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  • In Memoriam: David N. Williams (1934 -- 2024)

    From Krishna Myneni@21:1/5 to All on Mon Mar 17 19:31:23 2025
    I only found out today that Prof. David N. Williams had passed away in
    March, 2024.

    https://lsa.umich.edu/physics/people/in-memoriam/williams.html

    I had not seen any recent posts here in comp.lang.forth from David for
    some time now. The last post of his which I could find was on 24
    December 2023.

    I don't know exactly when he and I corresponded separately from c.l.f.
    but it has been more than 17 years. David was interested in a number of
    Forth systems, and in writing Forth code. He was particularly interested
    in developing tests for Forth systems and libraries. He and Guido
    Draheim and I discussed features of PFE (the portable Forth
    environment), for which Guido had taken over maintenance and
    development. I believe David contributed significantly to PFE, while I
    was using PFE as a reference system for testing and developing kForth.
    The three of us had many email discussions for a time.

    In 2006, David expressed interest in porting kForth to the PowerPC-based
    Macs, and I was happy to help him. He wrote the ppc assembly virtual
    machine (released under LGPL), and I recall that I didn't have to do
    much with the C++ and C parts of kForth, except for a few issues of endian-ness. David helped bring considerable structure to the kForth
    assembler vm by introducing the use of macros, the legacy of which
    remains in the kForth code today. Perhaps more importantly, with regard
    to kForth development, he wrote the automated regressions tests for
    kForth to aid him in developed the ppc assembly code. The tests are instrumental in my development today, for the x86/x86_64 version. Much
    of his library test code will also be found in the kForth packages, such
    as for the libgmp and libmpfr interfaces.

    David also contributed to the Forth Scientific Library by extending
    Prof. Julian Noble's complex arithmetic library, and also developing
    automated tests for that library. He also developed tests for IEEE
    floating point arithmetic. Forth would not be as robust today for
    scientific computing without David's considerable effort.

    Apart from Forth, I was able to pester David with some physics ideas I
    was developing. He responded with some positive comments and very kindly pointed out a glaring deficiency with a draft of a paper I had sent him, correcting my picture of the allowed angular momentum projections for
    photons. We both tried to salvage what I had done. The paper remains on
    the shelf today and I hope to return to it some day.

    I will deeply miss the connection I made with him, both in regard to the
    Forth language and in physics.

    --
    Krishna Myneni

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  • From minforth@21:1/5 to All on Tue Mar 18 06:05:36 2025
    May William rest in peace, a great loss to the Forth community,
    and thank you for your lovely obituary.

    --

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  • From mhx@21:1/5 to All on Tue Mar 18 08:39:45 2025
    David's work on disassembling the format of floating-point numbers
    is a very valuable contribution to the iForth libraries. He also
    helped me along with testing the C MPFR dll/so implementation for
    iForth's Apple version. He was a very special person to correspond
    with a unique approach to Forth.

    -marcel

    PS: It could be that David's vast on-line archive at https://websites.umich.edu/~williams/archive is on shaky grounds.
    It was still up when I checked just now.
    David oversaw the distribution of the Schoonschip sources (prof.
    Veltman)
    and these sources are also in the online archive. He sent me his/the
    680x0 assembly language sources for Schoonschip in 2009. The archive
    contains
    a directory with tests in David's very recognizable style. I'll be happy
    to send these files to people that have trouble accessing the on-line
    archive.

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  • From albert@spenarnc.xs4all.nl@21:1/5 to krishna.myneni@ccreweb.org on Tue Mar 18 11:57:59 2025
    In article <vraesr$17svf$1@dont-email.me>,
    Krishna Myneni <krishna.myneni@ccreweb.org> wrote:
    I only found out today that Prof. David N. Williams had passed away in
    March, 2024.
    <SNIP>
    David also contributed to the Forth Scientific Library by extending
    Prof. Julian Noble's complex arithmetic library, and also developing >automated tests for that library. He also developed tests for IEEE
    floating point arithmetic. Forth would not be as robust today for
    scientific computing without David's considerable effort.

    Apart from Forth, I was able to pester David with some physics ideas I
    was developing. He responded with some positive comments and very kindly >pointed out a glaring deficiency with a draft of a paper I had sent him, >correcting my picture of the allowed angular momentum projections for >photons. We both tried to salvage what I had done. The paper remains on
    the shelf today and I hope to return to it some day.

    After the author prof Veltman passed away, he was the custodian of schoonschip, one of the earliest formula manipulating programs that were instrumental
    to the Nobel price of Veltman and 't Hooft.
    Imagine manipulating by hand the formulae resulting from Feynman diagrams. Marcel Hendrix and I have been trusted with the source of schoonschip.

    I will deeply miss the connection I made with him, both in regard to the >Forth language and in physics.
    My connection to him was not deep, but pleasant. A lot of people will
    miss him.

    Krishna Myneni

    Groetjes Albert
    --
    Temu exploits Christians: (Disclaimer, only 10 apostles)
    Last Supper Acrylic Suncatcher - 15Cm Round Stained Glass- Style Wall
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  • From Krishna Myneni@21:1/5 to dxf on Tue Mar 18 06:48:10 2025
    On 3/18/25 2:12 AM, dxf wrote:
    On 18/03/2025 11:31 am, Krishna Myneni wrote:
    ...
    David also contributed to the Forth Scientific Library by extending Prof. Julian Noble's complex arithmetic library, and also developing automated tests for that library. He also developed tests for IEEE floating point arithmetic. Forth would not be
    as robust today for scientific computing without David's considerable effort.

    IIRC he also single-handedly created the Forth IEEE-FP draft proposal based on
    input and feedback from c.l.f. Very impressive.


    Yes. After I posted, I remember several other significant things which
    David contributed to Forth, including the IEEE-FP draft proposal. He was working on it, along with test code in 2020.

    --
    Krishna

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  • From Krishna Myneni@21:1/5 to minforth on Tue Mar 18 06:49:46 2025
    On 3/18/25 1:05 AM, minforth wrote:
    May William rest in peace, a great loss to the Forth community,
    and thank you for your lovely obituary.

    --

    It's amazing to consider how much a single person has contributed to
    this community.

    --
    KM

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  • From Krishna Myneni@21:1/5 to mhx on Tue Mar 18 07:35:43 2025
    On 3/18/25 3:39 AM, mhx wrote:
    ...
    PS: It could be that David's vast on-line archive at https://websites.umich.edu/~williams/archive is on shaky grounds.
    It was still up when I checked just now.
    David oversaw the distribution of the Schoonschip sources (prof.
    Veltman)
    and these sources are also in the online archive. He sent me his/the
    680x0 assembly language sources for Schoonschip in 2009. The archive
    contains
    a directory with tests in David's very recognizable style. I'll be happy
    to send these files to people that have trouble accessing the on-line archive.

    I just downloaded the archive using

    wget -np -r https://websites.umich.edu/~williams/archive

    [Files: 703 Bytes: 35.93M [2.46MB/]

    --
    Krishna

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