9 Apr
2022
9 Apr
'22
1:45 p.m.
Single Level Storage is an awesome concept and removes
so many ugly
hacks from algorithms that otherwise have to process data in files.
This was Vic Vyssotsky's signature contribution to Multics, though in typical
Vyssotsky fashion he never sought personal credit for it. Other awesome
Vyssotsky inventions:
BLODI (block diagram), the first data-flow language, for sample-data systems.
Parallel flow analysis (later reinvented and published by John Cocke). Vic
installed this in Fortran to produce diagnostics such as, "If the
third branch of IF
statement 15 is ever taken, then variable E will be used before being set".
Darwin, the original game of predation and self-reproduction among programs.
Corewars.org keeps a descendant version going 60 years later.
A minimum-spanning-tree algorithm quite different from the well-known methods
due to his colleagues Bob Prim and Joe Kruskal, again unpublished.
Not long ago on TUHS, Andrew Hume told how Vic found the same isolated bug in
dc by mathematically generating hard cases that Andrew stumbled on by accident,
As you may infer, Vic is one of my personal computing heroes.
Doug
9 Apr
9 Apr
3:09 p.m.
New subject: {TUHS] Interesting Commentary on Unix from Multicians
I worked for Vic at the Digital Cambridge Research Lab. Entirely awesome. Another Vic
story is how he got sent to visit the Pave Paws radar on Cape Cod because the locals were
worried that software errors in the phased array controls could zap the populace.
Vic talked to the radar people and found out that there was a hardware stop that prevented
beam angles below 3 degrees, so there was no need to worry about bugs.
Vic would always remember what the original problem was, rather than get lost in
irrelevant details.
-L
On Apr 9, 2022, at 7:48 AM, Douglas McIlroy
<douglas.mcilroy(a)dartmouth.edu> wrote:
Single Level Storage is an awesome concept and removes so many ugly
hacks from algorithms that otherwise have to process data in files.
This was Vic Vyssotsky's signature contribution to Multics, though in typical
Vyssotsky fashion he never sought personal credit for it. Other awesome
Vyssotsky inventions:
BLODI (block diagram), the first data-flow language, for sample-data systems.
Parallel flow analysis (later reinvented and published by John Cocke). Vic
installed this in Fortran to produce diagnostics such as, "If the
third branch of IF
statement 15 is ever taken, then variable E will be used before being set".
Darwin, the original game of predation and self-reproduction among programs.
Corewars.org keeps a descendant version going 60 years later.
A minimum-spanning-tree algorithm quite different from the well-known methods
due to his colleagues Bob Prim and Joe Kruskal, again unpublished.
Not long ago on TUHS, Andrew Hume told how Vic found the same isolated bug in
dc by mathematically generating hard cases that Andrew stumbled on by accident,
As you may infer, Vic is one of my personal computing heroes.
Doug 
8:25 p.m.
New subject: {TUHS] Interesting Commentary on Unix from Multicians
vic was my department head upon my arrival at
bell labs (june 1966). i went to my assigned office
and found vic, in combat boots, in a lotus position
on top of my filing cabinet. it is a vision that i will
never forget. he had just come to introduce himself.
On Sat, Apr 9, 2022 at 4:48 AM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
Single Level
Storage is an awesome concept and removes so many ugly
hacks from algorithms that otherwise have to process data in files.
This was Vic Vyssotsky's signature contribution to Multics, though in
typical
Vyssotsky fashion he never sought personal credit for it. Other awesome
Vyssotsky inventions:
BLODI (block diagram), the first data-flow language, for sample-data
systems.
Parallel flow analysis (later reinvented and published by John Cocke). Vic
installed this in Fortran to produce diagnostics such as, "If the
third branch of IF
statement 15 is ever taken, then variable E will be used before being set".
Darwin, the original game of predation and self-reproduction among
programs.
Corewars.org keeps a descendant version going 60 years later.
A minimum-spanning-tree algorithm quite different from the well-known
methods
due to his colleagues Bob Prim and Joe Kruskal, again unpublished.
Not long ago on TUHS, Andrew Hume told how Vic found the same isolated bug
in
dc by mathematically generating hard cases that Andrew stumbled on by
accident,
As you may infer, Vic is one of my personal computing heroes.
Doug
11 Apr
11 Apr
9:24 p.m.
New subject: {TUHS] Interesting Commentary on Unix from Multicians
On Sat, Apr 9, 2022 at 2:29 PM Ken Thompson <kenbob(a)gmail.com> wrote:
vic was my department head upon my arrival at
bell labs (june 1966). i went to my assigned office
and found vic, in combat boots, in a lotus position
on top of my filing cabinet. it is a vision that i will
never forget. he had just come to introduce himself.
This is a great story, though I confess that the thought of sitting like
that sounds rather uncomfortable.
I wonder if either or both of you, Ken, and Doug, could talk a little about
the Bell Labs withdrawal from Multics from your perspectives? What was that
like, and what was your relationship with the folks at MIT still at Project
MAC like afterwards? I gather it was friendly; was there any collaboration
there beyond casual correspondence?
- Dan C.
On Sat, Apr 9, 2022 at 4:48 AM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
Single
Level Storage is an awesome concept and removes so many ugly
hacks from algorithms that otherwise have to process data in files.
This was Vic Vyssotsky's signature contribution to Multics, though in
typical
Vyssotsky fashion he never sought personal credit for it. Other awesome
Vyssotsky inventions:
BLODI (block diagram), the first data-flow language, for sample-data
systems.
Parallel flow analysis (later reinvented and published by John Cocke).
Vic
installed this in Fortran to produce diagnostics such as, "If the
third branch of IF
statement 15 is ever taken, then variable E will be used before being
set".
Darwin, the original game of predation and self-reproduction among
programs.
Corewars.org keeps a descendant version going 60 years later.
A minimum-spanning-tree algorithm quite different from the well-known
methods
due to his colleagues Bob Prim and Joe Kruskal, again unpublished.
Not long ago on TUHS, Andrew Hume told how Vic found the same isolated
bug in
dc by mathematically generating hard cases that Andrew stumbled on by
accident,
As you may infer, Vic is one of my personal computing heroes.
Doug
28 Apr
28 Apr
11:05 p.m.
New subject: {TUHS] Interesting Commentary on Unix from Multicians
As the labs folks all probably know, Vic became the Executive Director of
division 91(two levels beyond department head).
This was after Research and Multics and, I think, Safeguard.
One of the early things he asked after quizzing various folks about what
was going on in the division was "Where is your source code control
system?".
The question fell to Rudd Canaday (then a department head under Vic).
And SCCS was thus born.
And who doesn't remember SP&E Aleph Null articles?
Alan
On Sat, Apr 9, 2022 at 7:47 AM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
Single Level
Storage is an awesome concept and removes so many ugly
hacks from algorithms that otherwise have to process data in files.
This was Vic Vyssotsky's signature contribution to Multics, though in
typical
Vyssotsky fashion he never sought personal credit for it. Other awesome
Vyssotsky inventions:
BLODI (block diagram), the first data-flow language, for sample-data
systems.
Parallel flow analysis (later reinvented and published by John Cocke). Vic
installed this in Fortran to produce diagnostics such as, "If the
third branch of IF
statement 15 is ever taken, then variable E will be used before being set".
Darwin, the original game of predation and self-reproduction among
programs.
Corewars.org keeps a descendant version going 60 years later.
A minimum-spanning-tree algorithm quite different from the well-known
methods
due to his colleagues Bob Prim and Joe Kruskal, again unpublished.
Not long ago on TUHS, Andrew Hume told how Vic found the same isolated bug
in
dc by mathematically generating hard cases that Andrew stumbled on by
accident,
As you may infer, Vic is one of my personal computing heroes.
Doug
30 Apr
30 Apr
12:45 p.m.
New subject: Aleph Null in Software Practice & Experience.
Hi,
Alan Glasser wrote:
> Darwin, the original game of predation and
self-reproduction among
> programs.
...
And who doesn't remember SP&E Aleph Null
articles?
Doug has made the letter from him, Bob Morris, and Vic Vyssotsky to
Software Practice & Experience which introduces Darwin available at
https://www.cs.dartmouth.edu/~doug/darwin.pdf. The letter is addressed
to C. A. Lang but accompanied by a note that Lang isn't א₀.
http://bit-player.org/2013/who-was-aleph-null wonders if א₀ and
side-kick Archimedes ‘might have been members of the Bell Labs gang that
was so lively and prolific in the late 60s and early 70s’ before
acknowledging the Darwin article rules it out. After a false start
suspecting Lang, foiled by Doug's PDF of the letter, it goes on to
finally identify א₀ as Brit Richard Parkins who explains how it came
about on his own page at http://www.zen224037.zen.co.uk/SPE.shtml.
Reading the front page of Parkins' site, http://www.zen224037.zen.co.uk,
I see he ‘learnt his craft’ by programming assembler when at Cambridge,
on the country's first PDP-7 which he was allowed to use by Lang and
Neil Wiseman. Unusually, it had a separate graphics processor driving a
1024²-pixel monochrome display.
Soon after, Parkins went on to build a graphics card for the Data
General Nova which drove a flat screen storage tube before Tektronix
released the 4010. The story is buried in
http://www.zen224037.zen.co.uk/History.shtml.
--
Cheers, Ralph.
5:42 p.m.
New subject: Aleph Null in Software Practice & Experience.
On Sat, Apr 30, 2022 at 3:53 AM Ralph Corderoy <ralph(a)inputplus.co.uk wrote:
accompanied by a note that Lang isn't א₀.
Note that on correct Unicode renderers this is being shown as null-aleph
instead of aleph-null. The reason for that is that you are using the
Hebrew letter, which is right-to-left and makes the neutral subscript zero
character rendered right-to-left as well. So instead of א U+05D0 HEBREW
LETTER ALEF, you need the identical-looking but left-to-right character ℵ
U+2113 ALEF SYMBOL, which will give you ℵ₀.
3:33 p.m.
New subject: Aleph Null in Software Practice & Experience.
The output of "unicode 5d0-5e7" (robpike.io/cmd/unicode has the
command) is fun.
05d0 א 05d1 ב 05d2 ג 05d3 ד
05d4 ה 05d5 ו 05d6 ז 05d7 ח
05d8 ט 05d9 י 05da ך 05db כ
05dc ל 05dd ם 05de מ 05df ן
05e0 נ 05e1 ס 05e2 ע 05e3 ף
05e4 פ 05e5 ץ 05e6 צ 05e7 ק
For comparison, here is "unicode 3d0-3e7". It will be fun to watch how
it's rendered.
03d0 ϐ 03d1 ϑ 03d2 ϒ 03d3 ϓ
03d4 ϔ 03d5 ϕ 03d6 ϖ 03d7 ϗ
03d8 Ϙ 03d9 ϙ 03da Ϛ 03db ϛ
03dc Ϝ 03dd ϝ 03de Ϟ 03df ϟ
03e0 Ϡ 03e1 ϡ 03e2 Ϣ 03e3 ϣ
03e4 Ϥ 03e5 ϥ 03e6 Ϧ 03e7 ϧ
-rob
2 May
2 May
11:55 a.m.
New subject: Aleph Null in Software Practice & Experience.
Hi Rob,
The output of "unicode 5d0-5e7"
(robpike.io/cmd/unicode has the
command) is fun.
05d0 א 05d1 ב 05d2 ג 05d3 ד
05d4 ה 05d5 ו 05d6 ז 05d7 ח
05d8 ט 05d9 י 05da ך 05db כ
05dc ל 05dd ם 05de מ 05df ן
05e0 נ 05e1 ס 05e2 ע 05e3 ף
05e4 פ 05e5 ץ 05e6 צ 05e7 ק
For comparison, here is "unicode 3d0-3e7". It will be fun to watch how
it's rendered.
03d0 ϐ 03d1 ϑ 03d2 ϒ 03d3 ϓ
03d4 ϔ 03d5 ϕ 03d6 ϖ 03d7 ϗ
03d8 Ϙ 03d9 ϙ 03da Ϛ 03db ϛ
03dc Ϝ 03dd ϝ 03de Ϟ 03df ϟ
03e0 Ϡ 03e1 ϡ 03e2 Ϣ 03e3 ϣ
03e4 Ϥ 03e5 ϥ 03e6 Ϧ 03e7 ϧ
In the terminal where I read and write email, they're all as if ‘0041 A’.
But save the email's text/plain to foo.txt and foo.html, add a little HTML
to foo.html, and the browser, here Firefox, presents the Hebrew in both as
05d0 05 אd1 05 בd2 05 גd3 ד
05d4 05 הd5 05 וd6 05 זd7 ח
05d8 05 טd9 05 יda 05 ךdb כ
05dc 05 לdd 05 םde 05 מdf ן
05e0 05 נe1 05 סe2 05 עe3 ף
05e4 05 פe5 05 ץe6 05 צe7 ק
due to the mix of Unicode's strong, weak, and neutral bi-directional
character types.
To see what I intend above needs a ‘broken’ renderer, like a terminal.
For those with more intelligent renderers, it's as if runes normally
drawn as
00c0 À 00c1 Á 00c2 Â 00c3 Ã
became
00c0 00 Àc1 00 Ác2 00 Âc3 Ã
Wrapping each of the Hebrew characters in the text and HTML files in
LRI...PDI,
LRI U+2066 Left-to-right isolate
PDI U+2069 Pop directional isolate
so the first row becomes
0030 0035 0064 0030 0020 2066 05d0 2069 0020
0030 0035 0064 0031 0020 2066 05d1 2069 0020
0030 0035 0064 0032 0020 2066 05d2 2069 0020
0030 0035 0064 0033 0020 2066 05d3 2069 000a
has Firefox display the tables as intended. Perhaps the unicode command
should do this to ensure correct display, especially if some terminals
ever start to improve?
I note that vim(1) here doesn't realise LRI and PDI are zero width
so the cursor position drifts past the end of the visible line.
ed(1) copes without a murmur.
--
Cheers, Ralph.
12:03 p.m.
New subject: Aleph Null in Software Practice & Experience.
Under option, maybe. I'm not a fan of putting invisible characters
into a program designed to translate numbers into cut-and-pasteable
text. Plus, as you said, it just makes other things break, although
perhaps they should be encouraged not to.
-rob
On Mon, May 2, 2022 at 7:56 PM Ralph Corderoy <ralph(a)inputplus.co.uk> wrote:
Hi Rob,
The output of "unicode 5d0-5e7"
(robpike.io/cmd/unicode has the
command) is fun.
05d0 א 05d1 ב 05d2 ג 05d3 ד
05d4 ה 05d5 ו 05d6 ז 05d7 ח
05d8 ט 05d9 י 05da ך 05db כ
05dc ל 05dd ם 05de מ 05df ן
05e0 נ 05e1 ס 05e2 ע 05e3 ף
05e4 פ 05e5 ץ 05e6 צ 05e7 ק
For comparison, here is "unicode 3d0-3e7". It will be fun to watch how
it's rendered.
03d0 ϐ 03d1 ϑ 03d2 ϒ 03d3 ϓ
03d4 ϔ 03d5 ϕ 03d6 ϖ 03d7 ϗ
03d8 Ϙ 03d9 ϙ 03da Ϛ 03db ϛ
03dc Ϝ 03dd ϝ 03de Ϟ 03df ϟ
03e0 Ϡ 03e1 ϡ 03e2 Ϣ 03e3 ϣ
03e4 Ϥ 03e5 ϥ 03e6 Ϧ 03e7 ϧ
In the terminal where I read and write email, they're all as if ‘0041 A’.
But save the email's text/plain to foo.txt and foo.html, add a little HTML
to foo.html, and the browser, here Firefox, presents the Hebrew in both as
05d0 05 אd1 05 בd2 05 גd3 ד
05d4 05 הd5 05 וd6 05 זd7 ח
05d8 05 טd9 05 יda 05 ךdb כ
05dc 05 לdd 05 םde 05 מdf ן
05e0 05 נe1 05 סe2 05 עe3 ף
05e4 05 פe5 05 ץe6 05 צe7 ק
due to the mix of Unicode's strong, weak, and neutral bi-directional
character types.
To see what I intend above needs a ‘broken’ renderer, like a terminal.
For those with more intelligent renderers, it's as if runes normally
drawn as
00c0 À 00c1 Á 00c2 Â 00c3 Ã
became
00c0 00 Àc1 00 Ác2 00 Âc3 Ã
Wrapping each of the Hebrew characters in the text and HTML files in
LRI...PDI,
LRI U+2066 Left-to-right isolate
PDI U+2069 Pop directional isolate
so the first row becomes
0030 0035 0064 0030 0020 2066 05d0 2069 0020
0030 0035 0064 0031 0020 2066 05d1 2069 0020
0030 0035 0064 0032 0020 2066 05d2 2069 0020
0030 0035 0064 0033 0020 2066 05d3 2069 000a
has Firefox display the tables as intended. Perhaps the unicode command
should do this to ensure correct display, especially if some terminals
ever start to improve?
I note that vim(1) here doesn't realise LRI and PDI are zero width
so the cursor position drifts past the end of the visible line.
ed(1) copes without a murmur.
--
Cheers, Ralph. 
11 May
11 May
2:47 p.m.
New subject: {TUHS] Interesting Commentary on Unix from Multicians
On 4/9/22 13:45, Douglas McIlroy wrote:
Interesting, I had not heard about this before, and an internet search
turned up:
(some copy of "Algorithms in C++", by Robert Sedgewick)
https://apprize.best/science/algorithms_2/3.html
paragraph 4.3.23: graphs(4) -> mst(3) -> vyssotsky(23)
https://github.com/reneargento/algorithms-sedgewick-wayne/blob/master/src/c…
(an implementation of this by Rene Argento?)
Algorithms in Java, 3rd edition (2003) R. Sedgewick
20.72: Exercises:
[V. Vyssotsky] Develop an implementation of the algorithm discussed in
Section 20.2 that builds the MST by adding edges one at a time and
deleting the longest edges on the cycle formed (see Exercise 20.34). Use
a parent-link representation of a forest of MST subtrees. Hint: Reverse
links when traversing paths in trees.
I was unable to fetch this slide deck
https://web.archive.org/web/20081205054614/https://www.cs.princeton.edu/~rs…
which also appears to mention it at least in passing: "Other MST
algorithms VYSSOTSKY (1960s) add edges one at a time delete longest on
cycle formed"
Does anyone know of a more complete source on this topic?
It is not mentioned on Wikipedia, these seem like appropriate places to
place a reference:
https://en.wikipedia.org/wiki/Minimum_spanning_tree
https://en.wikipedia.org/wiki/Victor_A._Vyssotsky
Single Level
Storage is an awesome concept and removes so many ugly
hacks from algorithms that otherwise have to process data in files.
This was Vic Vyssotsky's signature contribution to Multics, though in typical
Vyssotsky fashion he never sought personal credit for it. Other awesome
Vyssotsky inventions:
[..]
A minimum-spanning-tree algorithm quite different from the well-known methods
due to his colleagues Bob Prim and Joe Kruskal, again unpublished.
921
days inactive
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11 comments
9 participants
participants (9)
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Alan Glasser -
Dan Cross -
Douglas McIlroy -
Joe -
John Cowan -
Ken Thompson -
Larry Stewart -
Ralph Corderoy -
Rob Pike