The myth of drop_caches

I will try to clarify the myth about drop_caches.
This along with other settings can be made in the folder: /proc/sys/vm/
First, the files in this directory can be used to tune the operation
of the virtual memory (VM) subsystem of the Linux kernel and also to
write out of dirty data to disk.
About drop_caches we can say that is only one of the options and not only make
causes the kernel to drop clean caches, and entries inodes from memory,
the result causing that memory to become free.
We have three basic options :

• to free pagecache: echo 1 > /proc/sys/vm/drop_caches
• to free dentries and inodes: echo 2 > /proc/sys/vm/drop_caches
• to free pagecache, dentries and inodes: echo 3 > /proc/sys/vm/drop_caches

Note that user should run sync first.
What happens then?
The answer is also simple and clear.
If you drop the cache than the CPU load goes up. This happens because the cache is gone.
Also, available RAM goes up because the cache is empty.
Logical, the performance will suffer because you are not taking advantage of the cache.
Then over time, the caches will fill and this is a good thing if you don't instruct Linux to drop the caches.

In reality, dropping caches has a little positive effect on performance, but in fact, it tends to have a negative effect in long-term.
I hope I have correctly understood and explained, so if you think it is not, I wait for your feedback.

Fighting Blender, NVIDIA and GNOME ...

Today I spent some time with Blender, NVIDIA and GNOME ...
Since I did pre-update and put Fedora 15, the system worked well until today.
Today I tried to relax a bit with Blender 3D, but ...

[free-tutorials@user ~]$blender
Info: Config directory with "startup.blend" file not found.
Segmentation fault (core dumped)

How to prevent uploading that file? Simply using:

[free-tutorials@user ~]$blender --factory-startup 
Segmentation fault (core dumped)

Obviously, I should try to debug:

[free-tutorials@user ~]$blender --factory-startup  -d
Blender 2.57 (sub 0)
Build: 2011-04-27 16:56:56 Linux:32bit Release
argv[0] = blender
argv[1] = --factory-startup
argv[2] = -d
read file 
  Version 256 sub 6 svn r36063

ordered
 OBCube
 OBLamp
 OBCamera
Segmentation fault (core dumped)

Simply don't want, it's something related to graphics card ...

[free-tutorials@user ~]$blender --factory-startup  -d -noglsl 
Blender 2.57 (sub 0)
Build: 2011-04-27 16:56:56 Linux:32bit Release
argv[0] = blender
argv[1] = --factory-startup
argv[2] = -d
argv[3] = -noglsl
read file 
  Version 256 sub 6 svn r36063

ordered
 OBCube
 OBLamp
 OBCamera
Segmentation fault (core dumped)

So the problem is not related to GLSL.
Then I tried to see what glxinfo says.

[free-tutorials@user ~]$glxinfo | grep Error
Error: glXCreateContext failed

I found this problem and I added to xorg.conf the following lines of code.

Section "Files"
ModulePath "/usr/lib/xorg/modules/extensions/nvidia"
ModulePath "/usr/lib/xorg/modules/drivers"
ModulePath "/usr/lib/xorg/modules"
EndSection 

I must admit that after restarting the computer, greeted me with the gnome interface and unprecedented special effects.
Then I waited ... and waited ... I fixed up with a simple line of code:

$  gsettings set org.gnome.desktop.session session-name 'gnome-fallback'

... written in Xfce terminal, because in gnome I have not succeeded.
Now I have the old gnome, slightly improved but it works flawlessly with Blender 3D...

News: "A tour of Eclipse Helios" by IBM

It's a pretty good and complete information about Helios ...
Article begins:

Helios is the simultaneous release of 39 Eclipse projects. In terms of statistics, the Helios release includes 33 million lines of code developed by about 500 Eclipse.org committers from 44 companies...

You can read here and you will be impressed by the new Helios.
The best part for Linux users is Linux tools.
As Andrew Overholt says in the same article:

"The Linux Tools project also aims to increase the amount of Eclipse technology available in Linux distributions. We are working towards this goal by providing a build harness of the Eclipse SDK that is easy to consume for Linux distributions and already have a number of distribution consumers."

I have not yet found the negative aspects from the Helios ...

What things should be fixed quickly ?

Here are some things that should be repaired.
There are minor things or less, but make life a misery. There are things that generate more questions and more errors on the Internet.
This is an epidemic of questions there just because they are not repaired.

1. Google must give the possibility to download video files updated...
2. Python modules gdata do not work for all versions... ( and many modules has the same problem)
3. Python module ftplib does not know about SFTP, just FTP
4. Too many compilers for C and C + + and lack of advanced tutorials for setting them, especially gcc on windows
5. Social networks Spam filling our mail.


I will try to update the list over time.
I'm sure there are more ...

The word "includ" generates error in gmail.

I accidentally discovered an error.
I sent feedback to Google, I hope to resolve quickly.
The problem is with the word "include" is a word used in the Romanian language and means "include".
Because of this, I can not send emails it contains, Gmail asking to "include file"

The discovery of an ancient ancestors linux ...

Who says penguins are weak?
Linux is a good system if it is used by smart people.
Since ancient times people are born with penguins.
It seems that dinosaurs could not survive, but the Penguins have managed well.
They became smaller but everyone loves them.
Whether they are small and fast as Gentoo, or slower ... we are glad that we have no windows open.
More info here.

Nokia SDK and MIDlet

Yesterday I played with the SDK from Nokia. Do you think that it's easy to create a MIDlet?
Finally, I managed to make an application "Hello World'.
Maybe I'll write a little tutorial in the near future when I'll know more about MIDlets and java.
Here is the resulting feedback.

Blender 3D and F14 killed by "Save as"

Although he reached the 2.55 beta, Fedora 14 is still struggling with version 2.49b.
Not bad if it goes, but here's one little problem
It's all well and good until the "Save as".
Then it breaks and you have just this reason:
Process /usr/bin/blender.bin was killed by signal 6 (SIGABRT)

Christmas - new decor script for your desktop .

Last year I made a python script to beautify your desktop on Christmas Day.
I wrote it here about this script.
I lost the script, but now  I wrote this script again.
The script is very simple and you can get it here.
Here's what makes this script:

gDEBugger - FREE or NOT ?

A very popular OpenGL debugger is now available for FREE?
On official site we saw:
Order
gDEBugger is not available for purchasing for the time being.
We plan to release a new and **FREE** gDEBugger version for Windows, Linux and Mac OS X. This version will be available for download by the end of 2010.
Please make sure to check our website for this version in the near future.
Until the free version will be released, please find below a temporary license file that will enable you to use the current gDEBugger version for free immediately.
Now is the end of 2010, but is not free.
What is gDEBugger
Named gDEBugger is an advanced OpenGL Debugger, Profiler and Graphic Memory Analyzer.
This 3D software saves you debugging time and helps you boost application performance.
We can download it from :here.
I searched my computer the lib libstdc++, see below :

# yum search libstdc++
Loaded plugins: langpacks, presto, refresh-packagekit
Adding en_US to language list
============================== Matched: libstdc++ ==============================
compat-libstdc++-296.i686 : Compatibility 2.96-RH standard C++ libraries
compat-libstdc++-33.i686 : Compatibility standard C++ libraries
libstdc++.i686 : GNU Standard C++ Library
libstdc++-devel.i686 : Header files and libraries for C++ development
libstdc++-docs.i686 : Documentation for the GNU standard C++ library
libstdc++-static.i686 : Static libraries for the GNU standard C++ library

The archive named gDEBugger57-i386-cpp3.tar.gz has 13Mb.
Then I use commands :

$gzip -dc gDEBugger57-i386-cpp3.tar.gz | tar xf -
$ cd gDEBugger57-i386-cpp3
$ su 
# yum install compat-libstdc++-33.i686 

The gDEBugger run well under fedora 14 , but is free only 7 days. See below:

Fakeroot and Yum

It seems that the yum and fakeroot do not get along too well.
I did not understand why ... Here is output:
yum search aaa
Loaded plugins: langpacks, presto, refresh-packagekit
Adding en_US to language list
Cannot open logfile /var/log/yum.log
Could not create lock at /var/run/yum.pid: [Errno 13] Permission denied: '/var/run/yum.pid'
Another app is currently holding the yum lock; waiting for it to exit...
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 258, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 104, in main
    show_lock_owner(e.pid, logger)
  File "/usr/share/yum-cli/utils.py", line 107, in show_lock_owner
    ps = get_process_info(pid)
  File "/usr/share/yum-cli/utils.py", line 62, in get_process_info
    if (not os.path.exists("/proc/%d/status" % pid) or
TypeError: %d format: a number is required, not str 
And I have nothing on, like rpm, yum or gpk-prefs...

Fedora 14 and NVIDIA FX5200

Today I set video driver on Fedora 14.
I have an FX5200 and I use akmod to make this working.
First when I install akmod with :

yum install kmod-nvidia-173xx-2.6.35.6-48.fc14.i686.PAE.i686

I have some errors:

$ glxinfo | grep direct
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Error: couldn't find RGB GLX visual or fbconfig
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".

But i solve and Savage XR working well :

Fedora 14 versus 3D software .

In the next few days ago I decided to try software 3d with Fedora 14.
I am disappointed again. I was expecting some improvements in this area by the developers.
Especially because it is a difficult topic.
But let's see why I have this impression...
I have searched for packages that are required with this command:

# yum search "3d engine"
...
============================== Matched: 3d engine ==============================
irrlicht.i686 : A high performance realtime 3D engine
crystalspace.i686 : Crystal Space a free 3D engine
ember.i686 : 3D client for WorldForge
ogre.i686 : Object-Oriented Graphics Rendering Engine

Code:: Blocks does not work with Ogre 3D or Irrlicht 3D packages. Although I spent quite a long time. However, on Windows XP this combination worked well.
Ember game working hard. Maybe because my video card - FX5200, not really likes the new drivers.
Code:: Blocks is very stubborn. Ogre and Irrlicht Wizards of the Linux version of Code:: Blocks does not work at all.