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Thursday, February 1, 1996
Oops, yesterday I thought it was the first of February. I quickly fixed
it. Also received mail from Bert which he send from Japan. They arrived
safely and had a warm welcome. They got a nice apartment. He will
be working at the
Computational Sciences Division of the
National Aerospace Laboratory.
Monday, February 5, 1996
(Especially for those outside Holland reading this:)
It is still snowing, although it is not so cold anymore. But what is
more remarkable, is that the snow has remained for almost 10 days now.
I have been thinking about announcing this diary on the
comp.infosystems.www.announce news group.
This is part of Fractal intuition by
My min_ruler.c program
is using up all the otherwise wasted computer cycles of the
glasshotel.cs.utwente.nl. Although, it runs on the lowest
priority, it used about 92% of the CPU (and only 0.5% of the memory).
I found this in a posting by Peter Seebach in comp.lang.c:
In article <email@example.com>, HOTARD <jhotard> wrote:
>I am writing a program that looks at a character and then determines if it is a
>letter or number. This program must use the switch command ...
int c, x, printf();
c = getchar();
switch (x = ((c = (unsigned char) c), /* try to ensure a legal char. */
((!!isdigit(c)) << 1) | ((!!isalpha(c)) << 0)))
(x == 0 ? "'\\x%x' is neither a letter nor a number.\n" :
(x == 1 ? "'%c' is a letter.\n" : (x == 2 ? "'%c' is a number.\n" :
(x == 3 ? "'%c' is both a letter and a number.\n" :
"'\\x%x' is odd.\n"))), c);
Tuesday, February 6, 1996
Mattijs de Vries offers his home build
Quad 405/II VSE poweramp II for sale.
Today was the first time she did not cry/complain anymore when
going into bath, since I freighted
her. She even smiled a little.
Wednesday, February 7, 1996
Sometimes, people in their enthusiasm can lurk
into rather popularistic writing style in a serious scientific
report, and say things like:
`Now read the rule again carefully'
(red-lining by me).
When I read this page in the report, it gave me the giggles.
[Added on February 8:]
But do not understand me wrong. I do respect the person
who wrote this very much. His knowledge about the English
language is far superior to mine. Not so long ago, he said
to a student: `You are the first student, who wrote a flawless
paragraph'. I got the impression that the student did not grasp
the extend of this compliment. Up-to-today, I have not
been able to follow the student's example. I also do not have the talent
for writing, which this person has, because sometimes he
produces a paragraph that would have taken me hours.
Embedded wierd C program
Kenneth A Reek wrote
a posting to comp.lang.c:
In preparing some materials for a course, I wrote the following
program to illustrate that the order of expression evaluation is not
determined completely by the precedence of the operators involved. I
ran it on every compiler I could find and, not surprisingly, got lots of
I'd like to get results from this program for as many different
compilers as I can to drive home the point that expressions of this
sort must be avoided. If you have access to a C compiler other than
the ones listed below, I'd be grateful if you could run this program
and send me the results. Please include the operating system you are
using (if appropriate to the identification of the compiler) and the
compiler version number if it has one.
Here's the program (hold on to your hats):
int i = 10;
i = i-- - --i * ( i = -3 ) * i++ + ++i;
printf( "i = %d\n", i );
Results found to date:
21 Borland C/C++ 4.0, Turbo C++ 4.5
-86 Sun 3/50 cc
-85 Sun Sparc cc, SunOS 4.1.4 (a K&R compiler)
4 Sun Sparc acc, SunOS 4.1.4 (an ANSI compiler)
36 DEC VAX/VMS
21 Silicon Graphics Indy, IRIX 5.3
-63 gcc 2.6.3
I could add:
-63 gcc version 2.4.5
Thursday, February 8, 1996
On Monday, I wrote that I was thinking about
announcing this diary on comp.infosystems.www.announce news group. The funny thing
is that Bernie Wilt did announce his
links to diaries on the net.
Francisco van Jole
must have read this announcement, and found
my diary, because he mentions it in
of Daily Planet,
a Dutch mailing list with interesting pointers to things on
the InterNet (in Dutch) provided by
I wonder how many people are going to read my diary now. If you
are reading this, please let me know what you think of it. So far,
I have never got any email referring to my diary.
Someway, I have always thought that only people from the other side
of the world would read my diary pages, but now there might be many from
inside Holland (I should say the Netherlands) that are going to
read my pages.
Again this makes me ask myself the question (that I have asked myself
many times before), why do I have this desire of writing my thoughts,
ideas and experiences down, and even in a place where it could be
read by complete strangers, or what might be worse, people who
know me a little.
A pale winter sun
I just opened the blinds to enjoy the last bit of a nice winter sun
going down. The blinds are outside, and can be controlled manually
with two buttons on the inside. Although, you can let them go down
and up by themselves automatically (determined by the amouth of light
and wind), but it seems that nobody is using this functionality
anymore. The reason is that the sensor for measuring the amouth
of light is somewhere on the roof of the building. If there would
be one in each room, it might have worked slightly better.
Friday, February 9, 1996
This morning I woke-up at 6 o'clock in the morning, realizing that
it was lighter than usual in the room. I had left the
curtains open yesterday evening. Our bedroom window looks out to some
field, and the next houses are at least 100 meter (yard) away.
Before I got married, I never closed the curtains, but
it. The light I saw was from the street lights reflected on the clouds
At half past 7, I heard on the morning news that it was freezing 20 degrees
Celsius outside. Li-Xia told me that we had three woolen caps,
that I could use. I picked the one with
on it, and used
an extra shawl. But still my eyes were tearing when biked to the
I had to think about all those people living in Eastern Europe, who
would consider -20 a warm winter day.
Monday, February 12, 1996
The story of Annabel
crying in bath, was mentioned yesterday during
the broadcast of the Online radio show, on the Dutch Radio 1 channel. Three days before she will turn 16 months (on Valentines
Day) she made it on the national radio. That is a record in the history
of our family!
(See also last Thurday's entry for an explanation of how this came to happen.)
Because I did not record the broadcast, I emailed their
and asked whether they could provide me a copy on tape. I was
very happy, when I received an email from Yvonne van Bellen, to tell
me that they send one for free! Thank you!
This morning I saw a new new group with the name alt.magick.serious.
I don't believe that the person(s) who created this news group have
a good understanding of the USENET. The only way to get a serious news group
is to pick a very boring topic of discussion, or create a news group with a
name that does not say anything about its subject, and only reveal the
name to restricted number of people. (But even that does not work in
the long run.)
Today, we had agreed to finish a document we have been working on
for some time. At these kind of times, disaster is likely to strike.
Only 15 minutes ago, Susan came in running
in to tell me that the solution I had provided for an example did not
When I looked at it, I had to agree that she was right. (So,
was Justus, who had pointed
out the problem at first in an email.)
Studying it more, we came to the conclusion that we either had
to remove the example, or modify the solution a lot (and still not
being sure that it was correct).
Then I suggested to modify the example slightly, by adding `i, '
at the proper place. Then we looked at the solution together, and
it turned out, we only add to add `!i ', and nothing else.
Which came as a surprise to both of us.
Valentines day, February 14, 1996
This seems to be a very important day. I printed out my Valentines
card that I had made on January 31, so
I can give to Li-Xia, my girl-friend.
Yesterday evening, while doing the dishes, I heard some older man
on the Radio refer to his `girl-friend'. Without thought, I assumed
that he was not married, but probably living together with her.
Then I realized that I always talk about Li-Xia as `my wife'.
Suddenly, I realized it would be better to refer to her as my
girl-friend, because she is my best female friend.
Steve Mann shows some of
his private views:
(the latest he transmitted.)
Friday, February 16, 1996
One nice thing of an electronic diary is that you can rewrite it.
I try to stick to the rule that I should not edit pages written
on a previous day (except for the `next entries' links), but
some times I take the freedom to modify something, because of
the public nature of this diary, especially, when the things that
I wrote are related to other people.
However, I feel completely free, to write the things on a page
in any order I like. The remark about LOTOS below, was written
before I wrote this.
The return of Guilds
It is funny to see, that with the existence of the InterNet
guilds are returning. Some time ago, I already found
the International Programmers Guild.
Today I found the
HTML Writers Guild.
And what to think of Declaration of Independence! by
Computer Science: One of the most abstract sciences
I more I get into computer science, the more I get convinced
that it is one of the most abstract sciences. If I talk
about `computer science' in this context, I refer to the
concept and methods that are used, not about computers or
computer applications. The average user of computers (or the
InterNet) do not have to know (and usually, do not know) anything
about (theoretical) computer science, just like you do not
have to be a linguist to be able to speak a language.
Currently, because computer science being a very young science,
this is best seen in the confusion that is caused by
terminology. If you are a computer scientist, tell me
the meaning of the following words: process, task,
object, interface, activity and method.
(Probably, you can come up with 4 or 5 definitions for each word,
especially if you think about other sub-fields of research.)
It would be funny to write a `Concise Computer Science Dictionary'.
Please skip this section if you never heard of
We are using LOTOS in the TransCoop project, as one of our specification languages.
LOTOS is an process algebraic language which is based on the concept of
synchronization events between processes. Although this is a very
powerful concept to model complex behaviour, it does have certain
limits in the high-level specification of realistic systems.
In such specification, one would like to use a gate (= a channel
on which synchronization events take place) to represent the
interface between a user and an application, where a single event
indicates a operation to be performed, or a message being send.
But this fails, because in case there is no synchronization,
the reason remains unknown.
The idea that gates in LOTOS can be thought of communication channels
between processes, is a misconception that is hard to avoid.
From the design of distributed systems it is known that it
is impossible to achieve synchronization with an finite number
of messages being passed between the distributed components
of the system.
How ever, LOTOS can be used to specify the low-level protocols
that are used to build distributed systems.
I found my brandless calculator in my desk. As I haven't used it in
months, maybe I should take it home. It only costed about 10$.
The reason I bought it (and not some other one in the same price
range) is because it has conversion between binary, octal, decimal
and hexadecimal values. (And, of course, I could play this trick of
converting 1026654 to hexadecimal.)
As a hacker I used to use hexadecimal
to decimal conversion a lot. And yes, I cannot convert 0xAF3E within 10 seconds
to 44862 by heart as some people can.
On Monday the winds turned again, and while I was in Darmstadt (just
below Frankfurt, Germany), the northern part of the Netherlands
was covered under snow again. In Enschede we only had a little,
but there is snow again.
Last Sunday, we went to Darmstadt,
to stay there for two nights and
days. So, my girl friend gave me two pairs
of socks in a bag. I only had a small plastic bag to keep the
socks in, and I was forced to use it for both the fresh and used
So, on Monday morning I sat on the side of the bed and looked
in the bag, containing two pairs of unused socks, and immediately saw which
pair I had to pick, in order not get confused, and know which was
the unused pair the next day. Now, you have to know that I have
a bad memory for small details, so marking the socks (by folding
them in a special way might not work). I put the new socks on,
and put the used pair in the bag with the unused pair.
(Notice, that however, that in case I would have had two bags,
as most people do, I might have confused the bags, which would
both contain one pair of socks.)
On Tuesday morning, I looked in the bag again, and I had indeed
forgotten which was the used pair, or how kept them apart. But
then I recalled that there was a logical way of determining which
was the one that I should put on. And there was only one, and soon
I knew which (clean) pair of socks I had to put on.
The riddle is: How could I have done this?
This riddle has been posted in rec.puzzles.
Listen to the worlds fastest talker.
Friday, February 23, 1996
I just cleaned my desk (we just finished an important
and found 9 pens, and a cap, partly covered under my papers. I am
quite sure that it must be more than a year ago that I got some
new pens. As most of them are still working, I am forced to conclude
that I stole (or at least unconsciously took) them from my colleagues.
So far, I did not see any solutions, except for sniffing and
folding methods (which I did not use). A small hint:
The riddle says that I looked in the bag, and that I
immediately saw which pair I had to pick. The
most obvious visible attribute of a sock is colour.
I found a page about him through a page about
Capital punishment. Reading his
made a big impression on me.
I came to this page, because yesterday I send an email
to The Honourable Lawton Chiles,
Governor of Florida, with respect to death penalty of
Sunday, February 25, 1996
The Wedding of the Lord
Today Eddie Bakker preached on
A traditional Jewish Marriage
Whenever a young man wants to marry a girl, he goes to
visit her father, to discuss the dowry. If he and the
father of the girl have agreed upon the dowry, they
drink a glass of wine to seal the agreement. From
that moment the young man and the girl are engaged,
which is considered equal with being married.
The young man goes home to build and prepare a house,
which consists of one or more rooms attached
to his fathers house. It is his father who determines
whether the new rooms have been prepared correctly.
Then the young man goes with his friends to catch his
bride (together with her friends). This catching is
almost a kind of stealing, and he takes her to their
new rooms. After they have gone into their new rooms
and they have become one in mind, body and spirit the
wedding feast starts, which usually takes several
days up-to several weeks, depending of the wealth of
the young man.
There is a striking resemblance between this wedding tradition
and the story of Jesus with
the church as his bride.
- Jesus drink wine with his disciples at the last supper.
- He paid the highest price, by giving His own life.
- He returned to His Father to prepare rooms for His bride.
- He will come back, as a thief in the night, to get
- There will be a great wedding feast.
Personably, I find this one of the most remarkable chapters of the
Old Testament. It speaks in such an accurate way about the
(fallen) spiritual state of man, that it cannot be the result
of mere human thought. This is definitely one of the chapters
that proved the divine inspiration of the Bible.
The three kinds of temptations
Compare Gen. 3:6, 1 John 2:16, Math 4:1-11, and Luke 4:1-13.
- The lust of the flesh.
`The woman saw that the tree was good for food'.
was tempted to turn stones into bread.
- The lust of the eyes.
`The woman saw that it was a delight to the eyes'.
Jesus was shown all the kingdoms of the world.
- The boastful pride of life.
`The woman saw that the tree was desirable to make one wise'.
Jesus was tempted to take pride in that the angles would
protect Him from harm.
Monday, February 26, 1996
There came some answers in the
rec.puzzles news group.
Charles Bryant wrote:
You had two identical pairs of socks, and an extra pair. For example,
four red socks and two blue. Sunday's socks were red, so you deduced
that if you were to wear the blue on Monday, you wouldn't be able to
tell the fresh and used red pairs apart on Tuesday. Therefore you left
the blue pair for Tuesday.
This would work if you had a good memory, but he stated that he had a
bad memory. My assumption was that color, textures, materials (wool
vs. silk) and other markings would be non-helpful; Therefore he would
have to choose the new pair from current means rather that a past
memory. (i.e. smelling them!). :)
David Conrad then
Charles' scheme works fine without any memory of colors, textures, etc.
Bravo to all who solved it.
On the first day you wear one pair of red socks, and have a clean red pair
and a clean blue pair in the bag.
On the second day you could pick either clean pair to wear next, but you
realize that wearing the blue pair will leave you with a problem tomorrow,
so you wear the clean red pair, putting the dirty red pair in the bag.
On the third day you don't need to remember which pair in the bag is clean.
You simply compare the ones in the bag with the ones on your feet. The
ones that resemble the pair you're wearing are dirty, the others (blue)
You do need to remember your reasoning from day two (which kept you from
wearing the blue socks second), but you don't need to remember colors.
A small remark though:
On the third day, I did not even remember the reasoning, except that
it was logical. And then I deduced from this what it must have been,
just like the above people solved the riddle. Actually, that I could
deduce it on the second day, gave me the idea to post it as a riddle.
Tuesday, February 27, 1996
Wednesday, February 28, 1996
To what David Conrad
said (see last Monday's entry),
Is this the Official answer? I suppose that this answer is the only
true "canned" answer (even though a selective memory may rub me the
Today, I read a posting by Seth Breidbart
replying to this with:
You don't have to remember your reasoning; since it's reasoning, you
can reconstruct it from scratch.
By the way, Indy mailed me (on Monday) the following, after I had replied
to (by email) his posting on the news group:
Is this the Official answer? I suppose that this answer is the only
true "canned" answer (even though a selective memory may rub me the
wrong way). Actually he could write his reasoning on a note and tie
the note to his finger, but he would have to remember to read the
note! .........Thanks for your reasoning!
I replied to him (by email), and said the following:
As I am the poster of the riddle, this can indeed be considered as
the official answer, although I could say some more about it.
(For example, explain how other combinations of coloured socks
would not have worked, and so on ...)
I just came back from a talk by Weike Wehrhein about `Specifying reactive
systems with action dependencies'. From the name I had not guessed that
she was a woman. During the talk, I got the impression that she
was pregnant. (What if I am wrong? Susan
was not convinced.)
The Fragment was taken from a colour picture. I do not believe
that anybody can find the original picture it was taken from,
although it is only about 5 steps (search engines excluded) from one of
The fact that people were able to solve the riddle, proves that
I did not need any information on Tuesday, except that there
was a logical argument involved. It was then that I realized I
could post it as a riddle.
I made some vanilla flavoured tea for myself, which is produced in Holland
by Arcus B.V. in 's-Hertogenbosch. I am just trying to get my first C++ class
definition compiled, which are part of a scanner/parser
for the CoCoA language we designed as part of the
Thursday, February 29, 1996: Leap Years Special Day
I played with the
model train of the Univeristy of Ulm.
At the end of the afternoon, Susan came
to show me a drawing
(redrawn with xfig)
which she used to explain something
Or in other words:
Coorporation without notification implies isolation and loss of work.
(next leap day)
January 1996 |