source: trunk/third/ispell/Contributors @ 10334

Ispell has a long and convoluted history.  I have tried to track down
as much as possible about it and condense it below.

THE DEVELOPMENT OF SPELL-CHECKING AND THE FIRST ISPELL

The following background information on spelling checkers in general,
and ispell in particular, was provided to me by Les Earnest
(les@dec-lite.stanford.edu):

> The earliest spelling checker (of sorts) of which I am aware was in a
> program that attempted to automatically receive human-keyed Morse
> code, which can be ambiguous because of the variable timing between
> dots, dashes, intercharacter pauses, and interword pauses.  This
> program didn't use a full dictionary; instead, used a table of
> digraphs (two-letter sequences) that occur in English and barred
> improper letter sequences.  This program was written by someone at MIT
> Lincoln Lab around 1959 and, I think, ran on the TX-2 computer there.
> Unfortunately, I don't remember his name.  I might still have the
> paper he wrote in my files but it would take a major search to find it
> and I might not succeed.
>
> A program that I wrote in 1961 to read cursive writing contained a
> real spelling checker, using the 10,000 most common English words.
> It is reported in:
>   L. Earnest, "Machine Recognition of Cursive Writing," Information
>   Processing 62, (Proc. IFIP Congress 1962, Munich), North-Holland,
>   Amsterdam, 1963.
> and
>   N. Lindgren, ``Machine Recognition of Human Language, Part III -
>   Cursive Script Recognition'', IEEE Spectrum, May 1965.
>
> I brought that dictionary to Stanford and got a PhD student to write
> a spelling checker for text in Lisp running on our PDP-6 computer at
> the Stanford Artificial Intelligence Lab around 1967.
> Unfortunately, I do not remember which student it was; it could have
> been Gil Falk.  It was a rather simple program (certainly much
> simpler than the earlier cursive writing program) and I didn't think
> of it as a significant development at the time.
>
> [Later], I got another PhD student, Ralph Gorin, to do a better and
> faster spelling checker sometime in the early '70s, still using my
> old dictionary.  Ralph later wrote an article about it in CACM.  I
> believe that he later augmented the dictionary.

[note: Ralph has since informed me that he wrote no such article.  The
program was called SPELL and was written in 1971.  Ralph provided me
with a reference to "Computer Programs for Spelling Correction", by
James L. Peterson, Springer-Verlag, Berlin, 1980, No. 96 in the series
"Lecture Notes in Computer Science."  This book states that Ralph's
SPELL program, which was the direct ancestor of ispell, was the first
computer program written for checking the spelling of text documents.
The book is also a good source of references on spelling programs.]

> ...
>    
> [Ispell] was originally written in PDP-10 assembly language and ran
> under the WAITS operating system, which is similar to TOPS-10 but existed
> only on SAIL (a dual processor KA10/PDP-6 system).  It was and is called
> SPELL on that machine.  It later was modified to run under Tenex and
> TOPS-20.

[Ralph mentions that SPELL was also ported to MIT's ITS and TOPS-10.]
   
The Tenex version of ispell was later revised by W. E. Matson (1974),
and Bill Ackerman (1978).  Bill has provided the following information:

> I came across the SPELL program in 1978 on ITS.  It was a port from
> Stanford, and had the names Ralph Gorin (approximately 1971) and
> Wayne Matson (1974) associated with it.  I did 3 things to it:
>
>    Rewrote it as a native program for ITS, and, shortly thereafter,
>       TOPS-20.  (I never did anything for TOPS-10, and am not aware
>       that it ever ran on TOPS-10, though it may have.)
>
>    Replaced the heuristics for suffix removal, which I found unreliable
>       and unsatisfactory, with an algorithm that was driven by specific
>       suffix flags in the dictionary.  This way, the dictionary would have
>       complete control over what words were legal, and there would be no
>       spurious hits.
>
>    Apparently most importantly, though I had no idea at time, gave it
>       the name "ISPELL", for "ITS version of spell", since I didn't
>       consider myself authorized to throw away an existing program
>       and overwrite it with a new one under the same name.
>
> I have not followed the history of the program since then, and do not know
> if it still uses the "suffix flags" in its dictionary.  But if it does,
> I introduced them.  The Ispell algorithm that uses those flags to make
> accurate decisions about the legality of words was documented in great
> detail in James Peterson's Springer-Verlag book.  (He spent a semester
> at MIT while working on the book, and I provided him with a lot of
> information and documentation at that time.)
>
>                            Bill Ackerman
>                            wba@apollo.hp.com

Michael Adler adds:

> I did work on ispell in 1982.  Actually, I stole the ispell
> dictionary and suffix compression algorithm and wrote a spelling
> checker for CP/M in 8080 assembler that I very creatively called "SPELL."
> By sorting the dictionary alphabetically and using a difference encoding
> I managed to pack the entire dictionary that Bill was using in about
> 56Kb.  The CP/M program read a document, sorted all the words alphabetically
> and then checked them.  It then reread the document and compared words as
> it found them against the in memory, sorted and checked words.  SPELL was
> around in the public domain on CP/M.
>
> I was in high school at the time and talked to Bill only over email.
> We wound up in the same compiler group at Apollo in the late 80's by
> coincidence.

DEVELOPMENT OF THE C/UNIX VERSION OF ISPELL

In 1983, Pace Willisson (pace@prep.ai.mit.edu) wrote a C/Unix version
from scratch, based on the ispell documentation.

In 1987, Walt Buehring revised and enhanced ispell, and posted it to the
Usenet along with a dictionary.  In addition, Walt wrote the first version
of "ispell.el", the emacs interface.

Geoff Kuenning (geoff@ITcorp.com, that's me, and by the way I
pronounce it "Kenning"; the "u" is silent) picked up this version,
fixed some bugs, and added further enhancements, all of which made me
the de-facto ispell maintainer for the net.  I also put quite a bit of
work into improving the quality of the dictionaries.  In 1987 I began
work on the "munchlist" script, which I originally intended to be used
to add flags to personal dictionary entries.  At the same time I was
studying German, and wanted to use ispell to check the papers I was
writing for that class.  After thinking about it for some time, I
realized that the suffix flags could be table-driven, which would both
add flexibility and would get rid of certain difficult-to-find bugs.
In 1988 I rewrote major portions of the code to do this, resulting in
the first multi-lingual version.  Ole Bjoern Hessen (obh@ifi.uio.no)
in Norway alpha-tested this version and provided several important
enhancements.

Bob Devine (vianet!devine) provided two larger dictionaries (which
became the basis for english.1 and english.2) to me for inclusion
with subsequent releases.

Ashwin Ram (ram@cs.yale.edu) made substantial enhancements to Walt
Buehring's emacs interface, and provided them to me for inclusion
with an earlier release.

The emacs interface was then completely overhauled by Ken Stevens
(stevens@hplabs.hp.com), who also beta-tested the software and
without whom this posting would not have been possible.  If there's a
feature in the emacs interface that you like, you probably have Ken to
thank for it.  His efforts have been tireless for many years.

Martin Boyer made major contributions to the munchlist script,
including producing a version that runs under perl (see
languages/Where for instructions on how to get that version).
Philippe-Andre Prindeville provided xspell (a Motif-based X
interface), and Moritz Willers provided a NeXTStep interface.

DEVELOPMENT AND DEATH OF ISPELL 4.0

Meanwhile, and unbeknownst to me, Pace Willisson was working on his
own improvements to ispell.  He focused primarily on dictionary size
and startup time.  His solution was a dictionary compression algorithm
that detected and encoded frequent letter pairs.  This also reduced
the time needed to read it in.  Pace also changed some internal data
structures to improve startup time.  Pace and I eventually discovered
each other's efforts, and discussed re-merging our changes, but we
decided that there would be too much work involved.  This was partly
because I was close to a release and didn't want to delay it with an
extensive and error-prone merge.

In late 1992 (if my memory serves correctly), Richard Stallman
contacted me, asking for permission to distribute ispell as part of
the GNU suite.  I responded that he was welcome to distribute it, but
that I was not willing to place my software under the Gnu Public
License.  Through a misunderstanding, neither of us considered the
possibility of finding a compromise license that both could live with.
So Richard started a search for an alternate version, and found Pace
working right in his back yard.

I have been told that when FSF first learned of Pace's version, they
again considered using International Ispell instead because it was
both more popular and more capable, but this idea was rejected due to
the license misunderstanding.  Instead, FSF enhanced Pace's version
somewhat and called it ispell 4.0, apparently in the hopes that by
numbering the version higher, it would become the standard.

When ispell 4.0 was released, much confusion ensued.  Many ispell
users innocently "upgraded" to 4.0 and then screamed when they could
not find features to which they had grown accustomed.  Europeans in
general were angered by the apparent provincialism shown by the
"dropping" of international support.  I found myself inundated with
questions about a version I had never heard of or seen.

One of the earliest and most common suggestions was that FSF should
rename their version "gispell".  This had a lot of precedent, both in
the naming of other FSF utilities and in the then-recent change of the
suffix used by gzip from ".z" to ".gz".  Unfortunately, the FSF
refused to do this.  I may have inadvertently contributed to this
refusal with a Usenet posting in which I tried to clarify what had
happened, pointing out that the FSF version was more recently related
to Pace's than my own.  This may have been seen as an acknowledgment
that FSF should have the rights to the name "ispell," and that I
should rename my version.

A flame war arose, and I decided that the only way to solve the
problem was to rename my version to eliminate the confusion.  However,
at about the same time Richard Stallman and I began negotiating via
e-mail.  We itemized and clarified his objections to my license, and I
learned from a third party that FSF is willing to distribute software
that falls under the University of California license (also known as
the Berkeley license).  Richard and I agreed that if I changed my
license to be a paraphrase of the UC license, FSF would be willing to
distribute my version with no changes.  Since then, ispell 4.0 has
been dropped by FSF and has pretty well disappeared from the net,
leaving 3.1 as the version of choice for nearly everyone.

OTHER CONTRIBUTORS

Many other enhancements and bug fixes were provided by the numerous
people listed below.  Do not assume, because I omit mention of their
specific contributions, that these persons were any less instrumental
in creating the version of ispell that you see before you.  Every one
of them made a significant contribution, and it is only a lack of
space that prevents me from detailing these contributions.  This
version of ispell is truly a cooperative effort, and it would not
exist without the help of the generous souls listed above and below.

A full list of contributors, including those mentioned above, follows.  (I
think I have listed everyone, but if you contributed and aren't listed,
let me know and I'll correct it):

        Ivar Aavatsmark
        Per Abrahamsen
        Robert Abramovitz
        Bill Ackerman
        Michael Adler
        Rohit Aggarwal
        Jose Joao Almeida
        Jerry Anders
        Boris Aronov
        Yves Arrouye
        Jamshid Afshar
        Michael C. B. Ashley
        Bertil Askelid
        Eric Backus
        Isaac Balbin
        Neal Becker
        Tony Bennett
        R. Bernstein
        Jim Berry
        Peter A. Bigot
        E. Jay Berkenbilt
        Benno Blumenthal
        Uwe Bonnes
        Marc Boucher
        Martin Boyer
        Ethan Bradford
        David Brooks
        Nicolas Brouard
        Peter Bruells
        Ferd Brundick
        Jack Bryans
        Walt Buehring
        Richard Caley
        John D. Campbell
        Keith Cantrell
        John Capo
        Bill Carpenter
        Jesus Carretero
        Michael W. Chang
        Steven Chaplin
        Wei-Jou Chen
        Peter Chubb
        Stewart Clamen
        Henri Cohen
        Ken Cox
        Robert Crowe
        Damian Cugley
        Ian Dall
        Kevin Dalley
        David Dalton
        Neal Dalton
        Hugh Daniel
        Mark Davies
        Frederic Devernay
        Bob Devine
        Paul Dickson
        Casper H.S. Dik
        Detlev Droege
        Steve Dum
        Alexander Durner
        Jiri Dvorak
        Les Earnest
        John Eaton
        David Edelsohn
        Jeff Edmonds
        Eric Eide
        Orjan Ekeberg
        Kevin Ellwood
        Michael Ernst
        L. Van Eycken
        Rik Faith
        Ralf Fassel
        George Ferguson
        Jeff Finger
        Werner Fink
        John Fitch
        Peter Flatau
        Jeffrey Friedl
        Georg Gieseke
        Ralph. E. Gorin
        Amos A. Gouaux
        Andy Gruss
        Michael Gschwind
        Ron Guilmette
        Bhusan Gupta
        Michael A. Guravage
        Chris Hadley
        Mark Hanning-Lee
        John Heidemann
        Arne Helme
        Ole Bjoern Hessen
        Karl Heuer
        Juergen A. Holm
        Denis Howe
        Joe Huber
        Brian Hunt
        imt3b2!imtsft (true name unknown)
        Lester Ingber
        Nick Ing-Simmons
        Richard L. Jackson, Jr.
        Michal Jaegermann
        John Jendro
        Bob Jewett
        Trevor Jim
        Gary Johnson
        Gjalt de Jong
        Don Kark
        Dan Karron
        Brendan Kehoe
        Steve Kelem
        Vivek Khera
        Axel Kielhorn
        Masahiro Kitagawa
        Peter Knaggs
        Don Knuth
        Jim Knutson
        Heinz Knutzen
        Fred Korz
        Sebastian Kremer
        Geoff Kuenning
        Ralf Lammers
        Markus Lautenbacher
        Jack Lawler
        Cherie N. Lawrence
        Charles Levert
        Doug Lind
        Torbjoern Lindgren
        Michael N. Lipp
        Ernst Lippe
        Richard Lloyd
        John Lu
        Dean Luick
        Erik Luijten
        Ian MacPhedran
        Martin Maechler
        Ross Maloney
        Albrecht Melan
        Lee Melvin
        Evan Marcus
        Simon Marshall
        Dave Mason
        W. E. Matson
        Meinhard E. Mayer
        Rob McMahon
        Bob McQueer
        Dean Messing
        Chris Metcalf
        Jim Meyering
        Hal Miller
        N.O. Monaghan
        Chris Moore
        Bernd Mueller
        Ulrich Mueller
        Guido Muesch
        John Murdie
        Peter Mutsaers
        Erik Toubro Nielsen
        Gaute Nessan
        Keith Neufeld
        Paul Nevai
        David Neves
        Mike Ogush
        Thorstein Ohl
        Piet van Oostrum
        Joe Orost
        Pham Dinh-Tuan
        Gildas Perrot
        Francois Pinard
        Israel Pinkas
        Paul Placeway
        Mick Pont
        Jim Prescott
        Philippe-Andre Prindeville
        Gary Puckering
        Philippe Queinnec
        Ashwin Ram
        Bill Randle
        Christopher Rath
        Joachim Reinert
        Rob Riepel
        Marc Ries
        Loren J. Rittle
        Germic Robert
        Philippe Robert
        Doug Roberts
        Kevin Rodgers
        Santiago Rodriguez
        Hagen Ross
        Jonathan Ross
        Arie Rudich
        Jonathan Ryshpan
        Bruno Salvy
        Rich Salz
        Julio Sanchez
        Paul A. Sand
        Ken Scales
        Bart Schaefer
        Greg Schaffer
        Harald Schlangmann
        Joachim Schrod
        Vernon Schryver
        Martin Schulz
        Gregory Neil Shapiro
        Guy Shaw
        David Shepherd
        Tom Shott
        Joel Shprentz
        Duncan Sinclair
        Vivek P. Singhal
        Klaus Singvogel
        George M. Sipe
        David M. Smith
        Perry Smith
        Luis Soltero
        David Spuler
        Richard Stallman
        Kevin B. Stanton
        Kjartan Stefansson
        Ken Stevens
        Andreas Stolcke
        Thos Sumner
        Bob Sutterfield
        Stefan Taxhet
        Gruppe Thi
        Julian Thompson
        Thomas Tornblom
        Michael Toy
        Bill Triggs
        Goeran (G\366ran) Uddeborg
        Marc Ullman
        Koaunghi Un
        Arjan de Vet
        Andrew Vignaux
        Christoph Vogelsang
        Jochen Voss
        David Waitzman
        Peter Watkins
        Gray Watson
        Patrick Weemeeuw
        Edward Welbourne
        Petri Wessman
        Michael Wester
        Peter Whaite
        Jon L. White
        Johan Widen
        Fredrik Wilhelmsen
        Moritz Willers
        Pace Willisson
        Joerg Winckler
        Bill Wohler
        Michael J. Wolski
        James Woods
        Frank Wuebbeling
        Avishai Yacobi
        Ken Yap
        Benny Yih
        Peter Young
        Jamie Zawinski
        Christos S. Zoulas