Tuesday, 27 February 2007

Screen estate and productivity

At my home office, I used 3 screens, the laptop connected to a second screen and a Mac (shown on the left). This is a big boost to my productivity as I can process more information at the same time (my internal bio-memory is small and leaking).

via Gismodo, I now learnt that there is a dual screen laptop. May be this is the beginning of multiple screens...

Monday, 26 February 2007

What the future will be?

Worth watching [6 minutes]

Friday, 23 February 2007

What's Special About This Number?

via BoingBoing

BoingBoing listed the first 11 numbers. Here is the next 10.

11 is the largest known multiplicative persistence.
12 is the smallest abundant number.
13 is the number of Archimedian solids.
14 is the smallest number n with the property that there are no numbers relatively prime to n smaller numbers.
15 is the smallest composite number n with the property that there is only one group of order n.
16 is the only number of the form xy = yx with x and y different integers.
17 is the number of wallpaper groups.
18 is the only number that is twice the sum of its digits.
19 is the maximum number of 4th powers needed to sum to any number.
20 is the number of rooted trees with 6 vertices.

Frankly, I don't a lot of the special properties, e.g.

Abundant Number [http://mathworld.wolfram.com/AbundantNumber.html] is a positive integer n for which

where sigma(n) is the divisor function and s(n) is the restricted divisor function. The quantity sigma(n)-2n is sometimes called the abundance. The first few abundant numbers are 12, 18, 20, 24, 30, 36, ... (Sloane's A005101). Abundant numbers are sometimes called excessive numbers.

There are only 21 abundant numbers less than 100, and they are all even. The first odd abundant number is

That 945 is abundant can be seen by computing

Any multiple of a perfect number or an abundant number is also abundant. Every number greater than 20161 can be expressed as a sum of two abundant numbers.

Mathematically oriented people surely will be interested in the whole list (from 0 to 9999) which only a few numbers without some significance.

Wednesday, 21 February 2007

Everything You Know About Disks Is Wrong

Here is another paper about failure of disk drives - and this one won the best paper award.

StorageMajo has a good summary. Robin Harris's conclusion is

After these two papers neither disk drive or array businesses will ever be the same. Storage is very conservative, so don’t expect overnight change, but these papers will accelerate the consumerization of large-scale storage. High-end drives still have advantages, but those fictive MTBFs aren’t one of them anymore.

Further, these results validate the Google File System’s central redundancy concept: forget RAID, just replicate the data three times. If I’m an IT architect, the idea that I can spend less money and get higher reliability from simple cluster storage file replication should be very attractive. [my emphasis]

Sunday, 18 February 2007

Failure Trends in a Large Disk Drive Population

google's engineers are presenting a study of disk drive failure at a conference and the 13-page paper is online. If you don't want to read the whole report, TG Daily has a fairly good summary.

The most interesting observation is:

temperature and high usage alone are not responsible for failures by default. Also, the researcher pointed towards a trend they call "infant mortality phase" - a time frame early in a hard drive's life that shows increased probabilities of failure under certain circumstances.

Why I am excited with VAF's break through? Part 1

In this part, I will describe my understanding of the technology behind the current state of play of Web 2.0.

Mesh up of data - mixing of data sources:

  1. Data sources (such as Google Map, Flickr, Criag's List, ...) expose sets of API for user to fetch a customised set of data from the data source.

  2. Data is returned typically in XML or JSON format.

  3. Mesh-up sites take two or more data stream from different data sources, select useful fragments from the returned data and mix with fragments of data from another source to create unique value-added service.

Note that:
  1. the APIs are server-based

  2. these APIs are called by server or web browser client (XMLHttpRequest is available both as a server process as well as implemented by most modern browsers.)

  3. Mesh-up is mixing CONTENT or data depending on how you like to call it.

The second trend is the injection of additional features on a web-page, typically using Greasemonkey extension using user scripts. I will group customised look and feel into the same category. Basically, if an end-user is not satisfied with a web-page, the web-page is changed using either a user CSS (to replace the original look and feel of the web-page) or an injected Javascript through the GreaseMonkey extension.

I still have not seen mixing of AJAX functionalities (ie the first trend above) with user injection.

This is important to note that in both these trends, the original data source or the web page owner is NOT designed to match and mix with any other data source. It is a third party who mixes the data sources or changed the style/functionality of the webpage.

The experiments I did in the VAF break through shows that data sources can also expose their API as a Javascript object/script and enable a pure web-browser based mesh-up. Data provide context, scripts provide functionality. I hope we can see people starting to provide functionality (in the form of javascripts) to allow users to manipulate data from different sources (such as GreaseMonkey script), and VAF will enable different scripts to work together.

恭喜发财 - Happy Chinese New Year of Pig

[Photo by 1980Nic from Flickr]

Tuesday, 13 February 2007

Break through in "Virtual Apparatus Framework"

A decade ago, I embarked on designing a framework for creating interoperable component for creating educational webpages. See Virtual Apparatus Framework.

The key for co-operative interoperability is to enable the components to share data and hence can act on what other component is doing. The technology I have chosen 10 years ago is based on the Netscape's LiveConnect. Different vendors have different level of support of this and hence the VAF has been working and breaking continuously.

Today, I jumped on the idea of sharing via DOM. Here are the experiments:
page from http://www.ipa88.com and page from http://www.scormplayer.com. These pages are exactly the same. Please verify using view page source.

The page loads two scripts, one from www.ipa88.com and another from www.scormplayer.com. All scripts from ipa88.com are numbered oddly while those from scormplayer.com are numbered evenly.

Does this method post a security risk? I don't think so because the loading page has explicitly requested the loading of scripts from two domains - i.e. that's by design!

I have tested on windows XP with only Firefox and IE6. Please let me know your testing result on other platform/browser combination.

Saturday, 10 February 2007

Creating a 3D effect with image editing software

This is a great tutorial by Andrew546. I am glad that it is illustrated using GIMP too.

[photo from one of the comments, by Kandykornhead]

Wednesday, 7 February 2007


from Google Video

BLOGUMENTARY playfully explores the many ways blogs are influencing our media, our politics, and our relationships. Personal political ... all » writing is the foundation of our democracy, but mass media has reduced us to passive consumers instead of active citizens. Blogs return us to our roots and reengage us in democracy. Shot in candid first-person style by director Chuck Olsen. NOTE: This film is presented here for non-profit, educational use only.

Pretty long, about 1 hour and 5 minutes. [May be worth the time to watch it if you have nothing more interesting to do.]

Tuesday, 6 February 2007

Web 2.0 ... The Machine is Us/ing Us

Click play. The next 4 minutes 31 seconds will be definitely a worthwhile and rewarding time for you - to understand what the web will be / should be.

vi many sources

Friday, 2 February 2007

MaestroLive is a Music Game

I have argued that Commerical Off the Shelf Games Will Not Work in Education. This position may need to change in light of the following program. But I am no music teacher, so I don't know how useful it may be.

MaestroLive is a Music Game. From the website:

MaestroLive is a music game that lets anyone play songs by tapping the rhythm of the song on a computer keyboard or on an attached MIDI keyboard. MaestroLive gives you a score for your performance. When you finish playing a song you can save your score to the MaestroLive network and compare it with previous scores of that song or with other player’s scores. Each song has its own set of scores.

# Choose a song from the MaestroLive Song List.
# Pressing any key on your computer keyboard will play the correct next event (an event is a single note or a group of notes).
# The rhythm radar in the center of the MaestroLive window provides you with a visual indication of when to play the next event.
# By pressing the computer keys in the correct rhythm (using the rhythm radar) you will be playing the song.
# You’re performance score updates while you play – when you finish playing the entire song you can save your final score to the MaestroLive network and compare it with the scores of other players of that particular song.
# MaestroLive can also teach you how to play "for real" if you attach a MIDI keyboard to your computer.

But you must download a program first in order to use it. It is free.