, MENTOR, which employed production
rules to support problem-solving interactions in medical diagnosis and other
decision-making domains. In 1965 I organized the BBN Educational Technology
Department to further the development of computer methods for improving
learning and teaching, and the focus of our work then shifted to the
investigation of programming languages as educational environments. This shift
was partly due to two recent technological advances: the invention of computer
time sharing and the development of the first high-level
"conversational" programming language.
The idea of sharing a computer's cycles among several
autonomous users, working on-line simultaneously, had stirred the imagination
of programmers in Cambridge in 1963 and 1964. BBN and M.I.T. teams raced to be
first in realizing this concept, with BBN winning by days and holding the first
successful demonstration of computer time-sharing in 1964. Our initial system,
designed by Sheldon Boilen, supported five simultaneous users on a DEC PDP-1,
all sharing a single CRT screen for output. Seeing dynamic displays from
several distinct programs, simultaneously and asynchronously ("out of time
and tune"), was a breathtaking experience.
Time sharing made feasible the economic use of remote
distributed terminals and opened up the possibilities of interactive computer
use in schools. We had recently implemented TELCOMP, one of the new breed of
high-level interactive programming languages. TELCOMP was a dialect of JOSS,
the first "conversational" (i.e., interpretive) language, developed
in 1962-63 by Cliff Shaw of the Rand Corporation; its syntax was similar to
that of BASIC, which had not yet appeared. Like BASIC, TELCOMP was a
FORTRAN-derived language originally designed for numerical computational
applications. Shortly after TELCOMP was created, we decided to introduce it to
children as a tool for teaching mathematics and in 1965-66, under U.S. Office of
Education support, explored its use as an auxiliary resource in eight
elementary and secondary schools served by the BBN time-sharing system.
Students were introduced to TELCOMP and then worked on standard arithmetic,
algebra, and trigonometry problems by writing TELCOMP programs. The project
strongly confirmed our expectation that the use of interactive computation with
a high-level interpretive language would be highly motivating to students.
My collaborators
in this research were Daniel Bobrow,
Richard Grant and Cynthia Solomon from BBN
and consultant Seymour Papert,
who had recently arrived at M.I.T. from Jean
Piaget's Institute in Geneva. The idea of a programming language expressly
designed for children arose directly from this project. We realized that most
existing languages were designed for doing computation and that they generally
lacked facilities for nonnumeric symbolic manipulation. Current languages were
inappropriate for education in other respects as well: they often employed
extensive type declarations that got in the way of students' expressive
impetus; they had serious deficiencies in control structures; their programs
lacked procedural constructs; most had no facilities for dynamic definition and
execution; few had well-developed and articulate debugging, diagnostic and
editing facilities, so essential for educational applications.
http://www.ordiecole.com/logo/logo_plcftm.jpg :
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Educational Expression
The need for a new language designed for and dedicated to education was
evident. The basic requirements for the language were:
1) Third-graders should be able to use it for simple tasks
with very little preparation.
2) Its structure should embody mathematically important
concepts with minimal interference from programming conventions.
3) It should permit the expression of mathematically rich
nonnumerical as well as numerical algorithms. Examples of nonnumerical problems
include translating English into pig Latin; making and breaking "secret
codes"; word games such as testing whether a word is symmetric (a
palindrome), finding words within words, writing words backwards;
question-answering and guessing games (such as "twenty questions" and
"buzz"). Our strategy was to introduce mathematical ideas through
experience with these familiar and meaningful problems and projects.
Incredibly, the best model for the new language (which was
to be as simple as possible) turned out to be LISP, the lingua franca of
artificial intelligence, often regarded (by non-LISP users) as one of the most
difficult and formidable of languages. Of course, the syntax of Logo is much
more familiar and accessible than that of LISP Essentially, though, Logo is
LISP and is thus both an easy and a powerful language. The power is not evident
in most existing microcomputer implementations, mainly because of their small
memory and restricted performance.
The initial design of Logo came about through extensive
discussions in 1966 between Seymour Papert,
Dan Bobrow and myself. Papert
developed the overall functional specifications for the new language, and
Bobrow made extensive contributions to the design and did the first
implementation. Subsequently, Richard Grant made substantial additions and
modifications to the design and implementation, assisted by Cynthia Solomon,
Frank Frazier and Paul Wexelblat. I gave Logo its name.
This first version of Logo was pilot-tested in the summer of
1967 with fifth- and sixth-grade math students at the Hanscom Field School in
Lincoln, Massachusetts, under support of the U.S. Office of Naval Research. In
1967-68 we designed a new and greatly extended version, which was implemented
on our DEC PDP-1 computer system by Charles R. Morgan. Michael Levin, one of
the original implementors of LISP, contributed to the design. From September
1968 through November 1969, the National Science Foundation supported us in the
first intensive program of experimental teaching of Logo-based mathematics in
elementary and secondary classrooms. The teaching experiments demonstrated in
principle that Logo can be used to provide a natural conceptual framework for
the teaching of mathematics in an intellectually, psychologically and pedagogically
sound way.
In 1970 Seymour Papert founded the Logo Laboratory at M.I.T.
Logo-based turtles, erroneously thought by many to be essential to the Logo
teaching enterprise, were introduced around 1971. Several hardware
implementations and teaching experiments followed during the decade of 1970s at
M.I.T., BBN and elsewhere.
Then came microcomputers. Their wide availability and
affordability catapulted Logo into becoming one of the world's most widely used
languages. At this point in its history, future development of exemplary
teaching ideas and materials is crucial to support the needs of users. Our work
on Logo development is continuing and continues to be compelling. Logo is an
idea whose time is now.
