sudo apt-get install linux-server linux-headers-server

It has been a while since I stopped writing, blogging and etc. Missing all these too much, so it’s time to restart and return with articles and publishing some work I’ve been researching and doing…

Stay tuned

That’s right… Just completed one month working at USA…

So far, so good… Let’s check if I’ll survive this cold here and of course,

the home sick…

Sempre me perguntei porque a Microsoft lançou o Windows Vista como um software estável, dado que a maioria dos usuários  sabem que ele ainda é BETA, senão ALPHA…
Porém, pesquisando inutilidades alteatórias na internet (a arte), descobri que Gil Brother, O Away de Petrópolis, foi um  dos desenvolvedores… Segue abaixo o trecho da Desciclopédia.

Gil Brother, também conhecido como Gil Brother Away* é um jrnalista, desenvolvedor do Windows Vista, comentarista, dançarino, traficante, leitor da Desciclopédia, criador da bossa nova,criador de cabrito, jogador de futebol, coyote (atravessador da fronteira EUA Tekilas), filósofo, comandante do PCC, ex-membro do cartel de Medelín, obstetra, jagunço, professor de gramática, ex-fuzileiro naval, bicheiro, neurologista, psicanalista junguiano, um grande advogado muito conceituado na ADEBRA (Adevogados do Brasil), assassino da Taís (gêmea má da novela), doleiro, pecuarista (criador de cabritos fortemente nervosos pra mamar lá em seu sítio) e também ex-governador do Rio de Janeiro. Conhecido por casos como de Luis Boça e Vó Lurdes, Gil Brother (tambem conhecido como Professor Gilmar) é MD PHD HD120GB e fundador do Artigo 121 combinado com 12!

Sem comentários, faz todo sentido!

Cara, podem falar o que quiser… Mas a tecnologia utilizada por empresas de Telecom é muito legal. Creio que os meus próximos livros técnicos serão sobre redes 3G e coisas do tipo…
Cade o meu professor de circuitos digitais e redes, Sr. Hamilton, nessas horas hein ? Esse é o cara.

scott/tiger

Almost every Oracle database has had an account called SCOTT with password TIGER. It is named after Bruce Scott (one of the original Oracle employees) and the password is the name of his daughter’s cat. This schema contains the EMP and DEPT tables used in innumerable demos. In recent versions of the database, this account is locked by default and must be unlocked with

SQL> ALTER USER SCOTT ACCOUNT UNLOCK;

Oracle XE inexplicably doesn’t have this classic account, but you can add the user yourself and fill it using the demobld script.

Later versions has an additional demo schema called HR with password HR. This schema contains many additional database objects to allow demonstration of newer database features.

The following links discuss the new sample schemas in more detail.

• Following SCOTT/TIGER

• Oracle’s Sample Schemas: Saying Goodbye to Scott
• Build oracle sqlplus demo table

To drop Scott you need to run the demodrop.sql script

Source: http://wiki.oracle.com/page/scott%2Ftiger

This is one is quick but very helpful

  ls -laR | wc -l

With that, you will count all files under the current and subdirectories.

Well, I heard (read to be honest) somewhere that ext4, the evolution of ext3 linux file system, is coming out from development to stable tree (Kernel 2.6.28). However, I was not so sure about the benefits and how this can improve my life and my performance in daily tasks using my 80gb HD laptop. Here is the features I found in my search:

• Large filesystem: It can support volumes with sizes up to 1 exabyte (1024 GB == 1 Tera. 1024 Tera == 1 Peta. 1024 Peta == 1 Exa). Since Linux kernel version 2.6.25, it also supports files as large as the file system.
• Backward and forward compatibility: It has backward compatible with ext3, making it possible to mount an ext3 filesystem as ext4 and vice-versa, but the ext4 to ext3 is only possible if extents is not enabled.
• Delayed allocation: With this feature, ext4 can delay block allocation as long as possible, improving performance and reducing fragmentation, since it will only allocate space with the real file size.
• Expand the subdirectory limit up to 64000: Shame on you Window$
• Faster file system checking: The data structures used in ext4 allows fsck to skip unused blocks of data, which will reduce the time fsck may spend.
• Undelete: It’s not yet implemented but this feature will also be supported and it’s very handy in many situations.
• Other fixes…

But the discussion here: is it really for you ? Do you need a filesystem with 1 exabyte limit ? Create more than 32,000 subdirectories ? I mean, of course that there are other performance improvements and they are very important and welcome, thanks. But I’m not so sure about experiment ext4 now, since I’m only with one machine and using it for work.   Maybe in few months or with the next Ubuntu release I’ll have it. At least,  I’m already aware of what I can expect about ext4.

For those who want’s to migrate from ext3 to ext4 now, I found this step-by-step article at IBM developerWorks and looks very helpful.

For those who needs to look at some huge log files (usually generated by Java servers such as weblogic, tomcat or jboss…) or needs to check thread dumps (stuck thread sucks) here goes a great tool: TDA (Thread Dump Analyzer).

In a JEE architecture we have a daily work with multi-thread environments. All applications (or most of them) needs to run in cluster and share the load between many machines, domains, work managers or threads.  In such scenarios, it’s important to identify which class made a thread stuck ? What’s going on in the JVM in the moment the application stops working and freeze.  In such situations, you can take a look at the thread dump. But what is a thread dump ? In few words: a textual dump of all active threads and monitors of Java apps running in a Virtual Machine.

Of course there are much more to say about thread dumps, but today I’m just posting about a tool that can helps working thread dumps and some server side logs… TDA! (not a sound)

Here are the new features listed from TDA home:

• Tool now is available as VisualVM plugin.
• Skip broken thread dumps.
• Custom Thread Categories.
• New Welcome Screen.
• Small Adjustments to support SAP JVM Dumps (slightly modified from SUN Dumps).
• Small Adjustments to support HP JVM DUmps (slightly modified from SUN Dumps).
• Icons of monitors with high contention now have a red background (issue 13).
• Multiple Selection of Threads (issue 11).
• Stack line count is now also set in long running thread result (issue 19).
• Read heap information from Sun JDK 1.6 Dumps and display them.
• Thread Dumps or logfiles can be pasted from clipboard (issue 20).
• Internationalisation (only english available so far, not finished yet).
• Extended Help, now uses javahelp

Click here to download.

More info: https://tda.dev.java.net/

ALDSP Version: 3.0.1
WLI Version: 9.2.2
OS: Ubuntu 8.0.4 (2.6.24-19-generic, x86_64)
Problem description: When you try to create a new DSPControl in a Process project (WLI), after the settings (remote context, ip, application name, etc…) you select which data service you want this control to call. After that, click on finish. I’ve just got an error message saying that Workshop try to create a directory called /tmpcontrolxsd1223392115385/classes/apache_schemaorg_xml. The directory name changes each time you click on finish.. But the point is, WHY ? WHY Workshop need to create that in the root directory ? Under / ? Come on… Doesn’t make sense and I didn’t find a way to setup that.
Dirt-quick workaround: Run workshop with sudo permission or give write permission on / to the user that you are running workhsop. I prefer the first one, but I’ll research about this bug and try to figure out another way to do that…