Tuesday, May 24, 2011

Partitions - Type and Sizes For Linux

- it's best to put /usr, /var, /tmp, and /home each on their own partitions separate from the / partition.
- /usr/local partition if you plan to install many programs that are not part of the Debian distribution.

- Putting /tmp on its own partition is a good idea.
(Beware that the default path for Brasero to create iso file is /tmp)
(All files in /tmp will be purge every time debian restart)

- If your machine will be a mail server, you might need to make /var/mail a separate partition.
A mail server getting spammed with e-mail can easily fill a partition.
If you made /var/mail a separate partition on the mail server, most of the system will remain working even if you get spammed.
- postgres data files?
- apt cache

contain static data
The usage space of /usr in my desktop is ~3G.

Arch: 32MB (https://wiki.archlinux.org/index.php/Beginners%27_Guide)
Ubuntu: About 500 MB is recommended. (http://www.linuxbsdos.com/2010/10/12/ubuntu-10-10-manual-disk-partitioning-guide/)
Redhat: Minimum size = 250 MB (http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/s2-diskpartrecommend-x86.html)
Debian: the boot partition should be ext2 or ext3. (http://forums.citrix.com/thread.jspa?threadID=284981)

- By putting swap on a separate partition, Linux can make much more efficient use of it.
It is possible to force Linux to use a regular file as swap, but it is not recommended.

On 32-bit architectures (i386, m68k, 32-bit SPARC, and PowerPC), the maximum size of a swap partition is 2GB.Ref: https://help.ubuntu.com/11.04/installation-guide/amd64/apcs03.html

Swap should equal 2x physical RAM for up to 2 GB of physical RAM, and then an additional 1x physical RAM for any amount above 2 GB, but never less than 32 MB.

So, if:

M = Amount of RAM in GB, and S = Amount of swap in GB, then

If M < 2
    S = M *2
    S = M + 2

Using this formula, a system with 2 GB of physical RAM would have 4 GB of swap,
while one with 3 GB of physical RAM would have 5 GB of swap.
Creating a large swap space partition can be especially helpful if you plan to upgrade your RAM at a later time.

For systems with really large amounts of RAM (more than 32 GB) you can likely get away with a smaller swap partition (around 1x, or less, of physical RAM).
Ref: http://www.centos.org/docs/5/html/Installation_Guide-en-US/s1-diskpartitioning-s390.html

File Systems (Partition Type)
- if your partition is larger than around 6GB, choose ext3 as your partition type.
- Ext2 partitions need periodic file system integrity checking, and this can cause delays during booting when the partition is large.

Fedora 14 >
ext4 for /boot, / is mandatory. (shown during installation)

https://ext4.wiki.kernel.org/index.php/Frequently_Asked_Questions >> Break 32000 subdirectory limit

As of 27-8-2011, VirtualBox still have some problems on ext4.

ubuntu packages for development

HTML Editor
sudo apt-get -y install quanta
# Quanta Plus is a web development tool for the KDE software users.

sudo apt-get -y install kcolorchooser kruler

cannot distribute the intellij idea files since that is not allowed by it's license, so uploading it to a public PPA would put you in breach of the license.
just download the tarball from the homepage, unpack it in your home dir, edit the start script idea.sh to export the JDK_HOME path, and you're good to go.
tar xfz idea-7.0.1.tar.gz ./usr/lib/
/bin/sh -c "export JDK_HOME=/usr/lib/jvm/java-6-sun&&/data/idea-IC-103.255/bin/idea.sh"

Ref: http://ubuntuforums.org/showthread.php?t=1705161
Thanks: http://blog.jeroenreijn.com/2010/01/creating-intellij-launcher-on-ubuntu.html


sudo apt-get install openssh-server

ubuntu home-user packages natty narwhal 11.04

my favorite home-user packages on ubuntu

Thai fonts
sudo apt-get -y install ttf-dejavu ttf-mscorefonts-installer otf-thai-tlwg ttf-thai-arundina ttf-thai-tlwg
> Thai fonts in OpenType format
> Font Loma, ...

sudo add-apt-repository ppa:ferramroberto/java
sudo apt-get update
sudo apt-get install sun-java6-jdk sun-java6-plugin sun-java6-fonts

sudo apt-get -y install firefox flashplugin-installer
# Firefox is a GTK application


sudo apt-get -y install chromium-browser


sudo apt-get -y install pidgin

sudo apt-get -y install geeqie
# Geeqie is a lightweight Gtk+ based image viewer for Unix like operating systems.

sudo apt-get -y install kipi-plugins

sudo apt-get -y install kolourpaint4
sudo apt-get -y install kcolorchooser kruler

sudo apt-get -y install libreoffice-writer libreoffice-impress libreoffice-calc libreoffice-l10n-th
# Similar to OpenOffice.org, LibreOffice relies heavily on Java : http://www.linux-magazine.com/Online/Blogs/Productivity-Sauce/LibreOffice-OpenOffice.org-Liberated

Media player
sudo apt-get -y install vlc gstreamer gstreamer-plugins-good gstreamer-plugins-bad gstreamer-plugins-ugly


sudo apt-get -y install unrar zip unzip p7zip-full p7zip-rar rar

sudo apt-get -y install goldendict
# goldendict use Qt 4

# for creating custom dictionary
sudo apt-get -y install stardict-tools


Nautilus Elementary
สำหรับปรับแต่ง Nautilus ได้อย่างอิสระและสวยงามอีกด้วย

sudo apt-get -y install kde-service-menu-fuseiso kscreensaver kwrite

kim4: downlaod at http://kde-apps.org/content/show.php?content=11505
and read manual

Theme: http://opendesktop.org/content/show.php?content=76197

Performance tuning KDE

disable Strigi
System Settings -> Desktop Search
There are 2 components to Nepomuk.

The component that sucks up CPU and IO is the Strigi file indexing service.
This extracts metadata from files.

The second and more important component is the Nepomuk metadata service.
This is where the file indexer stores metadata, but also, applications using the nepomuk libraries can store arbitrary data.

If you disable all of Nepomuk, KMail will not be able to do email address completion from your address books,
or distribution lists, file rating and tagging will not work.

By disabling all of Nepomuk you save about 50MB for the virtuoso database backend but very little CPU and IO.
You can disable Strigi on its own if you don’t care about file search and indexing.


installing lubuntu 11.04 natty narwhal

The graphical installation system (Ubiquity) requires more RAM than Lubuntu needs to run.
you will also find this alternate installation method faster if you have less than 256MB RAM than using the standard install method.
Please be aware that your system may seem to 'hang' (stop) at about 90% (dpkg),
it has not; it just takes a little time (up to 90 minutes).
Ref: https://help.ubuntu.com/community/Lubuntu/Documentation/AlternateInstall


after installing
sudo apt-get autoremove

sudo apt-get update && sudo apt-get upgrade

sudo apt-get -y install zenity
# For im-switch (Input Method Switcher)

Note: LXDE (Lightweight X11 Desktop Environment) is based on GTK+

Language Support
1. Go to Preferences --> Language Support.
You will be asked to completely install language support, do so.
2. Click on the 'Install / Remove Languages' button to pull up the list of available languages
3. .....
Ref: https://help.ubuntu.com/community/Lubuntu/Documentation/LanguageSupport

Keyboard layout switcher
add this line
@setxkbmap -option grp:switch,grp:alt_shift_toggle,grp_led:scroll us,th
to /etc/xdg/lxsession/Lubuntu/autostart
Thanks: http://kobinter.blogspot.com/2011/05/lubuntu-1104.html

Autostart applications
There are two types:
1) autostarted applications go to menu -> preferences -> desktop session settings

2) Lubuntu and LXDE has some essential applications that will run everytime you start your system.
These kind of programs manage your powersettings for your laptop or netbook or draw icons on the desktop.
If you don't need these applications as you are using a desktop computer
or simply don't need desktop icons
you can disable those applications by editing the autostart script of the lubuntu session.
This file needs root rights to be modified and is located under /etc/xdg/lxsession/Lubuntu/autostart.
Ref: http://lubuntu.net/blog/lubuntu-screencast-extreme-memory-tuning

http://wiki.lxde.org/en/LXDE:Questions << FAQ (such as How do I change the hotkeys?)

The directory tree is not yet added to PCManFM itself. >> http://blog.lxde.org/?p=828

Lubuntu Control Center

Friday, May 20, 2011

Module Setting on Intellij for Google map on Android

เลือก Scope เป็น Provided

05-20 10:58:50.781: ERROR/AndroidRuntime(17761): FATAL EXCEPTION: main
java.lang.NoClassDefFoundError: com.package.ViewMap
at com.package.ListBridge.gotoViewMap(ListBridge.java:57)
at com.package.ListBridge.access$000(ListBridge.java:10)
at com.package.ListBridge$1.onClick(ListBridge.java:19)
at android.view.View.performClick(View.java:2408)
at android.view.View$PerformClick.run(View.java:8818)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:871)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalAccessError: Class ref in pre-verified class resolved to unexpected implementation
at dalvik.system.DexFile.defineClass(Native Method)
at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:209)
at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:203)
at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
... 14 more

Tuesday, May 10, 2011



The CFE file, which is the program that boots the router and is specific to your router,
the NVram which is the memory for settings
the kernel which is the firmware.
Installing programs on a router, known as firmware, are achieved by a method called flashing.
Brick = a device that cannot function in any capacity (such as a device with damaged firmware).
more at http://en.wikipedia.org/wiki/Brick_(electronics)

This is SUPER easy and REALLY important.

Some people share efc online
but your MAC address is stored in the CFE file
Ref: http://www.dd-wrt.com/phpBB2/viewtopic.php?t=51486

ระยะทางประมาณ 4-5 กม.

Do not raise your TX value
should fix signal issues with better antennas not power.
Many routers do much better with LOWER TX values,
around 40-50 especially those with the crappy internal antennas (linksys ashtrays).

ยิ่งปรับ tx power เยอะ, speed รับส่ง ยิ่งต่ำ

more about external antenna
(yagi, panel antenna, biquad dish antenna, gain, milliwats, dbi, dbd, etc.)
see http://www.dd-wrt.com/phpBB2/viewtopic.php?t=43810,

network analysis Software

Wi-Fi tools that help troubleshoot WLAN networks.



Compile kernel เอง