Server crash

My server experienced a major crash. I had to do an upgrade and backup all the essential user data. I found that network card with RTL8139 chip set was easily recognized by Redhat packages. The memory size of the hardware is now 320Mbyte and the HD storage is increased to 40G.

After the re-installation and re-configuration of named, sendmail, database, ftpd and httpd, everything resumed to normal working. An ultra-important thing to do was to register with redhat network and "up2date" the vulnerable packages.

No more crash, please, for God's sake.


Best viewed with Internet Explorer 5.0 / Netscape 4.7 or above

I find that many web sites still display a message at the bottom of the page that says :

"Best viewed with Internet Explorer 5.0 / Netscape 4.7 or above"

The message is unnecessary and confusing to users.

Many new browsers have emerged such as Mozilla, Firefox, Opera, K-meleon, Safari and Camino etc. They perform much better than IE. Another thing is Netscape has almost disappeared in the browser market. Less than 1 % of users are using Netscape right now.


Comcast DNS outage

Comcast is one of the US largest broadband Internet access providers with 7 million subscribers. On 7, 12 and 13 of April, there were three cases of DNS breakdown, each case hit at about 8 p.m. and lasted three to four hours. Users could not surf web sites or get email during those times.

Because of the unstable nature of Comcast’s DNS, some users have decided to manually configure their client PCs to use Verizon’s DNS servers. Sounds like these users are pretty clever.



昨日馬場發生自蘭桂坊以來的人踩人事件,原因只是為了換領紀念帽。數十人相 繼倒地,有人被踩踢受傷,有人被塌下的鐵馬壓傷,情況混亂,幸好沒有造成慘劇發生。



The world most powerful supercomputer

To date, the fastest supercomputer in the world is IBM Blue Gene supercomputer, measuring 70.72 TFLOPS. A speed test on 24th March 2005 demonstrated that the performance was rated at 135.5 TFLOPS.

Blue Gene is made up of 32768 processors, arranged in 32 racks, each rack holding 1024 processors. The processor used is 0.7 GHz PowerPC 440.


Daniel Julius Bernstein

Daniel Julius Bernstein (djb) is the greatest programmer in the software industry.

He has written the world most famous “qmail” and “djbdns”. In March 1997, djb announced to offer $500 to the first person to publish a verifiable security hole in the latest version of qmail. For 8 years, nobody has been able to get the money by finding out a single security hole in qmail.

According to djb, it is possible to write secure software if the programmer is sufficiently dedicated. He believes the widespread prevalence of security holes results from programmer laziness and incompetence.


Computer comics

To add funs to blogging, I post some computer comics here. They should make readers laugh.






Backup / Restore XP Activation

An article below about backup or restore XP activation on the same hardware config.

"When you activate Windows XP, Microsoft stores the data in the Windows Product Activation database files wpa.dbl and Wpa.bak in the folder %systemroot%\system32. If you change the motherboard or make significant hardware changes, XP will require you to reactive. But if you plan to reinstall XP on the same hardware, you can back up the activation status and then restore it after you reinstall and avoid the activation process. You can backup the Windows Product Activation database files to diskette. They are very small. A directory listing from my XP Pro workstation:

C:\WINDOWS\system32>dir wp*
Volume in drive C has no label.
Volume Serial Number is 8447-0571

Directory of C:\WINDOWS\system32

10/24/2001 08:28 PM 12,584 wpa.bak
01/14/2002 09:05 AM 12,642 wpa.dbl

After you reinstall XP, to restore the Windows Product Activation database files:

* Start XP to Minimal Safe mode
* Change directory to the \%systemroot%\system32 folder
* Rename the newly created wpa.dbl to wpa.nonactivated and wpa.bak, if it exists, to wpabak.nonactivated.
* Copy backed up wpa.dbl and wpb.bak files to the system32 folder
* Reboot

This should work if you want to avoid activating XP after a reinstall or restore on the same or very similar hardware. It will not work if the hardware is significantly different from that in place when the Windows Product Activation database files were created.

This is not a hack to avoid activating installations."


10 most influential people in IT history

Just for fun, I have voted the 10 most influential people in IT history :

1. Ken Thompson - founder of Unix

2. Vinton Cerf - founder of TCP/IP

3. Linus Trovald - father of Linux

4. Bill Gates - CEO of Microsoft

5. Steve Jobs - CEO of Apple Computer

6. Larry Ellison - CEO of Oracle

7. Marc Anderseen - he invented the first browser

8. Tim Bernes Lee - he invented the WWW standard

9. Richard Stallman - he fights for open source software

10. Bob Metcalf - he invented Ethernet


Shoreline Firewall

Shoreline Firewall (commonly known as Shorewall) is a very well-known firewall software in the Linux community. It is based on iptables on 2.4 kernel. Very flexible configuration allows the firewall to be used in a wide variety of firewall/gateway/router and VPN environments. The latest version is Shorerwall 2.2.






Funny words in software

Want to learn some funny words in software. Here are some :

Middleware - consists of software agents acting as an intermediary between different application components. It is used most often to support complex, distributed applications. The software agents involved may be one or many.

Demoware - is commercial software released by way of a free download in a version which is limited in one (or more) of the following ways:
  • Remains functional for a set number of days from installation.
  • May only be launched a set number of times.
  • Is limited to a set number of "days of use".
  • Program execution terminates after a set time period (typically between 5 and 60 minutes).
Nagware - (also known as annoyware) is a type of shareware, that reminds —or nags— the user to register it by paying a fee. It usually does this by popping up a message when the user starts the program or, worse, intermittently while the user is using the application.

Crippleware - programs are free versions of computer programs, lacking the most advanced or even the crucial features of the original program.

Hostageware - software that operates with major features blocked or limited unless the user provides payment in order to receive an "unlocking" code or similar enabling mechanism.

Careware - (or "charityware") is shareware for which either the author suggests that some payment be made to a nominated charity or a levy directed to charity is included on top of the distribution charge.

Shovelware - refers to software noted more for the quantity of what is included than for the quality or usefulness.

Beerware - a software license which provided an end user with the right to use a particular program (or obtain the source code) in exchange for providing some money to the authors so that they could buy beer.

Donateware - distributed as freeware, donateware stipulates that the user must donate to a charitable cause in order to "register" the software.

All these defintions can be found from wikipedia.



What is special about Security-enhanced Linux (SELinux) kernel ?

SELinux enforces mandatory access control policies that confine user programs and system servers to the minimum amount of privilege they require to do their jobs. When confined in this way, the ability of these user programs and system daemons to cause harm when compromised (via buffer overflows or misconfigurations, for example) is reduced or eliminated. This confinement mechanism operates independently of the traditional Linux access control mechanisms. It has no concept of a "root" super-user, and does not share the well-known shortcomings of the traditional Linux security mechanisms (such as a dependence on setuid/setgid binaries).

The latest versions of Redhat, Fedora, Gentoo, Susie are integrated with support of SELinux kernel.



About.com is great web site providing guidances on hundreds of topics; arts, literature, religions, recreation, travel, computing, technology, automotive, education, electronics, and food and drink.
This site has attracted 20 million visitors per month. Great work !








The Ten Commandments of PC Security

Journalist Daniel Tynan wrote the ten commandments of pc security published in a web site which I have forgotten the URL :

I. Remember thy antivirus software and keep it updated.

II. Thou shalt not covet thy neighbor's attachments.

III. Avoideth bogus file downloads.

IV. Smite spyware and pop-ups.

V. Thou shalt foil spammers.

VI. Keep thy operating system patched.

VII. Maketh a rescue disk and keep it handy.

VIII. Be not taken in by false claims.

IX. Honor thy firewall.

X. Maketh backups and keep them holy.

Well-thought and meaningful !




這些言論簡直不知所謂,曾蔭權是憑本身的才幹,智慧,加上三十多年的行政經驗,才可上這個位。連胡主席及溫總理都支持的人選,民建聯膽敢倒戈相向,豈不是對中央不滿嗎 ?



Gnome 2.10 Desktop

I have tried Gnome 2.10 desktop bundled in Ubuntu Linux 5.04 live CD.

It is very user-freindly and comes with a lot of useful tools :

Browser : Firefox 1.0, Epiphany 1.5
Email client : Evolution
Office suites : Abiword, OpenOffice
VCD/DVD player : Totem
Audio CD ripper : sound juicer

I read from news that Gnome 2.10 will be available in Fedora Core 4 to be released in May 2005. Feeling excited to try it out then. A screen shot of totem is captured below:


XPlay 2.1

For those people using ipod, they realize that Apple Computer only supplies itunes which transfers music files from PC to ipod. There are occasions when the reverse direction is required, just think of the situation of a PC crash and one needs to get back the music files from ipod to PC. Badly, itunes is not designed to offer the reverse transfer.

Xplay 2.1 can help to complement deficiency of itunes, but it costs US$30. The trial version will only be valid for 15 days.

I very much hope the next version of itunes can incorporate the features already found in Xplay 2.1. It is the fault of Apple Computer not to design itunes to have transfer in both directions.


2GB Gmail account

Google has announced that existing Gmail accounts will be expanded from 1GB to 2 GB.

The 2 GB capacity can only be fully utilized if one treats the Gmail account as an ftp account and makes the storage space as a Internet disk drive. For an average user, I don't think email alone could use up more than 30 %, or 600 MB.

I am not impressed by Google's move. Instead of giving out so much capacity, Google should better retain the Gmail account to 1 GB, but to open more accounts to new users.


IP to Country Search

By linking to the IP address database of http://www.hostip.info, I can play a gimmick below that shows the flag of a Net surfer's visiting country:

IP Address Lookup

The site www.hostip.info can also help to locate country by IP address. Woooo..... very nice service.


IP Address per person by country

Maxmind has published the IPv4 allocations of each country. I am interested in the allocations of US, China, India and Hong Kong. In terms of IP address per person, the following table can be drawn :

China and India are far lagging. As no many usable IPv4 addresses remain in the world, these two countries must go for IPv6.