Showing posts from April, 2010

Reset the Linux Root User Password, If you forget the password

With Screen Shots:

Follow these steps to reset the password when using GRUB
1) Reboot the system, and when you are at the selection prompt, highlight the line of Enterprise Linux and press ' e ' from keyboard.

2) This will take you to another screen where you should select the entry that begins with ' kernel /boot/vmlinuz-2.6.18-164.el5 ro root=LABLE=/ rhgb quiet' and press ' e ' again.

3 ) Append ' single' to the end of that line (without the quotes). Make sure that there is a space between what's there and ' single ' and press enter. If your system requires you to enter your root password to log into single-user mode, then append init=/bin/bash after 'single'. Hit 'Enter' to save the changes.

4) Press 'b' to boot into Single User Mode.

5) Once the system finishes booting, you will be logged in as root. Use passwd and choose a new password for root.

6) Type reboot to reboot the system, and you can login with the new passwor…

Oracle's Free / Open Source Technologies


Oracle JDeveloper is a free integrated development environment (IDE) for building Web service-oriented applications using industry standards for Java, XML, SQL, and Web Services. It supports the complete development life cycle with integrated features for modeling, coding, debugging, testing, profiling, tuning, and deploying applications.

Oracle VM

Oracle VM is a free server virtualization platform that supports both Oracle and non-Oracle products. Many of Oracle's products are supported and certified for the Oracle VM platform. 

Oracle Enterprise Linux

Oracle is a major contributor to the Linux community. Oracle has made significant contribution in Linux such as its own Unbreakable Oracle Enterprise Linux (OEL).


It is a free and Open Source Integrated Development Environment (IDE). You can create professional Desktop / Enterprise / Web and Mobile Applications with Java, C/C++, PHP, JavaScript, Groovy, and Ruby using NetBeans.


Glassfish is a lightweight, flexi…

Monitoring DML Operations on the Tables

The Oracle feature Monitor, monitors the DML operations INSERT / UPDATE / DELETE and TRUNCATE on the tables. Table monitoring can be implemented on a table by executing the following statement:-
Once monitor option is enable for a table, all DML operations on it are register in a view ( sys.DBA_TAB_MODIFICATIONS) based on sys.mon_mods$ table. The DML counters from this view represent the number of DML operations since the last gather statistics.
The overhead on performance is not to be considerable since this mechanism work on memory and flush changes to DBA_TAB_MODOFICATIONS view periodically.

In 9i, tables should be implemented with monitoring by executing "alter table table_name monitoring", but in 10g monitor is enabled by default.

The advantage of this feature is when gathering statistics. Based on the dba_tab_modifications view we can gather statistics for only tables that have more than X% changes (compared to num_rows in user…

Wellcome to New Secure Operating System QUBES in Open Source world

The famous Polish beauty hacker Joanna Rutkowska recently released a new Open Source Operating System which is based on Xen, X Window System, and Linux. This new Open Source Linux Operating System, known as Qubes.
Qubes biggest advantage is safety. It makes full use of virtualization technology (based on the Secure Virtual Machine Xen), all user applications are run in AppVM (lightweight Linux-based Virtual Machine), the mutual isolation. The networking code uses the IOMMU / VT-d in a non-privileged virtual machine, in the privileged domain (dom0) there are no networking code. Many system-level components on the sand box in order to avoid affecting each other.
In addition, Qubes allow the user to define many of the security domain (with the lightweight virtual machine implementation), such as "personal", "work", "shopping", "bank" and so on, separated from each other. In addition, also supports replication between different security domains - pa…

PL/SQL Explicit Cursor with Examples

An explicit cursor is defined in the declaration section of the PL/SQL Block. It is created on a SELECT Statement which returns more than one row.

There are four steps in using an Explicit Cursor.
1)DECLARE the cursor in the declaration section. 2)OPEN the cursor in the Execution Section. 3)FETCH the data from cursor into PL/SQL variables or records in the Execution      Section. 4)CLOSE the cursor in the Execution Section before you end the PL/SQL Block.
These are the three steps in accessing the cursor. 1) Open the cursor.
2) Fetch the records in the cursor one at a time.
3) Close the cursor. 

Example: Fetch the Records in the Cursor

Oracle Basic PL/SQL with examples

L/SQL Body

PL/SQL Statement start with BEGIN keyword and close with END keywords. In this example, you tell PL/SQL do nothing for you (null);

Use the slash (/) to compile and run the block.
PL/SQL Declaration

The DECLARATION statement will be used to define program’s variables, cursor, type, etc. In this declaration, you have no variable or cursor defined.


When you use the DBMS_OUTPUT.PUT_LINE procedure, the procedure will write the passing string into the Oracle buffer. In order to print the content of the Oracle buffer, you should use the SET SERVEROUTPUT command to display the content of the Oracle buffer into your screen. 

Write a PL/SQL block, to output the "First PL/SQL Procedure" message.

Open Source Hardware

Open source hardware, means free and open source software the same way as the design of computers and electronic hardware. Open source hardware started to consider areas outside of the open source software is open source culture.
The term is mainly used to reflect the release of detailed information on free hardware design, such as schematics, bill of materials and board layout data, commonly used open source software to drive hardware.

Shared logic design with programmable logic devices and the Reconstruction, is a form of open source hardware.
Some open source hardware projects are:
ECB AT91 - Information on Atmel AT91RM9200 ARM9 processor (180 MHz) single-board computer
ECB ATmega32/644 - based on Atmel ATmega32/644 (20 MHz) single board computer, network server performance, and less than 100mA of power consumption
Simputer - for developing Pocket PC
Open Graphics Project aims to design an open architecture and standard graphics.
Sun Microsystems OpenSPARC is a contribution to the …

Why Open Source software's are Popular

The current Open Source software's popularity is evident. From the embedded Android platform to the desktop platform Ubuntu, Firefox and Chromium and then to the server platform, LAMP, or is growing rapidly and swallowed the market, or have laid most of country. Ordinary users will not care whether an open source software, the kind of license agreement. Their only concern is to not spend the money to spend at least the best software. So why Open Source Software's are cheaper and easy to use it?

1. Free

The most attractive place to open source software, there is no doubt that it's free. Hundreds of thousands of Windows compared to the price of free communication, free use of the Ubuntu already a major step forward. For embedded systems, open source systems can reduce equipment costs, benefits consumers is also an indisputable fact.

2. High Quality

Excellent open source projects are often able to attract a lot of technical talent to assist in the development. So the final rel…