M d Y

List, with pointers, Data Structure


Today I will introduce you to a list using pointers. This list doesn't have limit of elements (if you have infinite memory). Again the enunciation is too big, so take the file, read it and learn.

Stack with pointers implementation


PS: You can see the enunciation in portuguese and then use google translate to translate it

M d Y

Damn Small Linux, VirtualBox 2.2, Java


A week ago I was thinking about banks autentications, here in Brazil, you have to register your computer to get access to the bank site with your computer. Do this every time you format your hard disk is sux, so i thought, why don't use a virtual machine with a Damn Small linux and use it to access? It's a good idea.

I created my virtual machine with virtualbox and downloaded the last version of Damn Small Linux. I started the virtualmachine and i saw it was running from cd. Searching around the internet i discovered it is dedicated to live-cd but you can install it if you want to. In portuguese version I translated this article about how to install damn small linux but in english i don't have to.

So this is just a tip, if you have to register your computer to do some things, why don't you install a Damn small linux and use it for this? Other advantage is that you can take it with you, and linux don't have virus so you don't have to worry about this kind of security

If you want to install Java to firefox follow this article.

If your mouse don't work use "xsetup.sh" and choose a mouse that isn't USB. It works for me, now i have my USB mouse working. (I think it's something about Virtualmachin)


M d Y

Stack, using pointer, Data Structure.

This is a implementation of a Stack using pointers. The basic thing is the structure of tPilha is

constant MAXPILHA = 100;
tipo tPilha {
inteiro dados[MAXPILHA];
inteiro *topo;

Where *topo is a pointer to the first element in the stack. When you`re going to add a new one you verify if the stack is full, if it ins`t you put the data in a position in the stack and change the *topo. When removing, you decrement one in pointer *topo. Then it will reference the element that was there before.

(I had an enunciation but it was too big to translate)

stack with pointers implementation!


PS: You can see the enunciation in portuguese and then use google translate to translate it

M d Y

Netbeans 6.5.1, Line-spacing


I was using NetBeans in Ubuntu 9.04 when i started a new project and I realized that the line-spacing is so fucking bigger. To fix this you have to do this:

Edit the file "org-netbeans-modules-editor-settings-CustomPreferences.xml"

$ pico org-netbeans-modules-editor-settings-CustomPreferences.xml

This file will be in:


If the file and the directory exists just add the following lines:

<entry javaType="java.lang.Float" name="line-height-correction"

If don't you have to create the directory "Preferences":
$ mkdir Preferences
(In /home/user/.netbeans/6.5/config/Editors)

$ cd Preferences

And create the file:

$ pico org-netbeans-modules-editor-settings-CustomPreferences.xml

Add the following lines:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE editor-preferences PUBLIC "-//NetBeans//DTD Editor Preferences 1.0//EN" "http://www.netbeans.org/dtds/EditorPreferences-1_0.dtd">
<entry javaType="java.lang.String" name="code-template-expand-key" xml:space="preserve">
<entry javaType="java.lang.Float" name="line-height-correction" xml:space="preserve">

Save, restart netbeans and enjoy it. ;)

Good Night,

Portuguese Version


M d Y

Ubuntu 9.04, 64 Bits with Java.


I was trying to access my back account but I could not due to problems with the java. Talking with a friend, he told me what i have to install to get it working. If you want to use Java in Ubuntu 64bits you have to use "sun-java-plugin". To install it use this command:

sudo apt-get install sun-java6-plugin

See you,

PS: Forgive me for publishing just a little. I was traveling and now I have some tests in university.

M d Y

Ubuntu 9.04, reducing your boot time.

Hey, searching around the internet, i find some ways to decrease the boot time. All of them were for older versions, tham i decided to try it in new Ubuntu 9.04 (Jaunty Jackalope) and i get 22seconds boot time.

I used the bum (sudo apt-get install bum) to remove some things that i don't use.
This thins are:
acpid - Controls energy/buttons in pc/Laptop. If you don't use notebook or a keyboard with hotkeys you can remove it.
acpi-support - Like above.
hotkey-setup - Similar above.
anacron - This system runs processes periodically. You could remove it, and use cron.
atd - Like cron, Task Scheduler.
bluetooth - Bluetooth support
usplash - Without this, you don't see a beautifull loading screen when booting.
dns-clean - Used by dial-up connections.
pppd-dns - Used by dial-up connections.
saned - A lib for scanners.

Remember, i removed this things, like bluetooth and acpid because i don't use it. You shouldn't remove it, if you use. You must choose what item to remove according to your system.

$ sudo pico /boot/grub/menu.lst
and remove splash.

kernel /boot/vmlinuz-2.6.28-11-generic root=UUID=5be10a48-2c12-4165-8957-81c7a15274e5 ro quie splash
kernel /boot/vmlinuz-2.6.28-11-generic root=UUID=5be10a48-2c12-4165-8957-81c7a15274e5 ro quie

Reboot the system and executed the profiler. Press "e" in grub to edit, add to line that starts with "kernel" the word profile (add it in the end). Press "B" to boot. Wait a while, your boot is going to be slow. After this, reboot and see your boot time in bootchart.

If you want you can use Concurrent boot. To use it you have to edit /etc/init.d/rc
$sudo pico /etc/init.d/rc

And change

Save and restart. Verify your boot time and decide if you want to use it or not. (Probabily if you don't change boot order in rcX.d, You will not see difference.)

Usei o sudo bum (apt-get install bum) para remover algumas coisas que eu não usava.
As coisas removidas foram as seguintes:
acpid - Serve para gerenciar a energia/controles do pc/laptop. Se você não usa um notebook ou teclado com teclas te atalho pode remover.
acpi-support - Para notebooks. Como o de cima.
hotkey-setup - Semelhante ao anterior.
anacron - Este sistema roda processos periodicamente. Você pode remove-lo e colocar serviços criticos para cron
atd - Como o cron, esse também é um agendador de tarefas.
bluetooth - Suporte a Bluetooth
usplash - Remove a tela bonitinha de loading, aparecendo um monte de mensagens na tela. (remover splash da grub tbm. Abaixo)
dns-clean - Utilizado para conexões dial-up.
pppd-dns - Utilizado para conexões dial-up.
saned - Biblioteca para scanners.

Lembrando que removi pois não utilizava certos dispositivos, como bluetooth, agendador de tarefas e notebook. Voce deve ver se remove ou não de acordo com seu sistema.

For now just this, but when i have time I want to rebuild my kernel and see the diferences. Stay calm, i will keep you informed.

Matheus Bratfisch


M d Y

List, Data Structure

Good afternoon,

Like I said before I'm having Data Structure class. And today I will introduce you the List concept. A linear data structure. There is similar data structures like linked list, double linked list. The stack and the queue are special implementations of lists. The list can receive elements in any position, remove elements from any position, remove a specified element, add in order and others.

The professor told us to solve this:

1. Create the data type tLista in a headerfile
2. This list must be a list of elements of tAgenda
3. The type tAgenda is a type that represents a name (30 chars) and a telephone number
4. Create a function maior(a,b) that compare the name of 2 entries
5. Implement all the functions
6. Create a program that have a menu to use all functions and the specified search must use the name.
7. The program should be able to show the list in alphabetic order

List implementation.


M d Y

Ubuntu, VirtualBox 2.2 and USB


Now, with this new version of ubuntu, i will post alot about it while I'm trying configurations. I don't want to teach how to install VirtualBox 2.2, because it's a package .deb and is so easy to install it (Download Sun VirtualBox). In this post I want to remember that we should select the option "Enable IO APIC" in "Settings - General - Advanced". (My version of WinXp doesn't work without it). So if you system is not booting, verify this option. Now let's go to enable USB in your Virtual machine.

You have to install "Guest Additions", use the menu "Devices - Install Guest Additions". (Don't forget to mount it on your cd in virtualbox)

After you install it go to console:

$ grep vbox /etc/group
The result is something similar to this: vboxusers:x:gid:user

(If your user is not there, add it "System - Administration - Users and groups")

Edit the file "mountkernfs.sh":
$ sudo pico /etc/init.d/mountkernfs.sh

Go to the end of do_start(), and before the } add this line:
domount usbfs "" /proc/bus/usb usbdevfs -onoexec,nosuid,nodev,devgid=GID,devmode=644

(Replace the GID with your GID)

Save the file, reboot the computer and use your usb in your virtualmachine.

The site that make me try this way is http://www.davidgrant.ca/virtualbox_usb_windows_xp_guest_ubuntu_hardy. This website don't says it works on Ubuntu 9.04 (Jaunty), so i tried and it worked.

I hope this is useful,

PS: You have to select the device you want to use in virtual machine in "Device - USB DEVICES"

M d Y

Ubuntu 9.04, bootChart.


I decided to stay in computer a little more, and have a test with this fresh installation of Ubuntu 9.04. Some people say that the boot would be faster in this new version, so I decided to verify this. I remember in my last instalation (Ubuntu 8.10) with fresh install I got 31 seconds on boot, after some modifications it reduces to 21 seconds. In this version, as promised the boot time decreased. I got 26 seconds. When I have some time i'm going to try to do some optimizations and decrease it more.

To verify the time I used Bootchart. You can get it using:

$ sudo apt-get install bootchart

Or you can go to menu "System -> Administradion -> Synaptic Package Manager" and search for it.

BootChart Image, BootChart logs.

Good night,

M d Y

Ubuntu 9.04, up and running.

Hello guys,

In the last thursday the Ubuntu 9.04 was released. I decided to try the 64 bits version, I didn`t used EXT4 (but I thought alot). The installation was complete in 20 minutes (fast, right?). I like the design of the new login screen. I didn`t have any big problem until now, it have a closed nvidia driver and flash. Tomorrow I intend to try eclipse, java, etc.

The Java version is:

x-warrior@x-warrior-desktop:~$ java -version
java version "1.6.0_0"
OpenJDK Runtime Environment (IcedTea6 1.4.1) (6b14-1.4.1-0ubuntu7)
OpenJDK 64-Bit Server VM (build 14.0-b08, mixed mode)

Matheus Bratfisch