13 April 2010 20:16 -
Finally I have some time again to write a blogpost. February and march were busy months in which
I moved from Enschede to Delft. Main advantage of this is of course that I live closer to my
work, which on average safes me around 12 hours a week of travel time. Another advantage
is of course that the house is larger (around 30 m^2) and do not have to park my car 10 minutes
away.
But that was not all that happened in the last 2 months. I also passed the PRINCE 2 Foundation
exam on the 19th of february.
Beside the PRINCE 2 Foundation exam I also received some Novell certification.
Due to my LPIC certifications I became a Novell Certified Linux Administrator and
a Novell Data Center Technical Specialist.
01 January 2010 09:44 -
As always at the beginning of the new year I look back at the previous
year in numbers. This time 2009.
Car
In 2009 a drove over
26,427 kilometers by car. A drop of
2.12%
compared to 2008. Based on the average diesel oil usage of my car this
amounts to over
1,638 liters of diesel oil used.
The highest GPS speed reached with my cars was 196 km/h.
I got a total of 1 speeding tickets (66% decrease compared to 2008),
for a total amount of 68 euro (a 60% decrease compared to 2008).
Speeding saved me around 25 hours, which makes the cost of speeding
around 2.72 euro per hour saved (Which makes it economically feasible).
1 person managed to damage my car, while it was parked. A decrease of 50% compared to 2008.
Running and cycling
I ran more than
14 kilometers an increase of
350% compared to 2008.
I cycled more than 192 kilometers a decrease of
82.71% compared to 2008. I had 1 flat tire while cycling.
The highest speed reached by bike was 51.47 km/h (23% decrease compared
to 2008). The highest average
speed was 25.33 km/h (10.24% decrease compared to 2008)
over a 20.37 kilometer track.
The longest track cycled was 52.2 kilometer.
Communication
I was on my cellphone for more then
33.5 hours a decrease of
29%
compared to 2008.
I typed more than 1,917,907 characters on IRC and twitter an increase of
103% compared
to 2008.
Travel
I traveled over
600 kilometers by plane a drop of
40% compared
to 2008.
I traveled over 65,504 kilometers by train a drop of
1.60% compared
to 2008.
I visited 3 foreign countries (Germany, Belgium and the United Kingdom) an increase of
50% compared to 2008.
Health
I slept approximately
2,752 hours. An increase of
2.32% compared to 2008.
My average heartbeat in rest was 63.22 beats per minute. Which is
an 5.72% increase compared to 2008. This of course means that my heart beat more than
33,228,432 times in 2009.
My average weight in 2009 was 55.60 KG. Which is a drop of
0.215%
compared to 2008.
My estimated Vmax in 2009 was on average 36.53. Which is a decrease of
0.84%
compared to 2008.
My ability to lift weights increased by 17% compared to 2008 (times *
amount).
Other
I did
708 commits to my private subversion repository a decrease
of
26.76% compared to 2008.
I went shopping more than 76 times an increase of
1.33%
compared to 2008.
I completed 68 private projects an increase of 106% compared to 2008.
I logged in to remote hosts using ssh more than 7,308 times. A decrease of 44.5% compared to 2008.
I wrote 16 blogposts in 2009, 12 less than in 2008.
I read 24 books. Which amounts to over 10,000 pages.
The longest time of having no connection to the internet was 72 hours.
I watched 30 movies in 2009.
03 November 2009 19:41 -
Since I replaced my trusted Treo 650 with a HTC Hero, I decided it became time that I would have
a possibility to sync my calendars between my phone and my laptop. My laptop being a Mac,
this quickly boiled down to a sharing solution with iCal support. Unfortunately, the HTC Hero
can only connect to Exchange, Outlook and Google Calendar.
Using Google Calendar was of course not an option. I do not want to store my private calendar data
on the servers of a company like Google. From the HTC Hero perspective that only left we with the
Outlook/Exchange choice. As mentioned before, I also want to sync my calendar with iCal on the Mac,
hence the only possible solution seemed to be
Zarafa.
Setting up
Zarafa proved to be straight forward. I just followed the following steps:
- Install a Centos 5 host on a kvm machine using netboot
- Run yum update on this machine and reboot.
- Download the Zarafa Community edition (I do not need more than 3 users)
- Follow the Zarafa installation manual
- Enable zarafa-ical
- Made the machine reboot proof by enabling the zarafa services with chkconfig
During this I ran into 2 very very minor problems. First of all the manual did not
state that you had to extract the .tar.gz file. This is of course logical step to take, but
I am a little picky about the correctness of manuals. The second issue was that
sysstat is not mentioned in the dependencies of
Zarafa in the manual.
After the fixing of said problems,
I had a working
Zarafa server which could sync with iCal.
For syncing with the HTC Hero I had to install
Z-push on the server to be able to use active-sync.
The installation of
Z-push looked very easy, however after following the installation manual and
configuring the HTC Hero I ran into the following error:
Account could not be created, please try again later.
After some searching I found the solution
here.
And now it works like a charm.
03 May 2009 16:57 -
Sometimes you are just chatting on IRC and hear that some people still use passwords that appear
in quotes on IRC and are mentioned in various IRC channels. If you are fully aware of that,
you should of course not use that password for anything. Especially not for anything that can
be considered confidential.
The above points seem obvious, but to illustrate the effect this can have I will give an example:
Imagine you are the chairman of a well known hosting community providing virtual private servers. Lets
call this community '
zoloos'.
Further more, imagine that you use a password that has been mentioned in:
#linux.nl, #alcohol, #cafe and many other IRC channels as your
password. And to make things worse, even imagine that the password is
mentioned in quotes.
What will happen then? Well the following information may get publicly known:
- The personal information of all zoloos members.
- The confidential minutes of zoloos meetings.
- Passwords of various zoloos services. I.e. the zoloos cacti and zoloos zabbix.
- The configuration of the zoloos switch.
So please choose good passwords and change them regularly.
Thanks to
Hepp,
BugBlue and of course Cinder, who quickly locked the account.
09 February 2009 18:48 -
Just thinking of it: The average dutch person commutes 2 x 39 minutes a day. Which totals
to 78 minutes. The average dutch person watches 182 minutes of TV per day. Total amount
of watching TV and commuting 260 minutes per day (aka 4 hours 20 minutes).
So lets take in account the time I commute (4 hours 45 minutes) and watch
TV (none or I watch TV while commuting). Also part of my commute time is work
time (1 hour 15 minutes).
The funny thing is the average person says I have a long commute time. So lets calculate
the time left per day when removing commute time, TV time and work time (based on 8 hours a day).
Average dutch person: 24 * 60 - 78 - 182 - 480 = 700 minutes per work day
Me: 24 * 60 - 285 - 0 - 405 = 750 minutes per work day.
04 February 2009 08:09 -
Last week I thought a little about naming volumegroups on SANs, logical volumes,
hosts and (micro)SD cards. They all have one thing in common, if you have a lot
of them you hardly can avoid numbering them. The only problem with this is of course
small typos that can lead to disasters. Fortunately there are of course solutions for this.
After some thinking I thought about using checksums in the numbering, which makes
it harder to create a disaster with just one typo. The best scheme I could find
to work for this was using the ISBN numbering scheme.
So i.e. I now number my (micro)SD cards as follows:
- jni-60001
- jni-10002
- ...
- jni-12761
- jni-72762
- jni-22763
- etc.
As you probably can see the first number is the checksum digit. A number is
valid if and only if the checksum digit + 2 times the second number + 3 times
the third number + 4 times the fourth number ... modulo 11 = 0. Note that the checksum digit
can also be X to indicate a value of 10.
If you look at the jni-60001 number. The checksum is 6. And the 1 is multiplied by 5. Summarized
this makes 11, which modulo 11 is of course 0. So this is a correct number. But what if we make
a typo i.e.:
- jni-60010, this becomes (6+4) modulo 11 = 10, which is not valid.
- jni-60002, this becomes (6+10) modulo 11 = 5 , which is not valid.
- jni-60019, this becomes (6+4+45) modulo 11 = 0 , which is valid. But then you already have
made 2 typos.
Of course I created a script for this that does all the hard work. It can be found
here.
02 January 2009 17:32 -
As always at the beginning of the new year I look back at the previous
year in numbers. This time 2008 in numbers.
Car
In 2008 a drove over
27,000 kilometers by car. A drop of
10%
compared to 2007. Based on the average diesel oil usage of my car this
amounts to over
1,674 liters of diesel oil used.
The highest GPS speed reached with my car was 198 km/h.
I got a total of 3 speeding tickets (50% increase compared to 2007),
for a total amount of 170 euro (a 227% increase compared to 2007).
Speeding saved me around 25 hours, which makes the cost of speeding
around 6.80 euro per hour saved (Which makes it economically feasible).
2 persons managed to damage my car, while it was parked. One
of these persons attempted to to steal my navigation system. The other
one should practise parking a car.
Running and cycling
I ran more than
4 kilometers a drop of
98% compared to 2007. Mainly
because I focussed more on cycling.
I cycled more than 1,113 kilometers an increase of
271% compared to 2007.
I fortunately had no flat tires.
The highest speed reached by bike was 67.56 km/h (39% increase compared
to 2007). The highest average
speed was 28.22 km/h (15.65% increase compared to 2007)
over a 22 kilometer track.
The longest track cycled was 127.78 kilometer.
Communication
I was on my cellphone for more then
47.5 hours an increase of
48%
compared to 2007.
I sent 1,206 sms messages.
I posted 0 messages to usenet a drop of 100%.
I typed more than 943,230 characters on IRC a decrease of
9.76% compared
to 2007.
Travel
I traveled over
1,000 kilometers by plane a drop of
50% compared
to 2007.
I traveled over 66,572 kilometers by train a drop of
5% compared
to 2007.
I visited 2 foreign countries (Germany and France) a drop of
60% compared to 2007.
Health
I slept approximately
2,690 hours.
My average heartbeat in rest was 59.8 beats per minute. Which is
an 10% increase compared to 2007.
My average weight in 2008 was 55.76 KG. Which is a drop of
0.214%
compared to 2007.
My Vmax in 2008 was on average 36.84. Which is an increase of
4.27%
compared to 2007.
My ability to lift weights increased by 36% compared to 2007 (times *
amount).
Other
I did
784 commits to my private subversion repository a decrease
of
26.73% compared to 2007.
I celebrated my birthday 1 times.
I went shopping more than 75 times an increase of almost
14%
compared to 2007.
I do not know how many garbage bags I threw away because of the
breakdown of 1 counter on the container.
I completed 33 private projects a drop of 72% compared to 2007.
I logged in to remote hosts using ssh more than 13,168 times.
I wrote 28 blogpost in 2008, 1 less than in 2007.
I got 1 nephew.
I read 28 books. Which amounts to around 8,400 pages.
The longest time of having no connection to the internet was 72 hours.
17 December 2008 08:53 -
Since a few days I have a Sony HDR-TG3E from my employer. The target is to get
an hour of movie material per consultant about the company. The material of all
consultants will be gathered to make a professional promotion movie.
My idea for my material is to make a 24 like clone, which when put in a one hour movie will
result in 2.5 minutes of material per real hour. There are how ever some challenges I have to face:
- How to keep it interesting. That is I have to come up with a good plot.
- Writing a sharp and humorous dialog, while in the mean time give a real
impression of what my work is like.
- Security,
privacy and NDA regulations. Which means that I can not shoot and/or publish
all material I want or need.
Anyway,
casting has started. So if you want to play the role of jnieuwen girl (in
parody of the Bond movies :)) send an email to casting@jeroen.se
Stay tuned for the trailer. The movie should be ready near the end of 2009.
26 November 2008 19:04 -
Sometime you can easily get someone confused. I.e. a colleague who accidentally
changed the owner ship of all the directories in the /home directory of a
system (non recursive). His question: "How can I fix this?".
Our answer:
ls -ld * | xargs -n 1 -Iwithouta chown withouta:withouta withouta
or how we had to say it in words: l s space minus l d space star space pipe space
xargs space minus n space 1 space minus capital i without a space chown space
without a colon without a space without a enter.
05 November 2008 18:22 -
After a lot of complaints on IRC that I did not have an hyves account, I finally created one.
It can be found at
jnieuwen.hyves.nl. The posts from the
jeroen.se blog are also available on hyves. For the rest I still
have to send some hyves invites, and set more profile information.
So if you have a hyves account and want to be a friend on hyves, do not hesitate to send
an invite.
06 October 2008 18:35 -
Today on IRC someone claimed that there is a mathematical proven algorithm to win money
with poker in the long run. I can not believe this is true because of the following:
Assume we have the algorithm A that guarantees a certain win when playing
poker. Now imaging 4 poker players. Each starting to play with an
starting amount of X euro against each other in a room. Each player plays
according to algorithm A, because that will guarantee him a certain win of
money over time.
Given by the rules of poker: The amount that can be won in a round (W) by a player
is equal to the amount lost in a round by the other players (L).
After 0 rounds the total amount of money in the room will still be 4X euro. Trivial.
After n+1 rounds the amount of money in the room is the amount of money in the
room after round n + W - L. Which gives Mn+1 = Mn + W - L. Given that W = L we have that
Mn+1 = Mn.
So after n rounds with n a natural number >= 0 the total amount in the room is still 4X.
Assume that algorithm A works and g is the average amount gained by each player
per round. If A is true than g > 0. Hence after n rounds (with n > 0 and sufficiently large),
every player has on average X+gn. Which means the total amount in the room
would be 4X+4gn with n > 0 and g > 0 after n rounds. Earlier we have proven that
for every n the total amount in the room is 4X. Therefor we have that:
4X+4gn = 4X for every value of n. But 4X+4gn > 4X for every n > 0,
hence the assumption that algorithm A works is false.
01 October 2008 21:30 -
Today I launced a new layout for jeroen.se.
A few pages have disappeared in this process,
but some of them will return when I have decided how to redesign them.
23 September 2008 20:55 -
Today it is 5 years ago that I registered the jeroen.se domain.
09 July 2008 13:23 -
Just a quick blog post about how to run a command like uptime in more than
one screen window. Just do crtl-a then
:at "#" stuff "uptime\015"
24 May 2008 13:57 -
Today my blog is 1 year old.
20 May 2008 07:58 -
For reading and organising my email I use mutt. In the past I have used mail.app for
a while, but it had to much problems for me. Using mutt however I had one
little irritation. Saving email to my next and waiting for mailboxes
was cumbersome. It takes to much keypresses or hard to remember key short cuts.
The simple solution I came up with was to make symbolic links in my Maildir. I.e.
ln -s .next .n, which allows me to type the command
s=n in mutt instead of s=next.
So what do I gain by that: With approximately 3 emails a day to file
this way, I save 1095 keypresses per year. With an average life expectation
of around 75 and an current age of 29 I save 50370 keypresses in my life. Being able
to type with around 200 keypresses per minute I save 4 hour, 11 minutes
and 51 seconds.
24 April 2008 08:29 -
Monday I passed the Introduction to Oracle SQL and PL/SQL exam. So time for a week
of rest and then going to work on the exams to become an Oracle Certified Associate.
01 January 2008 16:29 -
The year 2007 in numbers
- I traveled over 30000 kilometers by car
- I traveled over 2000 kilometers by plane
- I traveled over 70000 kilometers by train
- I ran more than 200 kilometers
- I cycled more than 330 kilometers
- 245 km/h was the highest speed at which I drove a car (note: gps speed)
- I visited 5 foreign countries (Belgium, Germany, France, Ireland, Denmark)
- I was on my cellphone for more then 32 hours
- I posted 57 messages to usenet
- I typed more than 1045236 characters on IRC
- I did 1070 commits to my private subversion repository
- I celebrated my birthday 1 times
- I went shopping more than 66 times
- I threw away 35 garbage bags
- I completed 118 private projects
- I got 2 speeding tickets for a total amount of 52 euro
11 November 2007 20:24 -
Today Tijmen Ruizendaal released the latest version op typingspeed.pl. It has
2 major improvements. First a fix for a memory leak. The second improvement
based on my code is the logging of your typing speed to a file. This allows
you to make nice graphs of your typing speed. Read all about
these changes and more
here.
31 August 2007 17:58 -
This week I switched back from the Apple mail client Mail.app to mutt. I have tried Mail.app for
several months. And it does have its good points. However I want to keep and send my email in
plaintext format. Unfortunately Mail.app seems to think it has to save my plaintext email
in some kind of html format when I put it in the drafts box. So back to mutt.
The only problem this introduces however is that I currently do not have an option on my macbook
to read mail in offline mode. So I am currently on a quest for a mailclient which does not have
the Mail.app problems and that I can use in combination with mutt. I will probably give thunderbird
a try.
19 June 2007 17:29 -
Today I played a little with vim syntax files. So I created a simple one to have some colors in
my
todo list.
Here it is:
syntax clear
syntax case ignore
syntax match jnieuwenPerson / [^:]*: /
syntax match jnieuwenCategory /^[^:]*/
syntax match jnieuwenDate /[0-9]*-[0-9]*-[0-9]*/
hi jnieuwenPerson ctermfg=yellow
hi jnieuwenDate ctermfg=red
hi jnieuwenCategory ctermfg=green
29 May 2007 17:24 -
This weekend I had the problem that I had to check several hosts on a network
behind NAT with nagios. One solution would be to add portforwardings on the NAT
firewall for each host and use check_nrpe with different port settings from the
nagios machine. This is of course a maintenance nightmare.
The solution that I choose was therefor a little different. I installed nrpe
server and the nrpe plugins on all hosts. Then a portforwarding to port 5666 of
one host (irobot) was added in the firewall. In the nrpe config of irobot I
added the checks for irobot and checks for the other hosts by adding lines like
these to the nrpe.cfg of irobot:
cammand[vacdepot_fs_root]=/usr/lib/nagios/plugins/check_nrpe -H vacdepot -c check_fs_root
In the nrpe.cfg of vacdepot check_fs_root is defined of course.
So I am using nested nrpe calls to get the data I want. The advantage being
that I do not have to have a portforwaring for every host I want to monitor
behind the NAT firewall.
