MOINC - The Future Web Services!!!

As Web services continue to become the dominant paradigm in the arena of distributed computing, more and more people around the world are starting to get interested in improving the performance and scalability achievable from Web services deployments. An enterprise grade Web services deployment must be high available and scalable in order for it to be useful to the clients and provide a competitive advantage for the service provider. Due to this reason it has become a must for the Web services middleware providers to support high availability and scalability via general techniques such as clustering.

Me and some of my colleagues recently started a venture to explore the potential of grid computing as a means of improving the availability and scalability of Web services deployments. Our plan is to design and develop a complete open source Java Web services deployment platform which makes use of grid computing as the basis for clustering. This exciting concept is a brain child of one of our lecturers at the Department of Computer Science and Engineering, Dr. Sanjiva Weerawarana, who also happens to be the chairman and CEO of WSO2. This research project focuses on not only improving the scalability of Web services deployments via grid computing but also putting the much wasted electrical energy to good use by getting idling computers to do some useful work.

We have named the project 'MOINC' which stands for Mora Open Infrastructure for Network Computing. (If you are confused what 'Mora' is all about it's a little nick name for the University of Moratuwa. 'Mora' also means shark in Sinhala.) So far we have managed to successfully complete the requirements gathering and design phases of this massive R&D effort. We have identified four components in our target platform and four groups of undergrads are working on implementing the components. The four components are;

• MOINC Server
• MOINC Client Agent
• MOINC Server Manager
• Thisara Communication Framework

You can learn more about our project and its four main components from our official website. You will also find links to our design documents, proposals, specifications and SVN repositories there. We recently released the 0.1-alpha version of the Thisara messaging framework which is one of the four components of the MOINC platform. You can download the binaries from our website too.

Google Chrome, Looking Good

It seems almost everybody is taking a strong liking into Google Chrome these days and almost everybody who has downloaded it seems to be appreciating it a lot. So I myself thought of giving Google Chrome a trial run. 

However I have to say that my first impression on Google Chrome was not a very good one mainly due to the fact that it’s only available for the Windows platform at the moment. I’m an open source fan and that makes me naturally dislike anything that won’t run on Linux out of the box. However I think I can forgive Google for that. I believe they just wanted to keep the things simple by focusing on one target platform since this is only a beta release. Also they probably wanted to get the maximum possible test coverage out of this release. In that case Windows is the only logical solution since whether we like it or not Windows still dominates the client side system software market. (and it will probably remain that way for a long time :-( )

Other than the above mentioned glitch my experience with Google Chrome has been a fairly good one. It’s easy to install and configure. I really like the wording and labeling convention used in Chrome. It’s simple and casual English that anybody can understand. Not a single technical word is used so that even someone who is browsing the Internet for the first time can easily get used to Google Chrome. Even the buttons that are usually rendered as ‘browse’ buttons in other browsers will be rendered as ‘choose file’ buttons. 

The user interfaces are pretty cool too. Chrome UI designers have clearly dumped the approaches taken by IE developers and Firefox developers to come up with their own style. It has no menu bars and no tool bars. All it has is the address bar with few more additional controls embedded into it. The address bar can be used to type in both URLs and search queries. One advantage of this organization is that it makes the browser’s main Window large so that the user can see more content without having to scroll much. But the problem is for someone who is so used to IE or Firefox, figuring out how to control the browser is going to be a bit of a pain.

In my opinion it has slightly better performance compared to Firefox-3 and IE-7. (well at least I feel that way) I have experienced frequent browser crashes with both IE-7 and Firefox-3. But I’m yet to experience that in Chrome. 

Perhaps the most enticing feature of Chrome is that every time a new tab is opened a new process is forked off by the browser. This way each tab gets its own set of resources. This will hopefully rectify most of the memory related issues experienced by other browsers. If you are a regular Firefox user you know that as we continue to open new tabs in Firefox the overall performance of the browser degrades significantly. This is because all the tabs have to share the same set of resource (memory in particular). By dedicating a separate process for each tab Google Chrome effectively deals with this issue.

I will continue to test Google Chrome in the days to come. I just started with Chrome and I will be in a better position to give a comprehensive feedback after another couple of weeks. Until then ‘good job Google’!

Lex It! Yacc It!

Lately I have been working a lot with the two legendary parser generator tools, ‘Lex’ and ‘Yacc’. (Well it’s actually ‘Flex’ and ‘Bison’ to be precise) To be honest I didn’t have any experience with Lex and Yacc two weeks back. But the two applications are so easy to learn and master that anyone could become an expert compiler developer in no time. Practically speaking one could start developing parsers and compilers without any prior knowledge on compiler theory or language parsing. All you need to get started is some experience in C programming. However I have to admit that some knowledge on regular expressions, context free grammars and push down automatons can make your life lot easier since that would help you better understand the syntax of the two configuration languages used by Lex and Yacc. 

Lex (or Flex) generates a C function called yylex which is capable of scanning and tokenizing a given input. The input to Lex primarily consists of regular expressions and C code segments to be executed on detection of strings that match the regular expression definitions. Yacc (or Bison) generates a C function called yyparse which accepts a sequence of tokens from yylex and parses them. The YACC input would include the productions of the language grammar and C code segments to be executed on application of the productions. 

It’s truly amazing how easy to develop parsers to accept complex languages with Lex and Yacc. The more I use it more I like it. The syntax of the configuration files are well structured and so easy to understand. I was so inspired by these two applications that I started developing my own command-line mathematics package for Unix/Linux systems. My plan is to develop something which is similar to the command interpreter that comes with MATLAB. I have already implemented support for executing simple mathematical expressions, trigonometric functions, logarithms and variables. I’m currently trying to implement the support for user defined functions. Once that is done I intend to implement support for matrix algebra and simple statistics.

The above sounds like a lot of work but thanks to Lex and Yacc I have to write only a very small amount of code. The two magic tools do the job by generating hundreds of lines of C code for me. Of course needless to say that developing something similar from the scratch would surely take months.

I’ve always wondered how come there are so many programming languages. But now I think I know the answer. It’s so freaking easy to develop parsers and compilers for a language with tools like Lex and Yacc. Once you have a language expressed in terms of a set of productions it takes only a few minutes to develop a fully functional compiler. So anyone can come up with an idea for a new language and turn it into reality in a flash. In fact I’m thinking about doing the same in the near future :-)

If you are like me and want to learn and master Lex and Yacc here is a cool reference guide. It helped me out a lot and I’m sure it will do the same for you.