Aspire ONE (Model 0751H) GMA500 widescreen display setup on Fedora 14

Before installation of the problematic Poulsbo driver on Ferdora 14 (freshly installed), please try the followings first:

$ su -c 'yum clean all'
$ su -c 'yum update'

Reboot to let the updated kernel running.

Install rpmfusion free and non-free repositories rpms:

$ su -c 'yum localinstall --nogpgcheck \
http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm \
http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm'

Thanks to AdamW's articles, the correct steps are listed here:

To install Poulsbo driver:

$ su -c 'yum –enablerepo=rpmfusion-nonfree-updates-testing \
install xorg-x11-drv-psb'

To fix the problem of missing psb.ko for whatever updated kernel:

$ su -c'yum –enablerepo=rpmfusion-nonfree-updates-testing \
install akmod-psb'

Reboot to take effect for widescreen display.

Optimize the following sections in /etc/X11/xorg.conf:

Section "Device"
Identifier  "Videocard0"
Driver      "psb"
Option      "IgnoreACPI"
Option      "MigrationHeuristic" "greedy"
Option      "ShadowFB" "true"
EndSection

Section "Extensions"
Option     "Composite" "Enable"
EndSection

Section "Screen"
Identifier "screen1"
Device "Videocard0"
DefaultColorDepth 24
EndSection

Section "DRI"
Mode 0666
EndSection

Edit /etc/grub.conf as follows:

Add the following parameters to the end of line of kernel command:

elevator=noop mem=896m acpi_osi=Linux acpi_backlight=vendor

Reboot and see if the system performance is improved.

An Open Source version of RedHat Enterprise Linux

I have been looking for other alternatives which mimics or offers free version of Enterprise OS like RedHat Enterprise Linux. Two of them have been found so far, like CentOS and Scientific Linux.

RHEL6 has been released for a while but CentOS didn't quite catch up with the latest version of RHEL, so I turned to use Scientific Linux which has version 6 now. Also, the fancy of SL6 may be due to its support by famous national laboratories around the world, such as Fermilab and CERN. These labs are working on high energy physics and make use of SL6 inside their IT infrastructure.

SL6 is actually rebuilt from the source RPMs of RHEL6. People are working on security fixes and put them upstream back to RedHat repository. This makes SL6 binary compatible with RHEL6. Now I use SL6 on my Aspire ONE netbook as well.

The good thing that I have experienced is the high quality of software packages as compared with other open source edition of Linux which may crash and make your system useless in some occasions. You may not obtain the latest update in time but the stability and reliability offered by typical enterprise class system is certain.
Although "Scientific" is not a cool name to me, it is surely a good choice of enterprise class OS in production environment.

Site reference:
http://www.scientificlinux.org/

User Privileges for MySQL administration and automation

To automate MySQL administration like using auto backup script, the user privileges play an important role on how MySQL server to be control with enough security measures to prevent mis-using such user role.

Assuming "mysqldump" and "mysqladmin" are going to be used in such automation, the following privileges should be clearly identified and applied to a particular user role for successful MySQL administration:

• SUPER
• SELECT
• SHOW DATABASES
• SHOW VIEW
• LOCK TABLES
• RELOAD
• SHUTDOWN
• PROCESS
• REPLICATION SLAVE
• REPLICATION CLIENT

Example of assigning privileges:

>c:\xampp\mysql\bin\mysql –u –p –-port=3306
Enter password: ************

mysql>CREATE USER ‘replica’@’localhost’ IDENTIFIED BY ‘password’;
mysql>GRANT REPLICATION SLAVE ON *.* TO ‘replica’@’localhost’;

For details of particular privilege, please refer to the manual page:
http://dev.mysql.com/doc/refman/5.5/en/privileges-provided.html

Converting EXT3 partition into EXT4 on Ubuntu

EXT4 type partition is the successor of EXT3, but it may not be turned on by default installation. Indeed, EXT4 driver is backward compatible with EXT3/EXT2 partition. The conversion from EXT3 to EXT4 partition is straight forward.

Please backup important data and software you have been using on Ubuntu Linux.

BEFORE DOING ANYTHING, PLEASE SHUTDOWN ALL LAMPP RELATED PROCESSES:

$ sudo /opt/lampp/lampp stop

To switch the existing Ext3 file system to the new Ext4 driver, it is necessary to edit a configuration called "fstab":

$ sudo nano /etc/fstab

Look for ext3 on the line that defines your disk and change it to ext4.

To ensure the right device to be converted, you may check the name of the device by issuing the following command:

$ df -h

Make a note of the device as you will need it in the next step. In the example above, the device for the encrypted partition is "/dev/mapper/encrypted".

Next reboot your system. This is required so that you switch to the Ext4 Kernel driver. Do not continue without rebooting first.

Enable Ext4 features:

$ sudo tune2fs -O extents,uninit_bg,dir_index /dev/mapper/encrypted

WARNING: Once you run this command, the filesystem will no longer be mountable using the ext3 filesystem!

After running this command (specifically, after setting the uninit_bg parameter), it is also important to run fsck to fix up some on-disk structures that tune2fs has modified:

$ e2fsck -yfDC0 /dev/mapper/encrypted

Notes:

Running fsck will complain about "One or more block group descriptor checksums are invalid" - this is expected and one of the reasons why tune2fs requests to fsck.
By enabling the extents feature new files will be created in extents format, but this will not convert existing files to use extents. Non-extent files can be transparently read and written by Ext4.
If you convert your root filesystem ("/") to ext4, and you use the GRUB boot loader, you will need to install a version of GRUB which understands ext4. Your system may boot OK the first time, but when your kernel is upgraded, it will become unbootable (press Alt+F+F to check the filesystem).
If you do the conversion for the root fs on a live system you'll have to reboot for fsck to run safely. You might also need to add rootfstype=ext4 to the kernel's command line so the partition is not mounted as ext3.

WARNING:
It is NOT recommended to resize the inodes using resize2fs with e2fsprogs 1.41.0 or later, as this is known to corrupt some filesystems.
If you omit "uninit_bg" on the tunefs command, you can skip the fsck step.

Installing open-vm-tools on Ubuntu Guest VM

To help boost the performance of Ubuntu Guest VM, it is recommended to install VMware tools. The problem is it may not fully compatible with various release of Ubuntu. Ubuntu do have their own repository of Open VM tools for use. So, why not have a try on it?

Installing open-vm-tools from Ubuntu repository:

The VMware tools are part of open-vm-tools. Make sure that the "multiverse" repository is enabled and do:

Install kernel headers so modules will work
We need this on a 10.04 guest running in a Fusion 3 host

$ apt-get install linux-headers-virtual

Install kernel modules

$ apt-get install --no-install-recommends open-vm-dkms

EITHER: install tools for an xorg install

$ apt-get install open-vm-tools

OR: a headless install

$ apt-get install --no-install-recommends open-vm-tools

Direct Upgrade Ubuntu from 9.04 to 9.10

Ubuntu upgrade from 9.04 to 9.10 can never be easy like this:

Before the actions, it is essential to backup any running database and web server for disaster recovery and then turn them off completely.

You can easily upgrade over the network with the following procedure.

1. Start System/Administration/Update Manager

2. Click the Check button to check for new updates.

3. If there are any updates to install, use the Install Updates button to install them, and press Check again after that is complete.

4. A message will appear informing you of the availability of the new release.

5. Click Upgrade.

6. Follow the on-screen instructions.

Finally, reboot the system and see all changes.

There was compatibility issue regarding XAMPP package since people complained they couldn't get XAMPP based server startup after the reboot. In my case, it did happen before. In recent trial of GUI upgrade directly from Ubuntu Update Manager, the problem seems to be solved. I have even got another notice from Update Manager about Ubuntu upgrade to version 10.04 as well.

Resync MySQL Slave with Master

For various kinds of reasons, it is not unusual to find MySQL Slave instance in a broken state during the replication. The quick fix requires a perfect database backup of Master instance. From the backup file, two parameters must be extracted for restoration of data onto Slave Server:

bin-log filename: MASTER_LOG_FILE
bin-log position: MASTER_LOG_POS

Of course, the overall system performance may be affected during the backup operation. However, MySQL Master server can be kept running as normal without any interruption.

You may find it difficult to find all the switches required for a successful online backup operation. Fortunately, an example is here.

Before anything happens, you'll find it easier to manage all those by opening two separate terminal consoles for both Master and Slave instances.

Terminal console for Master server:

The following command (recommended to run under “sudo –s” environment) will dump all databases on Master instance:

$ mysqldump -uroot -p \-S /etc/mysql/mysql.sock \
--master-data --hex-blob --opt --single-transaction \
--comments --dump-date --no-autocommit \
--all-databases > target_backup.sql

Please make sure the path of socket file of MySQL Master server is correct.

With “--master-data” switch, Mysqldump program will make a comment for the bin-log filename and position which can be really useful for resynchronization afterwards.

With “--single-transaction” switch, a global lock is acquired for a very short time at the beginning of the dump while any action on logs happens at the exact moment of the dump.

With “--hex-blob” switch, image data with BLOB type can be well preserved inside the backup without any disruption.

Once finished, you'll get a perfect backup file from MySQL Master server named "target_backup.sql".

Terminal console for Slave server:

Now, it is time to put the data onto MySQL Slave server. Please beware that the socket file used here becomes “/etc/mysql2/mysql2.sock”. Don’t it mix up with that of Master instance.

$ mysql -uroot -p -S /etc/mysql2/mysql2.sock < target_backup.sql

Now, login to MySQL Slave server:

$ mysql –root –p –S /etc/mysql2/mysql2.sock

Please check if MySQL user role named “slaveuser” with “replication” privileges does exist on Slave server.

Then, execute the following commands to resynchronize Slave server:

mysql> STOP SLAVE;
mysql> RESET SLAVE;
mysql> CHANGE MASTER TO MASTER_HOST=’localhost’,
>MASTER_PORT=3306,
>MASTER_USER=’slaveuser’,
>MASTER_PASSWORD=’XXXXXXXX’,
>MASTER_LOG_FILE=’mysql-bin.XXXXXXXX’,
>MASTER_LOG_POS=XXXXX
>;
mysql> START SLAVE;

For the corresponding values of MASTER_LOG_FILE and MASTER_LOG_POS, please read through the heading comments inside “target_backup.sql” file.

To check the status, please issue the following command:

mysql> SHOW SLAVE STATUS;

It is useful to check the error log of MySQL Slave server to confirm whether everything is back on track.

CeBIT Australia 2011

CeBIT 2011 is going to be held between 31 May 2011 and 2 June 2011. Both Technology Enthusiasts and Government Sectors are involved in this biggest event near Darling Harbour in Sydney. As I can imagine how many people will be there since last CeBIT event, it is definitely a good chance to meet top technologists and also listen to Julia about the new progress of the big plan for National Broadband Network.

Apart fromt the exhibition itself, there are upcoming hot topics to be discussed in the conferences. Major events include:

• NBN Conference
• Cloud Computing Conference
• eGovernment Forum
• eHealth Conference
• Executive Briefing
• Retail Conference
• WebForward Conference

 Can't wait to be there and hopefully see you in the exhibition!

PHP PDF generating over HTTPS issue on IE6 with blank page returned [REALLY SOVLED]

This is really a typical question raised at all time about mysterious IE6 PDF opening issue over HTTPS connection:


How can we successfully output PDF dynamically via HTTPS connection on various browser including IE6?


Whatever server-side language you use, you may encounter this yourself once or more in your life. As people trying to find a definite reason for this, it seems to be more than one anyway.


Say, using PHP, people encourage to add appropriate headers to make PDF stream opening on the fly directly in IE6 browser.

//size_of_stream is counted by bytes
//Display pdf text stream direct on the browser (IE bug fixed!)
//by setting the content-type


header("HTTP/1.1 200 OK");
header("Status: 200 OK");
header("Accept-Ranges: bytes");
header("Connection: Keep-Alive");


//Comment out for debugging purposes
//header("Cache-Control: public");
//Try setting 1 delta second for caching long enough for Adobe Addon to load PDF content
header("Cache-Control: public, max-age=1");
//Only need to specify User-Agent in Vary header as IE7 only accept that
//Default Vary header value is not welcomed at all
//Fixing IE7 bug for Vary header
header("Vary: User-Agent");
header('Pragma: public');
if (!is_null($size_of_stream)){header("Content-Length: ". $size_of_stream);}
header("Content-Type: application/pdf");
header('Content-Disposition: inline; filename="whatever.pdf"');
header("Content-Transfer-Encoding: binary\n");

This is almost true in many cases, including all the popular browsers like Firefox, Safari and Chrome. Yet there is still exception that PDF may not open properly on IE6, especially for small sized PDF stream.


Searching around for any server-side solution, it was really disappointed in terms of support of Internet Explorer 6.


Finally, I have a glimpse on a comment posted in the other forum which seems to work on almost any case with major version of Internet Explorer:


In Internet Explorer

1. Select Tools
2. Click Internet Options
3. Select the Advanced tab
4. Make sure "Do not save encrypted pages to disk" option near the bottom in the Security section is unchecked

This implies there is hardly any programming way to ensure PDF opening perfectly working.

Option "Do not save encrypted pages to disk" should only be enabled by default on Windows Server, whereas on most desktop PC the followings should be applied for security reason:

1. Go to the Tools menu
2. Click Internet Options
3. Click the Advanced tab
4. In the "Settings" box, scroll down to the section labeled "Security" 
5. click to check the box next to the "Empty Temporary Internet Files folder when browser is closed" option
6. Click OK to finish

This option does not delete cookies, but it will clear your cache of other files when you close your browser.

Now, the thing is how we are going to let people in an organization to follow this. This makes me unhappy:(

Related links:


http://joseph.randomnetworks.com/2004/10/01/making-ie-accept-file-downloads/#comment-670


http://robm.fastmail.fm/articles/iecachecontrol.html




However, this is not the end of the story.


To be enthusiastic for my work and diligent regarding all these, I keep digging deep into what's happening on a scenario which I have met in producing PDF on the fly.


For IE6, part of my PDF streams can be displayed correctly regardless of what option "Do not save encrypted pages to disk" disabled or not. When I tried to check the size of a successful PDF generated on the fly, they all show a bigger size like 120KB, 80KB or 76KB.


I did find some developer posts about the problem regarding PDF stream size to be displayed on IE. As I didn't remember wrong, someone mentioned about 8 Kilobytes in size to be minimum requirement on IE6.


When I go back to check that problematic PDF file by Firefox, it shows a size of 4 Kilobytes. Well, it's time to do an experiment on this.


Using PHP, it is easy to echo PDF stream first. Then you can calculate the size of stream by using function like strlen() to check size of string. Multiply this length by 1024, you'll get Kilobyte size yourself.

$len = strlen($pdf_stream)*1024; //length in bytes

Using simple algorithm to check it the length if it is less than 8192 bytes or not. When this is the case, you can first echo the PDF stream first.

echo $pdf_stream;

Then padding the spaces in advance:

for ($v=0;$v<=8192;$v++){
   echo ' '; //output space character
}

This makes sure the actual PDF output plus extra padding spaces occupying at least 8KB in size for IE compatibility.


Now, the problem is really solved across the browsers:)

Libgcc_s.so.1 bug on Linux

After a series of package installation onto Linux machine, some errors started to popup in the log. As found from a series of Google-search, it seems to be a problem widely spread among the software on Linux platform. This has been marked as a bug for attention.

Error message would be like this:

...libgcc_s.so.1: version 'GCC_4.2.0' not found (required by /usr/lib/libstdc++.so.6)...

This can happen on all kinds of software already installed onto the machine. People can barely find the cause until someone found a bug for this and suggest a fix - REMOVE IT!

However, it is safe to rename or move the problematic library to somewhere for retrieval. I would just rename it like this:

$ cd /destination_folder...
$ sudo mv libgcc_s.so.1 libgcc_s.so.1.bak

Sometimes you may want to check the file dependency before you take action:

$ ldd /destination_folder.../libgcc_s.so.1

The error should be gone so far.

Some useful materials can be found from the links below:
Fix "version `GCC_4.2.0' not found" for VMware 1.0.6 SErver and Ubuntu
`GCC_4.2.0' not found (required by /usr/lib/libstdc+