Adventures in Red Hat Enterprise Linux, CentOS, Fedora, OpenBSD and other open source solutions.

How google works

Google signHere is a quick presentation on how Google manages their data and serves all those requests.

Be aware; this is not a SEO-thing, but more technical about machines, clusters, queries, etc. For people in this business it could be rather interesting to know how it is possible that on web-site serves millions of requests each hour. This is done by introducing a cluster of several locations. Wow, I'd like to have a website that popular!

Generating traffic to your website

The big quest for traffic is on! It is actually on for quite some time already. Finding new ways to generate (targeted) traffic to your website is exciting and here is things I have done, with their success rate.

Media Minimum price Traffic Generated daily Price per visitor
Google AdWords € 25,- per month 2-5 clicks € 0,50
Animated Homepage $ 15,- per slot 10 $ 0,-
Yahoo Search Marketing $ 50 per campaign 2-5 $ 0,50
Stubmleupon Advertising $ 5,- daily 100 $ 0,05

Animated Homepage is unique in the sense that their website redirects visitors to one of the available slots. There are 100.000 slots available, around 100 have been sold so far. About 250.000 visits are registered daily, so now you can own a piece of internet history for only $ 15,- which will generate 2500 visitors daily. Please bear in mind that these visitors are browsing around the internet, not specifically to buy your product, but to discover cool websites.

One thing to mention is the type if traffic you are looking for. If you are looking for targeted (location based) sales leads, Google AdWords and Yahoo Search Marketing are likely the best choices. To have more visitors on your website, Animated Homepage and stubleupon are a better pick.

Please bear in mind that you do not have to pay stubleupon to generate traffic, when people "thumb-up" your site, traffic is sent to your site automatically.

Actions to files scattered in directories

Here is a trick to do things to files scattered among different directories. This trick is not revolutionary, but seems under utilized.

Imagine this file structure:


If you would want to show the size of both files, you could use two commands:

ls -l /directory/specific-directory1/file
ls -l /directory/specific-directory2/file

But, imagine you would have a few thousand file, what would you do then?

ls -l /directory/*/file

Yes, it is simple, but is does work! You can use "ls", "tail", "rm" and so on. It is a feature of the shell. I use Bash.

Smiley prompt in BASH

Here is how to make your live easier by displaying a smiley when the last command succeeded, and an unhappy smile when the last command failed.

  1. Add a function into .bashrc Execute this command to add the function to your startup script:
    echo "smiley () { if [ \$? == 0 ]; then echo ':)';else echo ':(';fi; }" >> ~/.bashrc
  2. Change the prompt. You can either execute this command first, or just execute what is stated here to implement permanently
    echo 'PS1="\$(smiley) [\[email protected]\h \w]\$ "' >> ~/.bashrc
  3. Login to a new windows and test the results!If it does not work, remove the two lines you just added in ~/.bashrc

Advertising on Stumbleupon

One customer of mine wants more exposure, more traffic for his site. There are various tricks to achieve this, but here is what I found out about several services.

  1. Most services generate traffic only when your campaign is active. Stumbleupon generates traffic/stumbles even after your paid campaign has ended. If you have the feeling that your sites should be seen by others and you are willing to invest $25,- (or more), stumbleupon is a great way to generate more traffic.
  2. Loads of new visitors. This is true for other sources as well, but I measure that Stumbleupon generates an higher number of new users.
  3. Can be free. If you are one of the lucky to post something that is "thumbed up" by a few users, your traffic will grow, for free!

A comparable service is delivered by Animated Homepage that redirects traffic to one of its advertisers. Animated Homepage can also be compared to The Million Dollar Homepage.

The future of computing

Boing Boing featured a document from more than 40 years ago. Can't find that article anymore, sorry. But; here is my prediction for the coming 20 years.

  • All software will be web-based. We will not be using separated software for email, documents, websites, etc. This change has already begun with services like Google Apps. Worries like viruses, disk-space, hardware will be shifted to availability, connection, price per month, etc.
  • Operating Systems will transform into firmware. Nowadays lots of effort is put into Operating Systems, Microsoft, Apple, Linux, UNIX and others are now competing for a place on the market. These vendors will shift their effort to web-based services. Apple already has .mac. This will most likely include storage of a profile, that contains all personalized parts of an Operating System.
  • Work will be more mobile. People will not work from offices, but from home more often. Maybe "local personal offices" will develop, spaces that facilitate for all office equipment, but are not part of the corporate organization you are working for. Your employer or yourself will hire a place in such an area near your house.
  • Harddisks will be something for service providers, not for home/office usage. As everything will be stored "online", you will not buy a hard disk anymore. This trend is already starting; Flickr for example offers limitless disk space to store photos on, YouTube offers space to host videos on. These services will all consolidate to a few vendors. Google is likely to be one of those vendors.
  • Every devices that stores information will be connected. Music players, phones, cameras, keyboards, mice, screens and so on will store their configuration or content online. Imagine that next time you buy a phone or camera, you enter your credentials and all configuration will be set to your likings!
  • Collaboration is the next big thing. Slowly people are getting better at what they are doing, the infrastructure to connect minds is almost finished. To make the nest big step, people, countries and societies will need to work together to gain maximum result. International Space Station could be the beginning.
  • The Open Source principal will be more common for all kinds of items. People are afraid that their great product will be stolen by somebody who can produce it for less. This fear will be eliminated as people will realize that collaboration and sharing will improve products in the end.

Well, its the 27th of August 2007 now, print this page, put it in an envelope and write "Open in 2027 or later" on it...

Video embedded in websites

I am always jealous at apple for having those beautifully integrated videos on their website, but here is a description for a more simple alternative to embed videos in websites using Mac OS X.

Convert Active Directory "LastLogon:" time to (UNIX) readable time

Microsoft Active Directory stored dates in a specific format, quoted from a Microsoft support page:

The Active Directory stores date/time values as the number of 100-nanosecond intervals that have elapsed since the 0 hour on January 1, 1601 till the date/time that is being stored.
The time is always stored in Greenwich Mean Time (GMT) in the Active Directory.
Some examples of Active Directory attributes that store date/time values are LastLogon, LastLogonTimestamp and LastPwdSet.
In order to obtain the date/time value stored in these attributes into a standard format, some conversion is required. This article describes how this conversion can be done.

UNIX/Linux stores time in seconds since 01-01-1970. To convert the Microsoft Active Directory timestamp, use this formula, as written in Bourne Again Shell:

echo $((($WindowsTimeStamp/10000000)-11676009600))

When searching the internet, you will find many formulas that use the number 11644473600. This is the number of seconds since 31-12-1601, which is used to calculate the "accountExpires" value. The values "lastLogon" and "lastLogonTimeStamp" however use 01-01-1601 as the date to calculate this value.

Be aware, "LastLogon" and "LastLogonTimeStamp" are only synchronized once each 14 days! To find the most recent value, you'd have to query each Domain Controller in the network.

To convert a UNIX timestamp to human readable time, use this Bourne Again Shell command:

date -d "1970-01-01 $UNIXTimeStamp sec GMT"

Office hippies

Check out this set of great images about Office Hippies.

Office Hippie Office Hippie Office Hippie Office Hippie
Office Hippie Office Hippie Office Hippie Office Hippie
Office Hippie Office Hippie Office Hippie Office Hippie
Office Hippie Office Hippie Office Hippie Office Hippie

Overview of energy consumption of LCD screens

How does one measure the efficiency of an LCD monitor? It is not only the amount of energy consumed, but also the amount of pixels, the physical dimensions, the amount of light it emits, the contrast the determine how "efficient" a monitor is.

In the table below, the efficiency is calculated like this:

(Pixels width * Pixels height) / Energy usage * Dimension * Light emission * Contrast Ratio /

Here are some results:

Brand Type Energy usage WATTS Pixels width Pixels height Dimension (diagonal) in INCHES Light emission in CD/M2 Constrast ratio in X:1 Efficiency (Higher = better)
Hewlett Packard HP LP2465 75 1280 1024 24 500 1000 368.64
Samsung SyncMaster 931C 38 1280 1024 19 250 2000 327.68
Apple Cinema Display M9179LL/A 150 2560 1600 30 400 700 229.38
Hewlett Packard HP LP3065 176 2560 1600 30 300 1000 209.45
Belinea 1925 S1W 36 1440 900 18 300 850 165.24
Apple Cinema Display M9178LL/A 90 1920 1200 23 400 700 164.86
Hewlett Packard HP 1955 40 1280 1024 19 250 1000 155.55
Sun Microsystems AI24po 112 1920 1200 24 300 750 111.09
Apple Cinema Display M9177LL/A 65 1680 1050 20 300 700 107.20
Philips 170S5FB 30 1280 1024 17 250 450 83.56
Hewlett Packard HP 2035 75 1600 1200 20 250 500 64.00
Hewlett Packard HP 1740 75 1280 1024 17 300 500 44.65

By adding an entry, you will be able to calculate the efficiency. We will review the entry and possibly add it to this list.

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