Posts Tagged ‘generation’

The brief story of information according to James Gleich – and how we possibly come to be at where we are

Saturday, June 23rd, 2012

We're living at a times, where information has become more valuable than money and gold. Though we're living in a such a wild changing times, still it is not easy to answer in onefold clear way what is information.
The more the world and humanity developed the more meanings information word accepted.
While checking some interesting videos on the net, I've come across a video representing in a very brief form the history of information.

The Story of Information and how we come to be at where we are now

We're living at a times, where information has become more valuable than money and gold. Lest that living in a such a wild changing times, still it is not easy to answer in onefold clear way what is information.
As you can see from the video, the more the world and humanity developed the more meanings information word took up.

At the end end of the short presentational video there are few questions asked:
 

  • Who coined the term MEME
  • How many zeros are in yottabyte?
  • What is a one thing that can escape a black hole?

I did a quick research on the newly heard words and came to know meme concept. A meme is an "an idea, behavior or style that spreads from person to person within a culture.". The theory lists some interesting information like replication of personality (propagation) from one person to another etc. etc. However the general content of meme's theory puts Christian faith, religions and all kind of people beliefs in the graph of being just a continuous meme's patterns which are transferred from a person to person (generation to generation). Therefore according to memetics (as the meme's science is called), Christian faith and even my Orthodox Christian faith is just an informtion transmitted similarly to genetics information and the laws against:; sexual morality, bestiality, adultery, castration etc. are just a taboo and makes not sense and is just they claim is a information transferred from family generation to next generation until today.

Obviously the whole "theory" of memetics as a science is not true and is just a world view of Mr. Richard Dawkins in a book called The Selfish Gene (1976). It is well to be said Dawkins a follower of the fairy tales of Charle's Darwin's Darwinism.
Modern science however is seriously questioning Darwin's materialist world view. There are plenty of scientific researches which has prooved the existence of spiritual realm and hence some of the claims memetics are standing on a shaky grounds.

Concerning the second question in the video how many zeros are in an yottabyte the answer according to FreeFactFinder.com is:

2^80 = 1,208,925,819,614,629,174,706,176 bytes = 1024 zettabytes.

So having in mind the yottabyte equals 1,208,925,819,614,629,174,706,176 bytes if in bytes it would have 2 zeros :)

But if by zero is meant the number of values which could become zeroes then the answer would be 24 zeroes. This of course is in bytes in zettabytes the zeroes are only 0 or 3 i.e. (1024 zettabytes) :)

Moving back to the 3rd video question What is a one thing that can escape a black hole?. The answer is "WHO KNOWS ??".
The BlackHoles are a matter of science based on a huge theory base, there are plenty of discussions by some scientists still doubting if black holes really exist ,,, even if we assume blackholes exist noone can tell if the blackhole would suck up all matter (including light) or some specific kind of still un-researched matter or energy can get out… In short the question imposed is completely ridiculously funny ;)

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GPL Arcade Volleyball – DOS Volleyball oldschool game remake for GNU / Linux

Wednesday, December 21st, 2011

Do you remember that oldschool Arcade VolleyBall game which was so popular on 16 bit (8086 XT) computers.
I remember this game from the years I was 12 years old, back in the days where we the gamers distributed all the DOS games on 360 KB 5.25" diskettes

I was looking over the games available to install on my Debian GNU / Linux today just to be happily suprised to find GPL Arcade Volleyball an identical game remake of the old Arcade Volleyball 8086 classic freeware game.

I remember we spend many hours with friends playing on the old Manifactured in Bulgaria Pravetz 16! computers
During communism and post communism Pravetz was the only computer brand we could buy from the market, as there was limitations on the exported and imported tech equipment within the USSR union.
Pravetz computers are a literal remake of 16 bit IBM 8086 computers and the computer design and integrals was stolen from IBM 16 bit 8086 / 8088 PC architecture

Arcade Volleyball has set a mark on my generation and I believe many people will remember the times this game was a hit with a bit of Nostalgia ;)
In the Game GPL Arcade Volleyball Debian GNU / Linux

Besides being an identical remake of PC Arcade Volleyball , GPL Arcade Volleyball is even expanded as it includes extra features which the original game lacked. Game includes:

  • Network Volleyball client / server Game (up to 4 players)
  • 6 Game Themes which completely change the game look & feel to be modernistic

Here are few GAV screenshots of the different existing game Themes:

Screenshot GPL Arcade VolleyBall Yisus

GPL Arcade Volleyball Yisus theme gameplay GNU / Linux
Yisus GAV Theme gameplay screenshot

GPL Arcade Volleyball Unnamed Theme Screenshot

GPL Arcade Volleyball unnamed Gameplay Theme Debian
GAV – Unnamed Theme Gameplay

Screenshot GAV FABeach gameplay
GAV – FaBeach Theme Gameplay

GAV supports both Window and fullscreen modes. To enable Fullscreen mode, while inside the game use:

Extra -> Fullscreen (Yes)

Saving preferences is also something which I if I recall correctly the original game lacked. This is done by navigating to:

Extra -> Save Preferences

GAV is said to support Joystick in resemblance to the original DOS game, though I've never tested it with a joy.

One of the greatest GAV game (hacks) is the Inverted Theme. Selecting it inverts the order in the game, where the game player becomes the volleyball ball and the ball becomes the player ;)

GPL Arcade Volleyball Arcade Inverted Theme - remake of DOS Volleyball Arcade
GAV does not yet not have a Free / Open / Net BSD port as far as I currently see, anyways since the game is Free Software probably soon a port will be available for BSDs as well.
The default GAV game controls are a bit untraditional. By default the one player game starts you play Volleyball game player positioned on the left.

For left player the default control keys are:
 

  • z – move player left
  • c – move player right
  • left shift – jump

Right player controls are:
 

  • Left – left (arrow key)
  • right – right (arrow key)
  • jump – up cursor key

GAV supports also a shortcut key for switching between windowed and full screen game mode by pressing F10
Installing the game on Debian and Ubuntu Linuces is done with:

linux:~# apt-get --yes install gav

Unfortunately gav does not have a definition to be added to GNOME or KDE Applications menus, thus to start the game after installed one has to do it manually by typing either in gnome RUN (Alt+F2) or on command line:

linux:~$ gav

Happy playing ;)

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List and get rid of obsolete program core dump files and completely disable core files on FreeBSD

Tuesday, November 1st, 2011

My FreeBSD router has started running out of space, I looked for ways to clean up some space. So I remembered some programs are generating core files while they crash. Some of these files are really huge and ban be from 1Mb to > 1G.

I used find to first list all my produced core files starting from root directory (/) , like so:

find / -name core -exec du -hsc {} \;
....

Having a list of my core files with the respective core file size and after reviewing, I deleted one by one the cores which were there just taking up space.
It's a wise idea that core dumps file generation on program crash is completely disabled, however I forgot to disable cores, so I had plenty of the cores – (crash files which are handy for debug purposes and fixing the bug that caused the crash).

Further on I used an /etc/rc.conf dumpdev=NO , variable which instructs the kernel to not generate core files on program crash:

freebsd# echo 'dumpdev=NO' >> /etc/rc.conf

Next, to make dumpdev=NO , take affect I rebooted the server:

freebsd# shutdown -r now
...

There is a way to instruct every server running daemon to know about the newly set dumpdev=NO by restarting each of the services with their init scripts individually, but I was too lazy to do that.

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How to convert any internet Webpage to PDF from command line on GNU/Linux

Friday, September 30th, 2011

Linux webpage html to pdf command line convertor wkhtmltopdf

If you're looking for a command line utility to generate PDF file out of any webpage located online you are looking for Wkhtmltopdf
The conversion of webpages to PDF by the tool is done using Apple's Webkit open source render.
wkhtmltopdf is something very useful for web developers, as some webpages has a requirement to produce dynamically pdfs from a remote website locations.
wkhtmltopdf is shipped with Debian Squeeze 6 and latest Ubuntu Linux versions and still not entered in Fedora and CentOS repositories.

To use wkhtmltopdf on Debian / Ubuntu distros install it via apt;

linux:~# apt-get install wkhtmltodpf
...

Next to convert a webpage of choice use cmd:

linux:~$ wkhtmltopdf www.pc-freak.net pc-freak.net_website.pdf
Loading page (1/2)
Printing pages (2/2)
Done

If the web page to be snapshotted in long few pages a few pages PDF will be generated by wkhtmltopdf
wkhtmltopdf also supports to create the website snapshot with a specified orientation Landscape / Portrait

-O Portrait options to it, like so:

linux:~$ wkhtmltopdf -O Portrait www.pc-freak.net pc-freak.net_website.pdf

wkhtmltopdf has many useful options, here are some of them:
 

  • Javascript disabling – Disable support for javascript for a website
  • Grayscale pdf generation – Generates PDf in Grayscale
  • Low quality pdf generation – Useful to shrink the output size of generated pdf size
  • Set PDF page size – (A4, Letter etc.)
  • Add zoom to the generated pdf content
  • Support for password HTTP authentication
  • Support to use the tool over a proxy
  • Generation of Table of Content based on titles (only in static version)
  • Adding of Header and Footers (only in static version)

To generate an A4 page with wkhtmltopdf:

wkhtmltopdf -s A4 www.pc-freak.net/blog/ pc-freak.net_blog.pdf

wkhtmltopdf looks promising but seems a bit buggy still, here is what happened when I tried to create a pdf without setting an A4 page formatting:

linux:$ wkhtmltopdf www.pc-freak.net/blog/ pc-freak.net_blog.pdf
Loading page (1/2)
OpenOffice path before fixup is '/usr/lib/openoffice' ] 71%
OpenOffice path is '/usr/lib/openoffice'
OpenOffice path before fixup is '/usr/lib/openoffice'
OpenOffice path is '/usr/lib/openoffice'
** (:12057): DEBUG: NP_Initialize
** (:12057): DEBUG: NP_Initialize succeeded
** (:12057): DEBUG: NP_Initialize
** (:12057): DEBUG: NP_Initialize succeeded
** (:12057): DEBUG: NP_Initialize
** (:12057): DEBUG: NP_Initialize succeeded
** (:12057): DEBUG: NP_Initialize
** (:12057): DEBUG: NP_Initialize succeeded
Printing pages (2/2)
Done
Printing pages (2/2)
Segmentation fault

Debian and Ubuntu version of wkhtmltopdf does not support TOC generation and Adding headers and footers, to support it one has to download and install the static version of wkhtmltopdf
Using the static version of the tool is also the only option for anyone on Fedora or any other RPM based Linux distro.

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How to fix “Could not verify this certificate for unknown reasons” SSL certificate lighttpd troubles

Tuesday, June 28th, 2011

Firefox SSL Pro could not verify for uknown reasons solve error

I’ve been issuing new wildcard multiple SSL certificate to renew an expiring ones. After I completed the new certificate setup manually on the server (a CentOS 5.5 Final running SoluSVM Pro – Virtual Private Manager), I launched Firefox to give a try if the certificate is properly configured.

Instead of my expectations that the browser would just accept the certificate without spitting any error messages and all will be fine, insetad I got error with the just installed certificate and thus the browser failed to report the SSL cert is properly authenticated.

The company used to issue the SSL certificate is GlobeSSL – http://globessl.com , it was quite “hassle”, with the tech support as the first certficate generated by globessl was generation based on SSL key file with 4096 key encryption.

As the first issued Authenticated certificate generated by GlobeSSL was not good further on about a week time was necessery to completethe required certificate reissuing ….

It wasn’t just GlobeSSL’s failure, as there were some spam filters on my side that was preventing some of GlobeSSL emails to enter normally, however what was partially their fault as they haven’t made their notification and confirmation emails to pass by a mid-level strong anti-spam filter…

Anyways my overall experience with GlobeSSL certificate reissue and especially their technical support is terrible.
To make a parallel, issuing certificates with GoDaddy is a way more easier and straight forward.

Now let me come back to the main certificate error I got in Firefox …

A bit of further investigation with the cert failure, has led me to the error message which tracked back to the newly installed SSL certificate issues.
In order to find the exact cause of the SSL certificate failure in Firefox I followed to the menus:

Tools -> Page Info -> Security -> View Certificate

Doing so in the General browser tab, there was the following error:

Could not verify this certificate for unknown reasons

The information on Could not verify this certificate for unknown reasons on the internet was very mixed and many people online suggested many possible causes of the issue, so I was about to loose myself.

Everything with the certificate seemed to be configured just fine in lighttpd, all the GlobeSSL issued .cer and .key file as well as the ca bundle were configured to be read used in lighttpd in it’s configuration file:
/etc/lighttpd/lighttpd.conf

Here is a section taken from lighttpd.conf file which did the SSL certificate cert and key file configuration:

$SERVER["socket"] == "0.0.0.0:443" {
ssl.engine = "enable"
ssl.pemfile = "/etc/lighttpd/ssl/wildcard.mydomain.bundle"
}

The file /etc/lighttpd/ssl/wildcard.mydomain.bundle was containing the content of both the .key (generated on my server with openssl) and the .cer file (issued by GlobeSSL) as well as the CA bundle (by GlobeSSL).

Even though all seemed to be configured well the SSL error Could not verify this certificate for unknown reasons was still present in the browser.

GlobeSSL tech support suggested that I try their Web key matcher interfacehttps://confirm.globessl.com/key-matcher.html to verify that everything is fine with my certificate and the cert key. Thanks to this interface I figured out all seemed to be fine with the issued certificate itself and something else should be causing the SSL oddities.
I was further referred by GlobeSSL tech support for another web interface to debug errors with newly installed SSL certificates.
These interface is called Verify and Validate Installed SSL Certificate and is found here

Even though this SSL domain installation error report and debug tool did some helpful suggestions, it wasn’t it that helped me solve the issues.

What helped was First the suggestion made by one of the many tech support guy in GlobeSSL who suggested something is wrong with the CA Bundle and on a first place the documentation on SolusVM’s wiki – http://wiki.solusvm.com/index.php/Installing_an_SSL_Certificate .
Cccording to SolusVM’s documentation lighttpd.conf‘s file had to have one extra line pointing to a seperate file containing the issued CA bundle (which is a combined version of the issued SSL authority company SSL key and certificate).
The line I was missing in lighttpd.conf (described in dox), looked like so:

ssl.ca-file = “/usr/local/solusvm/ssl/gd_bundle.crt”

Thus to include the directive I changed my previous lighttpd.conf to look like so:

$SERVER["socket"] == "0.0.0.0:443" {
ssl.engine = "enable"
ssl.pemfile = "/etc/lighttpd/ssl/wildcard.mydomain.bundle"
ssl.ca-file = "/etc/lighttpd/ssl/server.bundle.crt"
}

Where server.bundle.crt contains an exact paste from the certificate (CA Bundle) mailed by GlobeSSL.

There was a couple of other ports on which an SSL was configured so I had to include these configuration directive everywhere in my conf I had anything related to SSL.

Finally to make the new settings take place I did a lighttpd server restart.

[root@centos ssl]# /etc/init.d/lighttpd restart
Stopping lighttpd: [ OK ]
Starting lighttpd: [ OK ]

After lighttpd reinitiated the error was gone! Cheers ! ;)

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Install grsecurity kernel security from binary package (without kernel recompile) on Debian and Ubuntu

Monday, July 26th, 2010

GRsecurity is since long time known that it is a next generation armouring agains 0 day local kernel exploits as well as variousof other cracker attacks.
Grsecurity is an innovative approach to security utilizing a multi-layered detection, prevention, and containment model. It is licensed under the GNU GPL.
GRSecurity is linux kernel patch which has to be applied to the kernel before compile time. However we’ve been lucky and somebody has taken the time and care to prepare linux image binary deb packages for Debian and Ubuntu .

Some of the key grsecurity features are :

  • An intelligent and robust Role-Based Access Control (RBAC) system that can generate least privilege policies for your entire system with no configuration
  • Change root (chroot) hardening
  • /tmp race prevention
  • Prevention of arbitrary code execution, regardless of the technique used (stack smashing, heap corruption, etc)
  • Prevention of arbitrary code execution in the kernel
  • Reduction of the risk of sensitive information being leaked by arbitrary-read kernel bugs
  • A restriction that allows a user to only view his/her processes
  • Security alerts and audits that contain the IP address of the person causing the alert

To install from the http://debian.cr0.org/ grsecurity patched kernel image repository use the following steps:

1. Include in your /etc/apt/sources.list

deb http://ubuntu.cr0.org/repo/ kernel-security/
deb http://debian.cr0.org/repo/ kernel-security/

Directly from the bash command line execute:

debian:~# echo "deb http://ubuntu.cr0.org/repo/ kernel-security/" >> /etc/apt/sources.list
debian:~# echo "deb http://debian.cr0.org/repo/ kernel-security/" >> /etc/apt/sources.list

2. Add the debian.cr0.org repository gpg key to the trusted repositories key ring

Download the repository’s gpg key , check it (it has been signed with the repository owner GPG key )

Thence from to include the gpg key to the trusted repos key issue:

debian:~# apt-key add kernel-security.asc

3. Install the linux-image-grsec package itself

Currently to install on my x86_amd64 Debian Squeeze/Sid and possibly on Debian Lenny I’ve issued:


debian:~# apt-get update
debian:~# apt-get install linux-image-2.6.32.15-1-grsec

Now simply restarting your system and choosing the Linux kernel patched with the GRsecurity kernel patch from Grub should enable you to start using the grsecurity patched kernel.
Though this tutorial is targetting Debian it’s very likely that the grsecurity hardened kernel installation on Debian will be analogous.

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Howto install GeoTrust RapidSSL certificate on Debian Lenny 5.0

Thursday, March 25th, 2010

I faced the task of generating official Validated SSL Certificates by in mydaily duties as a System Administrator at cadiaholding.com . Though generating self-signedSSL certificate is comparatively easy task. It was a pain in the ass setting Apache version 2.2.9-10+lenny6to correctly serve pages through https:// protocol over openssl version 0.9.8g-15+lenny6.I'll try to go through the whole process of Generating the certificate in order to help some other Debianusers out there to face less setbacks in such a simple task as installing a Trusted SSL Certificate issued(bought) by RapidSSL. Even though this article will mostly deal with SSL certificate issued by RapidSSL,it should be not a problem to apply this methodogy with Verisign or some of the other Geotrust issuedSecure Socket Layer certificates.
In generating the Validated certficate I used enom which is a domain name,ssl certificates, email and hosting company whole-saler.
Fron emon's website after logging in and using the web interface, there are two major things required to fill inin order to issue your Trusted SSL certificate.

1. Fill in in a form a CSR file, this is usually generated on the Linux server using the openssl.
To issue the CSR file required by Enom use the following commands:

a. First we generate an DES3 RSA encrypted key which we will use next to generate the opeensl CSR file required by ENOM.
debian:~# /usr/bin/openssl genrsa -des3 -out www.domain.com.key 2048
Enter pass phrase for www.domain.com.key:

You'll be required to fill in a pass-phrase that will be later be required to fill in before Apache servers starts or restarts,so make sure you fill something you either remember or you keep the password stored in a file.
You have to change also the www.domain.com.key in accordance with your domain name.
Now as we already have a proper generated DES3 RSA key afterwards it's necessery to generate the CSR file with the openssl command line frontend.
So here is how:

debian:~# /usr/bin/openssl req -new -key /home/hipo/www.domain.com.key -out /home/hipo/www.domain.com.csr

Again in the above example change all the paths and file names as you wish.
It's necessery that the end user fill in a number of questions related to the Certificate Signing Request.
Herein I'll list what kind of prompts will emerge after executing the above command:

Enter pass phrase for /home/hipo/www.domain.com.key:
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:
State or Province Name (full name) [Some-State]:
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (eg, YOUR name) []:
Email Address []:
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

Note that you'll hav eto fill in the pass phrase previously entered during the generation of the www.domain.com.key file.
In case if you'd like to read more thoroughly on the subject of howto create a Certificate Signing Request or (CSR) as we called it on multiple times, you can read About Certificate Signing Request (CSR) Generation Instructions – Apache SSL more in depth here

2. Hopefully following the above instructions you'll now have a file named www.domain.csrJust open the www.domain.scr and copy paste it's content to the ENOM website CSR * webform.3. Further on select your Webserver type on Enom's website:In our case we have to select Apache + ApacheSSL

4. What follows next is filling in your company contact information This is also required for proper certificate generation, you have to think twice before you fill in this data, take a note this can't be changed later on without issuing a brand SSL new certificate.

Apart from the 3 major above requirements to fill in Enom there are some few more radio buttons to use to make some selections according to your personal preferences, however I won't take time to dig in that and I'll leave this to you.
After all the above is fulfilled you'll have to submit your certificate details and choose an email address to which you will receive in a minute a RapidSSL Certificate Request Confirmation
Following a link from the email, will show you some basic information about the certificate about to be generated. That's your final chance to cancel the issued Trusted Certificated.
If you're absolutely sure the information about to enter the certificate is correct then you'll have to follow a link and approve the certificate.

You'll be informed that you'll receive your certificate either through Certifier website (e.g. Enom's website) or via another email.
I thought it's more probable I receive it via email but anyways I was wrong. More thank 4 hours has passed since the certificate was issued and is available via Enom's interface but I haven't received nothing on my mail.
Therefore my friendly advice is to check about your brand new shiny Trusted Certificate on Emom's website. I had mine ready in about 10 minutes after the CSR was issued.

Assuming that you've succesfully obtained the SSL Trusted certificate from RapidSSL what follows is setting up the certificate.
Initially I tried using documentation from RapidSSL website called Installing your SSL Certificate / Web Server Certificate / Secure Server Certificate from RapidSSL.com
I tried to configure one of my Virtualhost as shown in their example inserting in my /etc/apache/sites-available/www.domain.com file, few directives within the VirtualHost something like the shown below

SSLEngine on
# domain.com.crt cointains the Trusted SSL certificate generated and obtained by you from RapidSSL
SSLCertificateFile /etc/apache2/ssl/www.domain.com.crt
# www.domain.com.key contains the file used to generate the CSR file as described earlier in this post
SSLCertificateKeyFile /etc/apache2/ssl/www.domain.com.key

It is also possible insetad of using the SSLCertificateFile and SSLCertificateKeyFile directvies directives in Apache config to use:

 

Another alternative is to use

SSLCertificateFile /etc/ssl/certs/your-domain-name.crt
SSLCertificateKeyFile /etc/ssl/certs/your-domain-name.key
SSLCACertificateFile /etc/ssl/certs/gd_bundle.crt

The key file is the one generated earlier on the server and handed to the SSL regisrar, the files:

your-domain-name.crt and gd_bundle.crt files are provided by RapidSSL or from whatever SSL registrater the SSL was purchased.

After trying the above configuration and restarting apache with:

/etc/init.d/apache2 restart

Apache failed to start, it might be helpful to somebody out there the error I had in my apache error.log:
The error.log red the following:

[warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)

After some 30 minutes or an hour of Googling on the error I came to the conclusion that the error is caused, becauseApache is supposed to work with .PEM files instead of the classical .CRT and .KEY files asnormally approached in most of the other Unix operating systems.

It took me a bit more of reading on the internet to find out that actually the .pem files so widely adopted in Debian simply contain both the www.domain.com.key file and the www.domain.com.crt key simply pasted one after another, this I also observed from the default Apache self-signed certificate that I believe comes with debian /etc/apache2/ssl/apache.pem .
So I copied both the content of my www.domain.com.key and www.domain.com.crt and store it in one file:
/etc/apache2/ssl/www.domain.com.pem

Also the following configuration:
SSLEngine on
SSLCertificateFile /etc/apache2/ssl/www.domain.com.pem

had to go in your
/etc/apache2/sites-enabled/www.domain.com

Last thing that's left is to restart your Apache;

/etc/init.d/apache2 restart

Apache will prompt you for your certificate password entered by you during the www.domain.com.key generation. Type your password and with a bit of luck and hopefully with God's help you'll be having a Trusted Certificate on your webserver.

Last step is to check if the certificate is okay accessing your domain https://www.domain.com.

Well this is the end of the article, hope you enjoy.If you do please leave your comments, any corrections are also welcomed :)

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