Fedora Linux 12 is out today

Fedora Linux 12 is out today.

Here are the links to download Fedora 12:

  1. Download Fedora 12 64-Bit
  2. Download Fedora 12 32-Bit
  3. Download Fedora 12 PowerPC
  4. All versions

Suggestions:
I found that the downloading speed varies depends on which mirror you get. I suggest to test the download speed first, and re-try it (using a different mirror) if the speed is too slow.

For example, run the following command in terminal:

wget http://download.fedoraproject.org/pub/fedora/linux/releases/12/Fedora/x86_64/iso/Fedora-12-x86_64-DVD.iso

Which will show you the speed. Simply terminate the command and re-try it if the speed is too low.

Have fun with Fedora 12.

–Derrick

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[Solved]Cisco RVS4000 4-port Gigabit Security Router – Slow

Recently we bought a Cisco RVS4000 4-port Gigabit Security Router and we noticed that the connection speed to the Internet was extremely slow. If we connected the server directly to the Internet (Without going through the Router), the download speed was around 80MBps, while the speed dropped down to 30 ~ 40MBps with the router with the default setting.

After disabling the IPS, the problem was gone!

Steps (IPS)- Required

  1. Go to the control panel (http://192.168.1.1)
  2. Go to the IPS tab
  3. Go to the Configuration Tab
  4. Disable the IPS function

Cisco RVS4000 4-port Gigabit Security Router - Slow Speed

Steps (Firewall) – Optional

  1. Go to the Firewall Tab
  2. Enable Firewall, DoS Protection and Block WAN Request
  3. Disable the rest

Cisco RVS4000 4-port Gigabit Security Router - Slow Speed

Looks like the IPS feature took too much resource from the router CPU.

–Derrick

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Ruby On Rails gives no “surprise” in the latest version

I haven’t upgraded my Ruby On Rails and related Ruby gems for 5 months. One of the reasons is that Rails development team likes to break the backward compatibility, such as:

NameError: uninitialized constant ApplicationController

To avoid this kind of surprises, I tend to stick with a working, stable version.

Recently, I upgrade the entire Ruby On Rails family(2.3.2 -> 2.3.4), and surprisingly, my Ruby On Rails apps work perfectly fine! One exception is that the Mongrel server behaves a little bit slower than before. One way or the other, we need to use the load balancing technique to host the Rails App anyway. So it really doesn’t matter.

In case you want to try upgrading your Ruby Gems and other things:

Update the Ruby Gem Engine:

sudo gem update --system

Update other Ruby Gems:

sudo gem update

–Derrick

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Updated: What technologies (or toys) I am playing recently?

Recently I am playing the following technologies (toys):

  1. Tornado Web – Not sure how long will Apache + PHP last. Time to learn Python.
  2. Tokyo Cabinet & Tyrant – Another one of my long term plans to step away from SQL.
  3. PHP API for Tokyo Tyrant — I decide to write my own because I cannot find a good one.
  4. Moving my development platform from Windows to FreeBSD. My servers have been already on FreeBSD for many years. I think now is a good time to move my desktop systems to FreeBSD as well. Why not Linux? Oh Well…
  5. LUA – I may pick up Lua if time is permitted.

Looks like I will have a busy time other than shoveling the snow this Winter.

–Derrick

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[Solved]Snow Leopard (OS X 10.6.2) can’t boot after upgrading to 10.6.2

After upgrading to Snow Leopard (OS X) 10.6.2 from 10.6.1, I found that my system could not boot, no matter what option I chose at the boot prompt (-x, -v, -s etc). After trying for nearly half an hour, I was about to give up. Finally, I tried replacing the kernel and it rocked! I think I should share my solution here because I couldn’t find something like that on Google.

What I did:
Replacing the kernel of OS X 10.6.2 by OS X 10.6. You can find the old kernel from your backup (if you have), or from the Snow Leopard installation disk.

Steps:

  1. Grab your OS X 10.6 installation disk.
  2. Boot the system using the external DVD-Rom or USB Flash Drive.
  3. After booting to the installation screen, select your language and continue.
  4. Open Terminal
  5. Type the following:
cp /mach_kernel /Volumes/XXX/

where XXX is the name of your system directory. If you are not sure how to find it, you can try to run:

df

Warning(Side Effect):
When the system upgrades to OS X 10.6.2, it upgrades both the kernel (the brain) and the apps (the body) to 10.6.2. Now, we are downgrading the brain back to 10.6. It may cause unexpected behavior because the brain and the body are speaking different languages. You can think about the problem this way: The brain is speaking an old language while the body understands the new language only. Will they get along together? May be. Only Apple knows the answer.

So do it at your own risk.

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Installing Apache on Snow Leopard (OS X 10.6)

The Apache web server comes with the OS X is a bit out dated. So I decided to install a new one. After I tried installing it using mac port, it kept giving error.

Finally, I built the Apache from source, and it worked!

Grep Apache from here.

Download the file, where the link should look something like:

Unix Source: httpd-2.2.14.tar.gz

Run the following command in terminal:

tar -zxvf httpd-2.2.14.tar.gz

cd httpd-2.2.14

./configure

make

sudo make install

That’s it! Now, let’s test the webserver.

First, let’s disable the Apache that shipped with the OS X (Not the one you just install!). You can simply do it by going to:

System Preferences -> Sharing -> Web Sharing

Go back to Terminal. Make sure the default web server is not running:

sudo apachectl stop

Now, let’s verify the installations:

/usr/local/apache2/bin/apachectl -v

You should see something like this:

Server version: Apache/2.2.14 (Unix)
Server built:   Oct 24 2009 20:53:45

Now, let’s start the web server:

sudo /usr/local/apache2/bin/apachectl start

Open your browsers and access to http://localhost/.
You should see something like:

It works!

Have fun!

–Derrick

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IE is “fxxking”, but it is not an excuse to leave bug in the codes

Today, my co-worker found that the web-application he developed worked only in Firefox, and it didn’t work in Internet Explorer(IE). He immediately asked me if we should ignore the IE users or not.

I know that he was working on JQuery(Javascript). It is not surprised that IE does not support the standard JQuery. However, it doesn’t mean that we can simply remove our support to IE users. In fact, IE still have more than 55% of market share today, while Firefox have around 30% only.(See here for more information) It’s too early(and not responsible) to ignore such a large user group.

So, after he complained about how fxxking the IE was for an hour, I tried to find out that the problem. I found that the problem came from his code rather than from IE. He had an extra tag in his code. Firefox was so smart to catch the error and ignore it. That’s why it only worked in Firefox, but not in IE.

So, here are what I’ve learned today:

  • The error catching function introduced in Firefox is so good. But at the same time, it makes some developers lazier by not verifying the quality of their works. They will think it is your problem if you are using IE.
  • IE sucks, but it is not an excuse of leaving the IE users behind.
  • Complaining has nothing to do to improve the problem. Talk is cheap, do it.

Next time before you complain to your manager about how fxxking the IE is, think twice.

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It’s a pain to use Godaddy.com’s coupon!

Godaddy.com was running a sale today: $1.99 a domain name (Coupon Code: GEO199, no other purchase is necessary) for the first year. This is a very good deal so I decide to grab four domains from them. The pain began:

1. I couldn’t use the coupon code for four domains in the same order…

» Fine. I split the order into four. I didn’t have any problem on my first order.

2. I couldn’t use the coupon code on the same user account…

» Fine. I registered a new user account and tried again.

3. I couldn’t use the coupon code on the same browser…

» Fine. I cleaned up the cache and tried again.

4. I couldn’t use the coupon code from the same IP…

» Fine. I tried using a different IP…

5. I couldn’t use the coupon code with the same credit card…

» Fine. I tried using a different credit card…

6. Finally, I got four domains for $7.96. It’s a good deal but it already spent me half an hour.

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Can’t send mail from Fedora Linux … Solved!

I was having problem today to send out an email from my Fedora 11 Linux box. By default, the mail server software, Sendmail, comes with the standard installation and no configuration is required. I didn’t understand why the Sendmail didn’t work.

After a very detail investigation, I finally found out why. Here are the steps I went through to solve the problem.

1. Make sure the Sendmail is running.

netstats -na | grep LISTEN

You should see something is running on port 25.

2. Make sure the stupid SELinux Firewall is disabled.

3. Make sure the Linux Firewall allows port 25.

4. Try to connect to the port 25.

telnet localhost 25

If you have trouble to connect to the port, that means something is not work.

5. Make sure you are not blocking port 25 at the system level:
In /etc/hosts.allow

sendmail: localhost: allow

That should work!

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The Flying Saucer Balloon at Colorado

Why no one thought about taking a picture of the flying balloon using infra-red camera? The Raytheon one should do the work.

Click here to read the ridiculous story.

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