Entries Tagged as 'Cool Stuff'

HandBrake for MP4

Thanks Jeffrey Ai who told me a nice tool to convert many formats of Movies to MP4(MV4) format. Especially, it can be working on Mac OS and Linux platform. The download link and details are listed at: http://handbrake.fr/

iPod Touch Vulnerability after Jailbreak

As you may know or may not know, there is a vulnerability for iPod Touch after jailbreak. The root password is hard-coded as “alpine”. If your iPod Touch connect to the hotspot network, people who is in the same subnet can do the following:

  1. Nmap the whole subnet.
  2. sudo nmap -A -O -T4

  3. The scan result will be shown as follows.
  4. Interesting ports on ******* (
    22/tcp open ssh OpenSSH 5.2 (protocol 2.0)
    62078/tcp open tcpwrapped
    Running (JUST GUESSING) : Apple embedded (93%), Apple iPhone OS 1.X (89%)

  5. Then, the most likely what the people want to do is:
  6. ssh root@
    Password: alpine

  7. Then, as you can guess, they want to do whatever they want.
  8. John-Smiths-iPod:/ root# ls
    Applications@  Library/  User@  boot/   dev/  lib/  private/  tmp@  var@
    Developer/     System/   bin/   cores/  etc@  mnt/  sbin/     usr/

The solution is very simple: just to change root password after jailbreak. We can go to terminal application in the iPod.

  • Type su – to enter super user mode
  • Type passwd to enter the new password
  • Type again the new password
  • Type exit. We are done.

Good luck and Thanks,

Trac on Ubuntu

I am looking for some platform can manage some projects and share some ideas. I have used Twiki which implemented by Perl and I have also used Tikiwiki which implemented by PHP. However, people recommended that Trac is good for development project. The benefits are as follows:

  • SVN to manage code check-in/check-out
  • Wiki page to have document for each changes and implementations.
  • Bug preview and bug tracking
  • More…

So, I followed the TracOnUbuntu to install. I still need time to figure out how to maintain the system.


Besides the link above, there are two things need to be considered.

  1. sudo chmod -R +w /var/lib/trac/, otherwise, the web page will throw exceptions.
  2. sudo htpasswd -c /etc/apache2/dav_svn.passwd username, otherwise, you can’t login to revise wiki page.

Linux Kernel 2.6.24 – (2)

Let’s continue to view what’s new on Linux Kernel 2.6.24.

1. SPI/SDIO support in the MMC layer

MultiMedia Card (MMC) subsystem maintainer Pierre Ossman described what he plans to push upstream, “this release will probably be one of the biggest ones for the MMC layer so far. The major pieces are SDIO and SPI support, but there are several small nuggets as well.” Regarding the new Secure Digital Input Output (SDIO) stack he noted, “gone are the days of having to rely on proprietary stacks for SDIO support in Linux.

2. USB authorization

As part of the efforts to make the USB layer ready for wireless USB, Linux 2.6.24 is getting support for USB device authorization, which allows you to control if a USB device (wireless or not) can be used or not in a system.

3. Per-device dirty memory thresholds

When a process writes data to the disk, the data is stored temporally in ‘dirty’ memory until the kernel decides to write the data to the disk (‘cleaning’ the memory used to store the data). A process can ‘dirty’ the memory faster than the data is written to the disk, so the kernel throttles processes when there’s too much dirty memory around. The problem with this mechanism is that the dirty memory thresholds are global, the mechanism doesn’t care if there are several storage devices in the system, much less if some of them are faster than others. There are a lot of scenarios where this design harms performance. For example, if there’s a very slow storage device in the system (ex: a USB 1.0 disk, or a NFS mount over dialup), the thresholds are hit very quickly – not allowing other processes that may be working in much faster local disk to progress. Stacked block devices (ex: LVM/DM) are much worse and even deadlock-prone (check the LWN article).

4. PID and network namespaces

Linux 2.6.24 adds PID namespaces and basic support for network namespaces. They’re used through the CLONE_NEWPID and CLONE_NEWNET clone() flags.

5. Large Receive Offload (LRO) support for TCP traffic

LRO combines received tcp packets to a single larger tcp packet and passes them then to the network stack in order to increase performance (throughput). After many out-of-the-tree iterations, mainline Linux is getting support for this feature

6. Task Control Groups

There have been various proposals in the Linux arena for resource management/accounting and other task grouping subsystems in the kernel (Resgroups, User Beancounters, NSProxy cgroups, and others). Task Control Groups is the framework that is getting merged in 2.6.24 to fulfill the functionality that lead to the creation of such proposals.

7. Linux Kernel Markers

The Linux Kernel Markers implement static probing points for the Linux kernel. Dynamic probing system like kprobes/dtrace can put probes pretty much anywhere. However, the scripts that dynamic probing points use can become quickly outdated, because a small change in the kernel may trigger a rewrite of the script, which needs to be maintained and updated separately, and will not work for all kernel versions.

8. Read-only bind mounts

Read-only bind mounts (mount –bind) allows a read-only view into a read-write filesystem. In the process of doing that, it also provides infrastructure for keeping track of the number of writers to any given mount. This has a number of uses. It allows chroots to have parts of filesystems writable. It will be useful for containers in the future because users may have root inside a container, but should not be allowed to write to somefilesystems.

9. x86-32/64 arch reunification

When support for the x86-64 AMD architecture was developed, it was decided to develop it as a “fork” of the traditional x86 architecture for comodity reasons. Many patches needed to patch a file in the i386 architecure directory, and another similar patch for the duplicated file in the x86_64 directory. It has been decided to unify both architectures in the same directory again.

Note: All quoted description is from kernelnewbie.org.

What’s New on Linux Kernel 2.6.24 – (1)

Linux Kernel released a stable version 2.6.24. According to one of Linux Editor, Marius Nestor, The release is the hottest Linux kernel ever! Why? Several improvements are as following:

1. Improved CFS

Briefly, CFS allows you to safeguard your files in encrypted form in a normal directory. By using a key (or password, if you will), you temporarily decrypt your files to clear-text form for the window of time in which you need to work with them.

2. Add Tickless feature for x86-64?PPC?UML?ARM?MIPS architecture.

“The tickless kernel feature (CONFIG_NO_HZ) enables ‘on-demand’ timer interrupts: if there is no timer to be expired for say 1.5 seconds when the system goes idle, then the system will stay totally idle for 1.5 seconds. This should bring cooler CPUs and power savings: on our (x86) testboxes we have measured the effective IRQ rate to go from HZ to 1-2 timer interrupts per second.

“This feature is implemented by driving ‘low res timer wheel’ processing via special per-CPU high-res timers, which timers are reprogrammed to the next-low-res-timer-expires interval. This tickless-kernel design is SMP-safe in a natural way and has been developed on SMP systems from the beginning.”

3. Patch for Anti-fragmentation

The anti-fragmentation strategy has memory overhead. This patch allows
the strategy to be disabled for small memory systems or if it is known the
workload is suffering because of the strategy. It also acts to show where
the anti-frag strategy interacts with the standard buddy allocator.

4. New wireless drivers and configuration interface

(To Be Continued…)

Quicksilver and Lao-Tze

Recently I noticed Quicksilver about page. It’s really cool since it put Lao-Tze’s words on that, who was the “Old Master” lived in China Thouthands years ago. Thanks Mitchell for translation. I can still taste the “Dao De Jing” from the words.

About Quicksilver

3D Desktop on Fedora 7

I always think Java cannot do something about desktop better than others, until I saw the project named Looking Glass 3D desktop environment on Linux. Although I can enable desktop effect on Fedora 7 and make it looks fancy, it is still not as innovated as this project does. Okay, let’s take a look.

Step 1: Download the binary file


Step 2: Extract the binary file and post install

mv lg3d–1-0-0-linux-i686-0612190943.bin /usr/share/
bash lg3d–1-0-0-linux-i686-0612190943.bin
cd /usr/share/lg3d/bin/
bash ./postinstall

Step 3: Enjoy Looking Glass 3D

/usr/share/lg3d/bin/lg3d-app OR

Screen Shots 1: Desktop and Menu
Desktop and Menu

Screen Shots 2: Choose Desktop Background

Choose Desktop Background

Screen Shots 3: Transparent Terminal

Transparent Terminal

K-lite Codec Pack 3.4.5

I have experienced installing four codec packages only for viewing a movie before. I also have had to install third party software to listen MP3 music. Now, there is a K-lite package, which is good for Windows multimedia users since it provides many codec format just in one package.

Free Download


Start to install


Choose options




Pros and Cons

Pros Cons
Support Audio: AC3Filter, MP3/MP4, Ogg, Wav, rm  
Support Vedio: MPEG4/DVD, DivX, Xvid, rm Quick time is not default option
Support DirectVobSub for subtitle Only provides .exe installation file, which means, the package can only install to the Windows.