CLOUD

It's often required to have a dual boot on any machine owing to the compatibility of the application software. I recently came across a real messy scenario where had to install Windows several times on my Ubuntu/XP dual-boot system. This is a bit risky case for two reasons. Ubuntu 9.10 comes with Grub2 and conventional Grub restoring methods would not be applicable and also Windows 2008-sp1 is know to be a very restricted OS with huge amount of security features. However, I managed to restore everything after installing Win 2008. Here are the steps that I followed. Following procedure will be valid on Ubuntu 9.10/Win XP, Vista, 2008, 7 You need the Ubuntu 9.10 live CD Boot from live CD Go to 'System->Administration -> Disk Utility' Find out the partition that you install Ubuntu (root). eg. 'sda4' Then open a terminal and mount the partition that you found above. ' sudo mount /dev/sdXY /mn t ' where X - Device Descriptor and Y-Partition Id ' sudo g...

In the context of modern IR Systems, using a dictionary or hash table to represent inversion list would be kind of tedious as it request huge amount of memory. There for its obvious that we need to get the help of secondary storage to store the content and retrieve when required. Then again there is a huge overhead of using secondary storage to store and read a dictionary. So the solution that we came across was B-Tree, which is a used almost each and every implementation of inverted index. Definition of a B-Tree of order ‘m’ A root node with 2 ~ 2m keys All the other internal nodes have between m ~ 2m keys All keys are kept in ascending order All levels have the same level of differ (at most 1) e.g: Inversion lists structures are used because they provide optimum performance in searching large databases. The optimality comes from the minimization of data flow in resolving a query. Only data directly related to the query are retrieved from secondary storage. The beauty of B-Trees lie...

Nowadays Sri Lankan music stream is flooded with a lot RnB and Hiphop music and many people merely want to listen to such styles of music. And all the radio stations are backing such music and ruining the natural music taste of Sri Lankans. All those commercial oriented artists tend to release their 5-6 tracks per a month. This is something simply related to the quantity and they simply want to create a music track using computers and other equipments. Once they create the track there are people who can write some strange words to tally with the track and the beat. Finally they’ll come up with a music video and all the TV stations eagerly waiting to play their music video.This is the story of Iraj, BnS, .. (you name it) But .. They have forgotten the fact that there are some (I think its few ) people in Sri Lanka who still loves the instinctive slow music (mood songs) which is a blend of soothing voices and acoustic music. Kasun Kalhara is one of the exceptions thrown from the Sri Lan...

‘Google’ – One of the innovative and revolutionary concept which was blossomed in early ‘96, as a research project of Larry Page and Sergey Brin (Google’s President incharge of Technology). Google only consume a spam of 13 years to climb to the peek of internet search technology and now, its in a state which is almost untouchable and unreachable to the competitors. I recently watch a nice interview with Sergey Brin and its really awesome as it reveals some of interesting facts about Google, it’s challenges and Sergey him self. Google manufactures Nothing! Yeah… it manufactures nothing but produce an IDEA. The idea or the mission is, ‘Accumulate all the world’s information and make it accessible and useful to everyone’. This sounds like an non-commercial or non-profitable but we should keep in mind that there is a underlying business process which may based on several revenue sources. In general, “Search Engines” use one or more of the following revenue sources. Charge advertisers for p...

‘Secondary Storage’ is still a nightmare in achieving higher performance in modern computer systems and often the power of multi-core CPU is more or less negate due secondary storage low performance IO. Of course the performance of secondary storage IO has improved in the recent past but it is still inferior relative to CPU performances. A computer must retrieve an item and place it in main memory before it can be processed. In order to overcome the low performances of the system one must organize the files intelligently and making the retrieval efficient. The file organization depends on the retrieval method; sequential or random. Particularly secondary storage IO is a huge overhead in the context of random access method. Therefore associated with a large, randomly accessed file in a computer system is an index. An index is often a file that stored in the disk and it contains a mapping between the terms and content. Inverted Index An index if often used in Information Retrieval system...

I guess switching blogs is less riskier than switching jobs. Anyway I had to take that risk of switching jobs in last month (12/2009) as I've joined WSO2 as a Senior Software Engineer. My very first job lasted only one and half years owing to various issues I had with the type of work I got during my first employment. However it was a good experience on some rare technologies like Search Engines and Indexing.. and not forgetting C++. Now.. the context has changed.. technologies has changed.. environment has changed... So I believe it's a whole new experience to me to work for WSO2 , which is a renowned Open Source SOA Company. These are my first few steps in the world of SOA and Web Services...