Aan Kurniawan ¹ and Zainal A. Hasibuan ²
Faculty of Computer Science, University of Indonesia
email: aan.kurniawan@ui.ac.id ¹, zhasibua@cs.ui.ac.id ²

ABSTRACT

Educational resources usually reside in the digital library, e-learning and e-laboratory systems. Many of the systems have been developed using different technologies, platforms, protocols and architectures. These systems maintain a large number of digital objects that are stored in many different storage systems and data formats with differences in: schema, access rights, metadata attributes, and ontologies. This study proposes a generic architecture for sharing educational resources in the heterogeneous environments using data grid. The architecture is designed based on the two common types of data: structured and unstructured data. This architecture will improve the accessibility, integration and management of those educational resources.

As the network administrator who manages more than 300 computers which are spreaded into several buildings, changing local administrator’s password is a boring routine. Fortunately, Windows provides some tools and scripts in the form of command line which help this job done in seconds.

When you move or copy (migrate) all databases between SQL Server instances, sometimes you need to preserve information about logins and their passwords. The following script will generate an sql script that recreate the logins as well as the passwords from the previous instance.

When making a query that needs joining two or more tables, you need to know the primary key/s of the tables.
The command DESCRIBE <TABLE_NAME> will not show you the primary key.
To get the primary key, use this query:

SELECT B.COLUMN_NAME FROM ALL_CONSTRAINTS A, ALL_CONS_COLUMNS B
WHERE A.CONSTRAINT_NAME=B.CONSTAINT_NAME AND A.OWNER=B.OWNER AND
A.TABLE_NAME=<TABLE_NAME> AND A.CONSTRAINT_TYPE='P';

Change <TABLE_NAME> with the table name.

Like telnet, all communications between MySQL server and its client, including username and password, are transmitted in plain text. It allows everyone to sniff on your session and get your password and other valuable information.

The following method ensures a higher security level on the connection between MySQL server and its client. The communication between them is done on the SSH tunnel which is more secure because it uses encryption.

In a network environment with heterogeneous OSes, sometimes we need to access some files in another computer that uses different OS. As I often do when developing an application that will be used mostly by Windows users, I need to access some of their shared folders. This tutorial explains how to mount a Windows shared folder to a Linux directory automatically every time our Linux computer reboots.

These children make me enjoy my life as their parent.

To change hostname in Ubuntu, modify the file /etc/hostname. This file contains the host name. Change the old name with the new one and then save the file. Do the same thing for the file /etc/hosts. Run the script /etc/init.d/hostname.sh to make the changes effective or just reboot the host using the command shutdown -r now.

In Ubuntu, don’t forget to always use sudo <command> to make critical changes on configuration since we usually do not use root account. So, the complete commands for changing hostname in Ubuntu are :
prompt>sudo vi /etc/hostname (change the old host name with the new one)
prompt>sudo vi /etc/hosts (idem)
prompt>sudo /etc/init.d/hostname.sh (make the changes effective)

I can open a shared folder of windows system from my ubuntu using this command line:

sudo mount -t smbfs -o username=<my_windows_account> <//path_to_the_shared_folder> </mount_dir>

For example : The path of the shared folder is //myserver/mydir (use ‘/’ instead of ‘\’ in linux system) and the mount directory in my linux is /mnt/windir. My Windows domain is COMPANY and my account in the domain is aan. So, the command is :

sudo mount -t smbfs -o username=”company\aan” //myserver/mydir /mnt/windir

After I press <Enter>, the linux will prompt password, and I type my password in the COMPANY domain.

Another command that can be used to provide the same function is as follow:

sudo smbmount //myserver/mydir /mnt/windir -o username=”company\aan”

Note:

We have to ensure that our ubuntu system has smbfs installed.

Use this command to install it:

sudo apt-get install smbfs