Llovizna

Spring is here..

2013-05-06T15:48:00.003+05:30

[06/05/2013] Lisbon - Weeks 35 & 36: As usual stuff are getting warmer, lately. Both the weather as well as the Erasmus Life. Project deadlines reaching. May is a special month. In Sri Lanka, May comes with heavy showers. But it brings the spring flowers here, in Lisbon. Weather is changing.

[01/05/2013] Amidst the busy schedule, I was still able to have a day off, on the May day! We took a boat from Cais do Sodre to Cacilhas. From Cacilhas, we took a bus to Costa da Caparica, a magnificent beach town of Setubal district from the Almada neighbourhood, at the other end of the river. Finally, we took a bus to Lisbon - Arreiro, after enjoying(?!) the still-not-warm water of the beach. It is pretty interesting to see how the two sides of the river differ from each other, by the roads, architecture, and transportation. This was the first time I travelled across the 25th April bridge. Last time, it was over the Vasco da Gama bridge for Freeport.

Project deadlines are reaching. Hope we will get some time for a short break after the 10th of May, to enjoy the spring!

Thursday, 18th of April, 2013

2013-04-18T05:33:00.001+05:30

An attempt to make milk rice for the Sri Lankan New Year

It is interesting to see how the time is going too fast, and I realized many things have changed this year. We are almost finishing the first trimester of the year.

Weeks 32, 33, & 34 - I was updating Llovizna with fortnight (if not weekly) reports on my stay in Lisbon. However, the past few weeks were going pretty fast with the presentations, mid-evaluations, and other stuff, which made me forget the blog. I didn't fail to notice a considerable drop in the blog views this year, probably due to the infrequent blog posts, and even the posts are just becoming personal and deviating from the highly technical nature of Llovizna. I am still happy that I didn't let Llovizna starve without posts.

Sinhala Tamil New Year is the mostly celebrated Sri Lankan festival. I tried to create a milk rice for this, though I am not sure about its success, as I ate all of it myself. :D

Today, whilst doing the virtual execution project, I was thinking how the year 2013 is becoming yet another year of changes. The impact of this year is surely remarkable, and I hope this will become a highly effective year just like the years 2002, 2004, 2010, and 2012 for me. Lisbon is getting greener. As I walk towards ISCTE-IUL, I see new leaves appearing on the trees fresh and young. I walk down the streets without the winter clothes. Spring is here. I feel, I will remember this day for many of the upcoming years.

Before Implementing Garbage Collector Algorithms for MMTk

2013-04-02T16:24:00.001+05:30

Jikes RVM comes bundled with multiple plans, allowing us to build it with a preferred garbage collection algorithm, either concurrent such as concurrent mark and sweep (CMS), or the stop the world implementations that are not concurrent. When implementing a concurrent garbage collector, it is recommended to benchmark it against CMS collector, as it is the complete concurrent collector in production, where all the other collectors operate in the stop-the-world manner, where the program threads are halted.

Testing whether a new collector will work with the current build is a good starting point before actually starting with the coding.

[1]. First build Jikes RVM, with MarkSweep garbage collector

bin/buildit -j $JAVA_HOME localhost BaseBase MarkSweep

[2]. Test the GC

bin/buildit -j $JAVA_HOME localhost -t gctest BaseBase MarkSweep

[3]. Dummy Compressor GC.

Before testing the real implementation of the new GC algorithm Compressor, we will test that it will work.

Copy the package org.mmtk.plan.marksweep in MMTk/src as org.mmtk.plan.compressor and rename the package names accordingly.

In build/configs, copy BaseBaseMarkSweep.properties as BaseBaseCompressor.properties

[4]. Test the dummy compressor GC
bin/buildit -j $JAVA_HOME localhost -t gctest BaseBase Compressor

You should be able to see the [echo] ... SUCCESS as seen above in [2], upon a successful build. Now this is time to check the implementation of the new algorithm.

Jikes RVM comes bundled with multiple test cases for benchmark suites and test benches, which can be found at testing/tests.
For example, SPECjbb2000, SPECjbb2005, SPECjvm98, SPECjvm2008, and mmtk-harness.

[5]. To run the dacapo (free and open source; download) (Dacapo is specifically used for the client side testing of the rvm), SPECjvm2008 (free download), and SPECjbb2005 tests against a production build or a BaseBase Compressor build,
bin/buildit -j $JAVA_HOME localhost -t dacapo -t SPECjvm2008 -t SPECjbb2005 production
or
bin/buildit -j $JAVA_HOME localhost -t dacapo BaseBase Compressor

[6] Benchmarking with DaCapo.
pradeeban@llovizna:~/jikesrvm/dist/BaseBaseMarkSweep_x86_64-linux$ ./rvm -jar dacapo.jar jython
*sys-package-mgr*: processing new jar, '/home/pradeeban/jikesrvm/dist/BaseBaseMarkSweep_x86_64-linux/dacapo.jar'
*sys-package-mgr*: processing new jar, '/home/pradeeban/jikesrvm/dist/BaseBaseMarkSweep_x86_64-linux/jksvm.jar'
*sys-package-mgr*: processing new jar, '/home/pradeeban/jikesrvm/dist/BaseBaseMarkSweep_x86_64-linux/rvmrt.jar'
===== DaCapo jython starting =====
-------------------------------------------------------------------------------
PYBENCH 2.0
-------------------------------------------------------------------------------
* using Python 2.2a1
* Python version doesn't support garbage collection
* system check interval set to maximum: 2147483647
* using timer: time.time

Calibrating tests. Please wait...

Running 1 round(s) of the suite at warp factor 20:

* Round 1 done in 61.664 seconds.

-------------------------------------------------------------------------------
Benchmark: 2013-04-06 12:13:24
-------------------------------------------------------------------------------

    Rounds: 1
    Warp:   20
    Timer: time.time

Test                             minimum average operation overhead
-------------------------------------------------------------------------------
          BuiltinFunctionCalls:    479ms    479ms    1.88us    0.000ms
           BuiltinMethodLookup:    941ms    941ms    1.79us    0.000ms
                 CompareFloats:    256ms    256ms    0.43us    0.000ms
         CompareFloatsIntegers:    199ms    199ms    0.44us    0.000ms
               CompareIntegers:    371ms    371ms    0.41us    0.000ms
        CompareInternedStrings:    510ms    510ms    0.68us    0.000ms
                  CompareLongs:    256ms    256ms    0.49us    0.000ms
                CompareStrings:    371ms    371ms    0.74us    0.000ms
                CompareUnicode:    278ms    278ms    0.74us    0.000ms
                 ConcatStrings:   6144ms   6144ms   24.58us    0.000ms
                 ConcatUnicode:   4123ms   4123ms   27.49us    0.000ms
               CreateInstances:   1094ms   1094ms   19.54us    0.000ms
            CreateNewInstances:   2056ms   2056ms   48.95us    0.000ms
       CreateStringsWithConcat:   4112ms   4112ms    8.22us    0.000ms
       CreateUnicodeWithConcat:   1884ms   1884ms    9.42us    0.000ms
                  DictCreation:   1532ms   1532ms    7.66us    0.000ms
             DictWithFloatKeys:    475ms    475ms    1.06us    0.000ms
           DictWithIntegerKeys:    468ms    468ms    0.78us    0.000ms
            DictWithStringKeys:    266ms    266ms    0.44us    0.000ms
                      ForLoops:    945ms    945ms   75.60us    0.000ms
                    IfThenElse:    397ms    397ms    0.59us    0.000ms
                   ListSlicing:    956ms    956ms 136.57us    0.000ms
                NestedForLoops:   1024ms   1024ms    1.37us    0.000ms
          NormalClassAttribute:    911ms    911ms    1.52us    0.000ms
       NormalInstanceAttribute:    453ms    453ms    0.76us    0.000ms
           PythonFunctionCalls:   1343ms   1343ms    8.14us    0.000ms
             PythonMethodCalls:   2451ms   2451ms   21.79us    0.000ms
                     Recursion:   1091ms   1091ms   43.64us    0.000ms
                  SecondImport:   1009ms   1009ms   20.18us    0.000ms
           SecondPackageImport:   1030ms   1030ms   20.60us    0.000ms
         SecondSubmoduleImport:   1509ms   1509ms   30.18us    0.000ms
       SimpleComplexArithmetic:   1651ms   1651ms    3.75us    0.000ms
        SimpleDictManipulation:    612ms    612ms    1.02us    0.000ms
         SimpleFloatArithmetic:    991ms    991ms    1.50us    0.000ms
      SimpleIntFloatArithmetic:    351ms    351ms    0.53us    0.000ms
       SimpleIntegerArithmetic:    350ms    350ms    0.53us    0.000ms
        SimpleListManipulation:    440ms    440ms    0.75us    0.000ms
          SimpleLongArithmetic:    931ms    931ms    2.82us    0.000ms
                    SmallLists:   1263ms   1263ms    3.71us    0.000ms
                   SmallTuples:   3198ms   3198ms   11.84us    0.000ms
         SpecialClassAttribute:    908ms    908ms    1.51us    0.000ms
      SpecialInstanceAttribute:    456ms    456ms    0.76us    0.000ms
                StringMappings:   2341ms   2341ms   18.58us    0.000ms
              StringPredicates:    825ms    825ms    2.36us    0.000ms
                 StringSlicing:   1803ms   1803ms    6.44us    0.000ms
                     TryExcept:     40ms     40ms    0.04us    0.000ms
                TryRaiseExcept:   2113ms   2113ms   66.03us    0.000ms
                  TupleSlicing:   1951ms   1951ms   14.86us    0.000ms
               UnicodeMappings:    942ms    942ms   52.33us    0.000ms
             UnicodePredicates:    705ms    705ms    2.61us    0.000ms
                UnicodeSlicing:    859ms    859ms    3.51us    0.000ms
-------------------------------------------------------------------------------
Totals:                          61664ms 61664ms

===== DaCapo jython PASSED in 66736 msec =====

MMTk mechanisms, policies, and plans

2013-03-31T19:47:00.001+05:30

Class Diagram: MMTk Policies

MMTk is a flexible memory management utility written using java, for Jikes RVM. It is also ported to Rotor - the Microsoft's open C# runtime. Key Compositional Elements in MMTk are utilities, policies, and plans.

Bootstrapping
Jikes is meta-circular, as it is written in Java, the language it interprets as a JVM. Here, the functionality of the parent interpreter is applied directly to the source code being interpreted, without any additional implementation. Hence it requires a bootstrap VM to run upon, to create a boot image. However, it doesn't run on an external JVM. Rather, a small boot image runner written using C is responsible for loading the image files at run time, and it transfers the control to the native VM code that runs on the host [1].

Interruptibility

Compiler pragmas are used by MMTk to control the inlining and interruptibility, and scoped across methods and classes, where more specific pragma scopes such as method pragmas override the broader ones such as class pragmas. Classes annotated @Uninterruptible make the class uninterruptible. If most of the methods in a class are uninterruptible, annotating the class as uninterruptible is reasonable and preferred. All the policies and plans have the unintteruptible classes.

1) Mechanisms (utility)
1. Bump pointer allocation
2. Free list allocation
3. Large object allocation
4. Finalization

2) Policies (policy)
Spaces are contiguous regions of virtual memory, that is managed by a single policy. MMTk maps policies to spaces. In an address space, any given policy can manage multiple spaces.

Policies are implemented following the local/global pattern, and named XXXSpace and XXXLocal.
1. Copying Collector - CopySpace extends Space | CopyLocal extends BumpPointer

Class Diagram: MMTk Plans

2. Explicitly Managed Collector - ExplicitFreeListSpace extends SegregatedFreeListSpace | ExplicitFreeListLocal extends SegregatedFreeListLocal
3. ExplicitLargeObjectSpace extends BaseLargeObjectSpace |
4. Immortal Collector - ImmortalSpace extends Space | ImmortalLocal extends BumpPointer
5. Treadmill Collector - LargeObjectSpace extends BaseLargeObjectSpace | LargeObjectLocal extends LargeObjectAllocator
6. Mark-Compact Collector (MarkCompactCollector) - MarkCompactSpace extends Space | MarkCompactLocal extends BumpPointer
7. Mark-Sweep Collector - MarkSweepSpace extends SegregatedFreeListSpace | MarkSweepLocal extends SegregatedFreeListLocal
8. RawPageSpace extends Space
9. SegregatedFreeListSpace extends Space

Each instance of a policy space maps to a single virtual memory space, with P instances of the local class attached, where the collector is P-way parallel.

3) Plans (plan)
It is the highest level of composition, as it composes policies to build a memory management algorithm.
1. CMS (concurrent.marksweep)
2. CopyMS (copyms)
3. GenCopy (generational.copying)
4. GenMS (generational.marksweep)
5. GenImmix (generational.immix)
6. MC (markcompact)
7. MS (marksweep)
8. NoGC (Global state of a simple allocator without a collector)
9. RC (refcount.fullheap)
10. GenRC (refcount.generational)
11. SS (semispace)
12. GCTrace (semispace.gctrace)
13. UsePrimitiveWriteBarriers (semispace.usePrimitiveWriteBarriers)
14. StickyImmix (stickyimmix)
15. StickyMS (stickyms)

Lisbon - Weeks 30 & 31

2013-03-30T18:51:00.000+05:30

Cooking in Lisboa!

[30/03/2013] - This week comes with the Easter vacation, which was not really a vacation, as we had projects to be completed for the checkpoint.

[29/03/2012] For the past few days this week, I have been cooking myself, and interestingly, it came out pretty well. Within 3 days since I started cooking, I have even started to cook without a recipe. So much win, and yet another mission successful of the year 2013. There is a Nepal restaurant (Restaurante Kathmandu) close to my apartment which has a good Chicken mango curry. So I decided to try and cook it.

The mango recipe of Fish or Chicken are pretty simple. First you cook Chicken in Coconut milk without adding spices (no curry powder or chilli powder), except onion, garlic, turmeric, ginger etc, and eventually start adding Mango milkshake, as the chicken is cooked. Mango milkshake was made with one mango, two cups of yoghurt, some milk, a little salt, and a tablespoon lime juice as the ingredients. The final flavor of the sauce is mostly yummy mango. Cooking with coconut milk was just to cook the chicken long enough, without spoiling the mango flavor. So the only difference is, replacing the chilli powder/curry powder combination with the mango milkshake. Make sure the mango milkshake is not burnt. It easily gets burnt and sticks to the pan, as it is sugar. Adding it later to the pan helps avoiding this, while preserving the sweetness. I tried banana apple milkshake too. But Mango seems better. You should give a try to mango.

Obidos

Fish Mango curry, Leaves curry, Carrot mango curry, and Rice in the image above. It was a huge success for the 3rd night of my cooking. Fish mango curry was a dish inspired from the Chicken mango of the Restaurante Kathmandu. However, I guess, I am the first to invent Fish Mango in this way.. :D Recipe (my own recipe.. haha..)

[27/03/2013] - We paid a quick visit to Obidos. It is a lovely neighbourhood. Regular bus services are available from Campo Grande of Lisboa, operated by Rodo Tejo. (Return trip, 2* 7.55 Euro).

[18/03/2013] - Freeport is a huge open shopping centre (centro comercial) situated in Alcochete, across the Tagus river, which can be reached by the bus 431 from Oriente, and many other means, pretty easily. The shopping centre was not that interesting, though it is considered to be the largest outlet in Europe. However the bus travel over the Vasco da gama bridge, which is considered the longest bridge in the Europe, was interesting.

3 months have already passed this year (almost!). Happiness, Excitement, Craziness, Sadness, Depression, and Stupidity - everything that comes in a mixture, slightly overdose, and that is my year 2013.

Lisbon - Week29

2013-03-14T07:29:00.000+05:30

A nightly walk at Entre Campos

[14/03/2013] The second semester is getting hotter. ;) We have received the project specifications for 3 out of the 4 modules. We have already submitted the project proposals for 2 of them. We are researching Jikes RVM for the Virtual Execution Environments module.

[13/03/2013] - These days, I was busy buying flight tickets. It was a good learning experience. I was not aware of the clause, "LOW COST FARE. CANNOT BE CHANGED OR CANCELLED" and this means, we can not change a flight or cancel it. I confirmed it from the two airlines concerned, and they mentioned that this can be changed only by the travel agents (eDreams), but the travel agent eDreams policy doesn't let changing the reservation of the "Economy Restricted" tickets. I find it interesting. I should note that TAP Portugal outlet at Marques De Pombal officers were pretty much helpful.

I am enjoying the nightly walks in Lisbon. 2013 is different. I should start writing a blog post on how the year 2013 is remarkably different. :)

Lisbon - Weeks 27 & 28

2013-03-10T05:44:00.000+05:30

From Cabo Ruivo to Parque das Nações..

[07/03/2013] - EMDC 2013 batch now received the official invitations, and they are being added to the Facebook group of EMDC. The group is getting more and more active. The excitement of the students remind me the early 2012, when I was expecting the day to join EMDC - good old days. ;)

[05/03/2013] - I have been elected as an Erasmus Mundus Course Representative for the EMDC, for the year 2013. Click HERE to view the list of elected representatives for 128 programmes!

[27/02/2013] - I bought a Sony Xperia J from fnac, and realized it was locked by Vodafone. It keeps asking "SIM Network Unlock PIN", when I start the phone with the MOCHE SIM, instead of the Vodafone SIM that came bundled with the phone, and without it, it was not working with the MOCHE SIM.

From Spain to Portugal - A boat of descubriter.

I visited fnac and asked whether they could unlock my phone, when I realized that I couldn't unlock it myself or via online services, without paying for their service. Fnac pointed me out that I should contact the service providers to unlock the phone. I reached Vodafone and paid 47.47 Euros to unlock the phone, which included the discount due to the bond with the service provider and the service charge + tax.

I was told I will be sent an sms with the unlock code, in 3 days, which is supposed to be a Saturday. I didn't get any. Assuming they may not work in weekends, I waited further, and eventually waited till the Monday. I still didn't get it! So I reached to them again on the Tuesday, where they unlocked my phone, by entering the unlock code themselves. Never mind, I got it sorted out, at least! :)

[22/02/2013] - Parque das Nações never fails to amuse me. It is full of interesting restaurants, seagulls, and cold wind. The small port of Parque das Nações provides a stay for the mini boats. Parque das Nações surely is a highlight of my year 2013.

Building Jikes RVM on Ubuntu 12.04 / 64 bit from source

2013-03-03T10:04:00.003+05:30

Jikes RVM is a research virtual machine, built using Java. Building Jikes RVM from the source (trunk) is pretty interesting.

Installing the pre-requisites
Mercurial is the version control system of Jikes RVM. (To learn the basics of Mercurial, please refer to this article.) Jikes RVM is built using Apache Ant. Make sure to install these.
sudo apt-get install mercurial ant

Install gcc, g++, gcc-multilib, and g++-multilib
sudo apt-get install gcc-multilib g++-multilib

Checking out the source
Checkout the source code of Jikes RVM.
hg clone http://hg.code.sourceforge.net/p/jikesrvm/code jikesrvm

Updating the source
If you have already checked out the source code sometime back, you may have to update it to reflect the later changes.
To view the information of the working directory, such as the version number, from the root directory,
hg log -l1

To update,
hg pull

hg update

Building using Ant
Find the target architecture of your system.
uname -m
x86_64

Build using Ant from jikesrvm (the root directory of Jikes RVM).
ant -Dconfig.name=prototype -Dhost.name=x86_64-linux -Dtarget.name=x86_64-linux

Here,
1) host.name and target.name entries should match the names of the properties files present in the directory jikesrvm/build/hosts (without the suffix, .properties).

2) config.name entry should match the names of the properties files present in the directory jikesrvm/build/configs (without the suffix, .properties).

You may alternatively build Jikes using the buildit tool that is included in the project.
bin/buildit -j $JAVA_HOME localhost production

Common Exceptions
1) You may encounter the below exceptions, if you have 32-bit GTK libraries installed on a 64-bit machine.
[exec] checking for X... no
[exec] configure: error: GTK+ peers requested but no X library available

BUILD FAILED
/home/pradeeban/jikesrvm/build.xml:266: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build.xml:272: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/classpath.xml:305: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/base.xml:70: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/base.xml:76: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/classpath.xml:254: exec returned: 1

Passing the flag -Dcp.enable.gtk-peer="--disable-gtk-peer" will fix this issue.

ant -Dconfig.name=prototype -Dhost.name=x86_64-linux -Dtarget.name=x86_64-linux -Dcp.enable.gtk-peer="--disable-gtk-peer"

2) You may encounter the below exceptions, if you miss gcc-multilib and g++-multilib in your system.

build:
[exec] checking build system type... Invalid configuration `x86_64-unknown-linux-': machine `x86_64-unknown-linux' not recognized
[exec] configure: error: /bin/bash ./config.sub x86_64-unknown-linux- failed

BUILD FAILED
/home/pradeeban/jikesrvm/build.xml:266: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build.xml:272: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/classpath.xml:305: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/base.xml:70: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/base.xml:76: The following error occurred while executing this line:
/home/pradeeban/jikesrvm/build/components/classpath.xml:254: exec returned: 1
Running Jikes RVM
Once built, you will find the complete rvm runtime directory at ${dist.dir}/${config.name}_${target.name} (For me, it was dist/prototype_x86_64-linux, as I built with 'prototype' configuration). Now you should be able to run the rvm from the directory. A Java class can be run as below.

javac HelloWorld.java
./rvm HelloWorld

Feelings of Erasmus Mundus

2013-02-21T04:59:00.001+05:30

Baixa-Chiado Metro Station, a remarkable one for Erasmus Students

Week 26

[20/02/2013] - Since we don't have the lectures in Taguspark campus, we don't have to use the IST shuttle anymore. This saves us a lot of time this semester, compared to the last. However, we miss the good times we had at Taguspark, specially the lunch time together. I used to wake up at 5.30 a.m to catch the 7.15 a.m shuttle on Mondays. This semester, I wake up at 7.30 a.m, the earliest. More time to sleep!

6 months

Today we did our Mobile Computing presentation. This was the first team effort of Team XPD (Xiao Chen, Pradeeban Kathiravelu, and Dipesh Dugar Mitthalal). Now, I am having a break with some music, and decided to blog on the feelings of Erasmus Mundus, which was in my to-blog list for quite a long time. Interestingly, today it is exactly 6 months since I left home and my country, for my masters!

Feelings of Erasmus Mundus

My apartment - a usual meeting spot for us!

Erasmus Mundus is surely one of the best (if not the best) decisions that we all have made. We all came to Lisbon as strangers. I had interest in exploring Lisbon, but no real attachment to it.

Eventually!

Things started to change eventually. The support and helping hand of the locals surely made a positive impact on me. In my opinion, Portuguese are very friendly people. We, all the EMDC students became good friends. It felt good to be a student, after a break, as I became a student after spending two years working in a company. As Erasmus Mundus students, we had a huge opportunity to meet other mobility students, who follow Erasmus, Erasmus Mundus, BRAZIL, and similar programs. Meeting points like Bairro Alto and specifically the Erasmus Corner, became regular places of visit. Moreover, the cultural diversity made our relationships more interesting and spicy! ;)

Fresher Winds

Nightly walks over Lisbon neighbourhoods!

It was like a rebirth, where we started to learn and earn everything fresh - new courses, new friends, new people, and new experiences. We came to Lisbon, almost with an empty hand and mind, with nothing but hope and expectations. We started to earn people and knowledge. Our relationships are interesting and non-trivial. Erasmus Mundus experience has written many new interesting pages in our life.

Level - up

Erasmus Mundus experience was a level-up. We learned about people and culture. Tried different dishes. A few phrases from each language! From what I learned and experienced, I would recommend every student to study abroad, as an exchange student, or as a graduate student abroad, at least once in their life. The aspects of life we learned during the Erasmus Mundus is much richer than the technological knowledge we have gathered so far during our stay. Balancing the social life and studies without getting too distracted, enjoying the new environment without compromising our unique values and believes, accepting different view points and learning from them, broadening the horizon, were a few interesting challenges the students face.

Walking from Santos to Cais do Sodre

World is not that small. :(
A few friends have already left us and returned to their home countries, as they have completed their study. We already miss them. They have surely left a strong foot print in our minds, which will never fade away. I am sure, I will miss Lisbon when I go to Stockholm next semester, as much as I missed my country when I left it last year. Probably, even more! Lisbon has surely become a second home to me, during the stay of the 6 months. The interesting people we met here from different parts of the world - I am not sure how effective we will be in communication or how much will we be in touch, after we departed. The world is still not that small, and I don't think the online or electronic communication is strong enough to express the human feelings, or replace the face-to-face communications. Quoting our P2P professor, once more. "Human nature: It is difficult to understand."

I just wish everyone of you will be with me, forever!

EMDC Winter Event 2013

2013-02-19T00:44:00.000+05:30

Picturesque Segovia

Weeks 24 & 25

[13/02/2013] - The last two weeks of the vacation were spent at Spain (Photos), in Madrid, Segovia, Barcelona, Nuria, and Sitges.

2nd Semester!
The second semester started on the 13th. The new semester has an interesting time table. We have lectures on Tuesdays, Wednesdays, and Thursdays. Finally, weekend has become longer than the weekdays! Like the first semester, this semester too we have 4 modules - Middleware for Distributed Internet Applications (PADI764), Fault-Tolerant Distributed Systems (SDTF64), Virtual Execution Environments (AVExe364), and Mobile Computing (CMov764). We already have formed the groups for the projects, and are ready for yet another interesting episode.

Sitges Carnival was full of partiers parading!

Trip to Spain

EMDC Winter Event (6th - 8th, Feb 2013) was held at Vall de Núria. We planned a Spain trip (3rd - 11th, Feb 2013) along with the winter Event, covering Madrid and Barcelona, along with the neighbourhood, including Segovia and Sitges. Our flight itinerary was, Lisbon -> Madrid -> Barcelona -> Lisbon.

We spent the first few days in Madrid (3rd - 5th, Feb). We were at Segovia on the 5th of Feb. Segovia is a silent and charming neighbourhood, with a wonderful architecture, including the Gothic Cathedral of Segovia and Aqueduct of Segovia. We went to Barcelona on the 5th night, and had a brief meeting at UPC, on the 6th.

La Vall de Núria

Heavenly Nuria - This is where we stayed!

Then we moved to Nuria, where we enjoyed the snow, skiing, food, games, and presentations. It was an awesome experience, and the special thanks goes to the professors who organized this event pretty well, and the industry experts and the senior students, who shared their knowledge and experience with us. Travelling by the rack train that connects Nuria to Ribes was a remarkable experience. The change in the landscape and the climate was obvious. Mountains covered with snow, and heavy snow was the norm in Nuria.

We noticed that French border is just in a walking distance, from where we are right now. Snow, and -10°c. (Feels like -24°c). However, in winter, I don't think it's even possible in this heavy snow, except for those who are into adventures.

The Erasmus Mundus EMDC 2012 students from IST and UPC introduced themselves with two presentations. The EMDC-IST introductory presentation introduced all 8 of us.

On the 8th, we returned to Barcelona, where we stayed for the rest of the days, visiting CosmoCaixa Barcelona (formerly known as the science museum of Barcelona), Park Guell, and the other attractions around. Interestingly, we also got the chance to enjoy the carnival at Sitges, on the 10th of February. I enjoyed Spain. However, my preference is still Lisbon/Portugal. The comforting weather, availability of varieties of stylish food, the lovely people, or just my personal preference. Probably, I am just addicted to Lisbon.

Lisbon - Weeks 22 & 23

2013-01-27T23:32:00.000+05:30

Fátima

[30/01/2013] - Vacation! This fortnight was full of eating out, travels, and shopping.

[27/01/2013] Two of my batch mates were in Lisbon during this week, and it was really nice to have some Sri Lankans around, after a long time, and discuss some good old memories!

[23/01/2013] - We paid a visit to Leiria-Fátima, by Rede Express bus service, which starts from Sete-Rios (Metro Station - Jardim Zoologico). Fatima is a religious place for Catholics, with the church of Our Lady of Fatima.

Seagulls in Parque das Nações

One month of 2013 is going to finish.. :-o 2013 is surely becoming the most eventful year ever. Successful exams, followed by a vacation, of which two weeks have already gone, like a beautiful dream - with joyful, interesting, exciting, as well as sad moments. I guess, I love Lisboa (and its food, drinks, the shades of the mild winter evenings it has to offer, and the lovely people..).. ♥

Feeding seagulls in Parque das Nações (Parque Expo), watching movies, metro journeys, travel by tram no.28, and trying different restaurants by Parque Expo were remarkable. I will surely miss my friends, when they start returning to their countries, finishing their studies in Lisbon.

Lisbon - Week21

2013-01-18T02:52:00.000+05:30

[17/01/2013] - Exams have completed, and we are also getting the results! Final results for 2 of the 3 modules are already out. The results are highly positive. :) Now vacation period! Movies, shopping, travels, and eating out!

Expectation: 30 mins technical call. Reality: 5 mins sales call.. AWW yeah.. This is 2013.. :P Still was glad to receive a long technical document, via email marked "CONFIDENTIAL", after quite a long time. :D

Lisbon - Week20

2013-01-09T17:49:00.001+05:30

IST is full of oranges these days!

[09/01/2013] Exams have started, and are going pretty well. Done with Security and Parallel Computing, and remaining is cloud computing.
[08/01/2013] In the mean time, had a long shopping at Colombo, Centro Comercial. Lisbon is a good place to do some serious shopping.

A colourful new year

2013-01-01T19:42:00.000+05:30

2013 just started with colours and style, as an energetic year. 2012 was the most successful as well as an important year for me. I expect 2013 to be more interesting. Very happy new year everyone.

Lisbon - Week19

[01/01/2013] - The count down for new year and the fireworks at Praca do Comercio was nice. Now time to get back to studies, for the upcoming exams next week.. :)

Kitteh Roulette
The Internet is full of cat people. I found an interesting site named KittehRoulette, which gathers a few interesting YouTube videos of cats, and shows them randomly. If you are a cat person, I would recommend you to have a look in this new year. ;) You will keep clicking "Next Kitteh!"

A few things that made my 2012 interesting..

2012-12-29T20:37:00.000+05:30

It has become my regular practice to write a wrap-up blog post each year. Time has come to say good bye to the year 2012. I was keeping my blog readers updated on the with regular updates. Year 2012 - a year of changes summarizes the first two trimesters of the year. In a following post, I thanked all the wonderful people who made my 2012 remarkable. This year was truly remarkable, and probably it was one of the 3 best years so far (the other two were years 2010 and 2004). I foresee a much more interesting year 2013.

Now time to look into some random things that made me 2012 a unique year. This is an unordered list.

1. Broken resolutions - Yes, those resolutions which rarely works. Not to stay up too late, not to spend much time on the Internet, .. these resolutions! :P

2. Successful goals - Surprisingly, 2012 turned to be a very successful year. It didn't start pretty well, to be honest. Learned more realities of life throughout the year. :D

3. Movies - Oh.. too many of them this year.. :D

4. Nightly walks - I always enjoyed a long walk, in the nights. ^ ^

5. Busy days getting the documents ready for the Portuguese visa. It was not fun. However, now all it gives is nice memories.

6. Pahar Ganj - When I said I am going to stay in a place called Pahar Ganj during my visit to India, some guys who are from New Delhi were scaring me saying Pahar Ganj is a dangerous place. I myself noticed that the place is dodgy, as an over-crowded place next to the central railway station. Staying there for a few days gave me a more insight of New Delhi.

7. Trip by HoHo bus in New Delhi - It was interesting (in a strange way) to travel alone to tourist attractions, such as Qutub Minar.

8. Three-wheeler negotiations in New Delhi - New Delhi by tuk-tuk was fun!

9. Exploring Colombo - Sometimes we don't really get the chance to explore the city that we live in. It was this year, when I really explored more of my city. :D

10. Random Shoppings in Colombo city!

11. Summer in Lisbon - Summer experience in Lisbon is really great.

12. Yellow bus travel in Lisbon - "Yellow bus" is a convenient way to explore Lisbon, in 48 hours, for 25 Euros. Visited many interesting places such as Lisboa Oceanario.

13. Shuttle travels to Taguspark campus!

14. Lunch at Taguspark canteen.

15. Dinner for 4.45 Euro at "Acucar & Canela".

16. My weekly blog posts on my stay here in Lisbon. Interestingly, the blog views got to a peak in the month of October. Moments with Twitter.. and Moments with Twitter - II became two of the mostly viewed posts, all time.

17. Living away from home and the country for the first time.

18. Nights at Bairro Alto and Cais do Sodre.

19. Group discussions for P2P exams!

20. Getting soaked in the wild rainy days at New Delhi during the second visit.

21. Gurudwara Bangla Sahib. Going to a temple of another faith that I was never aware of, turns to be interesting, like exploring a new world. This year, I went to many places of worship, of different faiths, including Central Mosque of Lisbon.

22. Visit to Munneswaram and the other surrounding Hindu temples. It felt great to have such a religious trip with family, after a long time, without much preparation.

23. Beach Wadiya of Wellawatte. Never mind the big fat rat.. :D

24. Emirates! I like the airlines, and Dubai Airport. This was not my first time though.

25. Letters from KTH - It was surely one of the highlights of the year. Letters regarding EMDC was always promising and made me smile big.

26. GSoC Awareness sessions all over the island. We did it big for GSoC 2012. More evangelization!

27. Optimism - Not that 2012 was full of good events. It had its own share of negative events and depressing moments. I feel, it was me being optimistic, made me take some brave decisions to withstand the currents, which eventually turned as the right decisions. :-)

28. Crazy friends - I am surrounded by them here. So no comments on this right now. :D

29. Portuguese classes. This one. :D I rarely did the homeworks. Probably, I should have put more effort. However, we have completed the Portuguese Level-1 now. :)

30. Being a student once more, after two years. Makes me feel younger! EMDC, IST, and Lisbon - It is a cool combination.. :D

We are going to Madrid, Barcelona, and Nuria in Spain the coming February for the EMDC winter event. Apart from this, I have plans to visit home next year, and also a short trip to South India, may be. Finally to KTH, Stockholm for the second year. 2013 seems more promising.

If you are really bored, you may also read the blog post on the year 2011. :D

Lisbon - Week18

2012-12-29T17:59:00.000+05:30

[29/12/2012] - The festival season, and Lisbon is celebrating. And now we feel the need to start studying for the upcoming exams, which commence by the 7th of January, next year. Exams - a great way to start the new year. We were still spending time going to shopping centers (Colombo, El Corte Ingles, and Centro Vasco da Gama) and watching movies.. :D

oh, and time to welcome the year 2013 now. :-)

Lisbon - Week17

2012-12-23T02:05:00.002+05:30

[22/12/2012] - Lisbon is getting into the festival season. We are finally having the Christmas break. Our exams start on the 7th of January. We have got the time table for the second semester already. The below modules will probably be the subjects for the next semester.

SDTF64 - Fault-Tolerant Distributed Systems

PADI764 - Middleware for Distributed Internet Applications
CMov764 - Mobile Computing

AVExe364 - Virtual Execution Environments

[21/12/2012] - I got the residence permit from SEF. We also have already bought the flight tickets to Madrid and Barcelona, for the EMDC winter event 2013.

[20/12/2012] - We are done with all the project demos, discussions, as well as the Security presentation on SeCrawler, which is a role-aware Secured Crawler, based on Crawler4j library.

YaCy Introductory presentation for P2P module

2012-12-14T17:20:00.000+05:30

Lisbon - Week16

[14/12/2012] - One of the busiest days. We submitted 3 final projects today, of Cloud Computing, P2P, and Security modules. You may have a look at the project.

[10/12/2012] Today we did an introductory presentation to the YaCy Decentralized Web Search - The Peer-to-Peer Search Engine, for the P2P module. The presentation we did is given below, for your reference.

Lisbon - Week15

2012-12-08T18:52:00.002+05:30

[08/12/2012] - The project deadlines are approaching the coming week. Everyone is getting busier. A few interesting events did occur during this time span.

[07/08/2012] - Tivemos o exame de português hoje. Eu estou contente que eu não desisti. Muito graças ao nosso professora por seus cuidados. I feel a bit guilty of not putting enough effort on learning Portuguese so far. I have loads of Portuguese speaking friends - I speak in English with all of them, so far. :)

[05/12/2012] - We get a student visa for 3 months, when we fly to Portugal. However, we are supposed to be present for an interview at SEF to obtain a residence card, usually covers a period of a year, for the Erasmus Mundus students, as we are going to study here for a year. SEF can be reached by metro. From the metro station Porque, turn right (when facing away from the entrance) and walk to #20. The interviews start at 8.30. I reached SEF by 8.20 and had to stay for 1.5 hours to complete the interview. It is better to reach around 8 am to be the first in the queue, and leave early.

Documents to take to SEF (information provided by IST)

1. Passport;

2. Proof of Residency;

One way do make proof of Residency

I. Declaration passed by your landlord;

II. A copy of the identity card from your landlord (SEF needs to check if the signature on the declaration passed by our landlord is the same);

III. A copy of the deed to the house (For SEF to check if the house is really the propriety of the person who is passing the declaration).

Other way do make proof of Residency

Certificate of Residence passed by the parish council (you landlord will assist you in doing this.

If you are in a residence

You must tell me in which one so I can include it in the declaration, therefore you don’t need to do the steps before described

3. Proof of means of livelihood

If you have Scholarship, the documents that prove you are receiving it.

If not, a copy of your bank account

4. Declaration elaborated by your institution (A formal letter/document provided by IST, in our case.)

5. A proof that you have health insurance

Lisbon - Week14

2012-12-02T18:48:00.000+05:30

[01/12/2012] - We are getting closer to the final project deadlines, as the month of December reaches. I was bored and needed a change. Hence visited Colombo, Centro Comercial (metro station is Colegio Militar), bought Nexus7 tablet from Worten, and came back home. :)

Pensão Amor, which used to be a strip club at the former red light district of Cais do Sodré, in the historic times, is now a regular bar and a tourist attraction of Cais do Sodré, selling quality drinks as a bar. However, the price is simply thrice the amount than that you would find in the neighbourhood. Interestingly, it is crowded as it still holds the images and architectural marvels of its past pride. Check their website for some old live cams captured on the bar and the neighbourhood. We paid a quick visit to this place.

Google Code-In 2012

2012-11-24T20:17:00.001+05:30

I am mentoring for GCI for Haiku for the second time this year. This presentation is based on my experience as a mentor for Haiku in Google Code-In 2011. Hence the examples used in this presentation are mostly from Haiku. I hope, this presentation will be useful to any student as an introduction to Google Code-In.

Please note that this year the code-in rules are slightly changed.

Lisbon - Weeks 12 & 13

2012-11-20T05:40:00.001+05:30

[20/11/2012] 3 months since I left Sri Lanka. We celebrated Deepawali in Lisbon, the 13th of November, at the Radha Krishna temple, followed by an Indian dinner at the temple. It was interesting to represent Sri Lanka in the International Day at the IST Taguspark, the 19th of November.

As you see above, my presentation is too large (137 MB) to embed as a google doc. Still you may download it. :D

Tropical the island breeze.. All of nature, wild and free.. This is where I long to be.. La isla bonita..

Optimism is the selection of the nature

2012-11-07T03:20:00.000+05:30

Lisbon - Week11

[06/11/2012] We got the Amazon accounts and now time to do some experiments on them. Reading is a trap, and it takes time. Mastering Linear Algebra in 10 Days: Astounding Experiments in Ultra-Learning seems to be a promising read. I myself feel the time to accelerate.

Optimism

Being optimistic is the natural choice. We usually worry more about future events, than the past. I usually explain: Say we were worried whether the event X will be favorable to us. We have two possible results. Either X is finally favorable to us, or it is not. If it is favorable, we actually didn't have to worry about it at all, for the past days. If it is not favorable, we didn't still have to worry for the past couple of days, as now we have more time to worry about it. :D My suggestion is, do not worry about the future events unnecessarily. It gives nothing. Each day throws more physical and mental challenges on us. We survive and thrive. We naturally do not worry whether the tomorrow be the last day of the planet, or at least for the individual, where the possibilities are pretty high.

In a parallel world

If we really think about the life events, we can notice one pattern. We can't actually pictorize our life in a chronological order. We remember the events in chunks, instead. For example, I can think about the university life of 2006 - 2010 the lectures, the time we wasted together with friends, and the Google Summer of Code developments (2009 - 2010). But I can hardly multiplex them. I remember how the coding with GSoC was interesting, and also remember the nice times we had at the university, mostly in an independent manner. Because, the life is parallel.

Memories

No matter how hard a situation feels at the moment, the memory it leaves is always a positive one for me. The first half of 2012 was not so easy, and it was full of challenges. However, when reviewing them after a few months, I don't have anything strong to regret. I just have the good memories of the array of events. Minor things we do often make a good memory after a year or two, if not by the end of the year. I am pretty sure the shuttle travel to Taguspark, highly interactive lecture sessions, living alone for the first time, having mixed feelings intermittently, stepping back and thinking positively, these weekly blog posts, and exploring Lisbon - everything will be very interesting memories!

Lisbon - Week10

2012-11-02T04:59:00.004+05:30

Halloween - Balloon to the sky from Bairro Alto

[01/11/2012] Amidst a busy schedule of lectures and projects, we got a long weekend of four days with the All Saints Day today. We decided to join the Halloween at Bairro Alto, Wednesday, the 31st night. It was interesting.

Is Freelancer.com a complete scam, or a partial scam?

2012-11-02T04:24:00.000+05:30

Reviewing a website or service is mostly not the target of Llovizna. However, due to the increased population of Freelancer.com, I wanted to provide some feedback and cautions on using this site.

Freelancer.com, as its name suggests, a web site that lets the freelancers meet the employers, or task/job/project providers. It is based on Australia, and has grown to a very high level that no other freelance company or organization can even reach. The strength of such web sites is its users. Freelancer has plenty of it. You can compare this with Facebook. While everyone complains about the Facebook's policies, no one bothers to switch. Why? Other websites do not have the users!

If you search the Internet as a user who got annoyed by Freelancer, you may find multiple complains. I hope a few of the suggestions I give here will be of use to you.

1) Chances are high that you will just lose money, instead of earning

After a several bids, you are awarded a project from an employer. Now you gladly accept the project. Freelancer will charge 10% or 5% of the full amount immediately, based on your subscription. Only the Enterprise accounts are not charged for the awarded projects. But the monthly subscription is extremely high for that. So as a starter, you will not consider that anyway, and all the beginners start with a free account, where they are charged 10% of the full amount from Freelancer.com, immediately they are awarded a project.

As a newbie, chances are high that the experienced employers will not hire you. That means, you are getting your project from a newbie employer. In other words, an employer without any reviews. He may be a fraud. He may just try to get the job done, and leave without paying a cent. Freelancer suggest requesting a mile stone payment model for this, where you request at least 20% (suggested is 50%) of the complete amount. You start work only after getting the mile stone created. Once the mile stone created, the money will transfer from the employer's account to the Freelancer.com's bank account. So the chance of the employer cheating will be minimal. Once you have completed the job, the employer will inform Freelancer.com that the project is completed and hence the payment can be released.

However, say, the employer decides to stop communicating with you, as soon as you accept the project. As Freelancer.com suggests, you will not start working till he creates the milestone. You may avoid working without getting paid, in this manner. However, even if you decide to abort the project, Freelancer will not refund its charges, in ANY case. This is clearly mentioned in its FAQ. That means, if you accept a project worth 500 USD, your credit card will be immediately charged 50 USD. Whether the employer is genuine or not is not the question. Some Freelancers have even questioned that Freelancer.com may create fake employers who allure the freelancers to accept high budget projects, so that the Freelancer.com earns a huge fees from the clueless freelancer, where the freelancer will not earn a single penny from the employer, probably even after completing the entire task, as the employer is a fake!

2 Possibilities:

Worst Case: You will not be completely paid the 500 USD, as you are new, and hence met with an evil employer. You will end up with a loss of 50 USD, and with an incomplete project which will ruin your freelancer.com profile for eternity.

Best Case: You got an awesome project and an awesome employer, who promptly pays 500 USD. Note that your card was charged 50 USD in day-0, and say you complete the task in day-2. You will have to wait for a month or even two, to get the first payment from Freelancer.com. Check the next point (Point-2) given below to see why!

2) Getting your first payment out of Freelancer is a nightmare.

Let's say, you have successfully completed your first project and want to get paid. Now comes the troubles. For some unknown security reasons, they have included a 3 week period of verification, before the first payment. That means, employer pays the complete amount, fully satisfied with your job. This broker (i.e. Freelancer.com), decides to keep your amount in 3 weeks, in their bank accounts.

Let's think of a few cases.

Case 1:

You get paid for a project - 200 USD. You request withdrawal via paypal for 200 USD. Reducing 1 USD, they schedule 199 USD, to pay in 3 weeks. Now, within that three weeks period, you are awarded another project worth 100 USD, from the same or another employer. As you accept the project, Freelancer will immediately charge you 10 USD (or according to your subscription). Where will they charge from? Not from your credit card this time. They will charge from your Freelacer.com balance instead. Now the balance will be 200 USD - 10 USD = 190 USD in your account, where your previous request for the transaction was 200 USD. With the below message, Freelancer.com will cancel your payment request! "Not enough funds to complete your withdrawal request!"

You may request for 190 USD again now. They will schedule your payment now. But it will be scheduled again for a day after 3 weeks, again! Wait for 3 more weeks!

Case 2:

You have a basic subscription. You, as in case 1, have asked a transfer. Since you know that accepting a project at this moment will cancel your payment request, now you are cautious. You will try not to withdraw the complete amount. Say, you request just 100 USD, to avoid facing the above mentioned issue repeatedly, or you decide not to work with Freelancer.com till you receive your first 200 USD withdrawal request. Now, assuming that you have a subscription with a monthly fees (not a free account). Within 3 weeks, the next month will come and Freelancer.com will charge the monthly fees from your balance, and cancel the transaction request as in Case-1. Freelancer.com will give an evil smile to you, as a big troll!

How to avoid these?

1) Once you have received your first payment from Freelancer.com, the consequent payments are done twice a week, and hence will not take much time. Freelancer.com feeds on the blood of the newbies. Hence be cautious. Once you received the payment for the first job, do not try to withdraw the entire amount. Chances are pretty high that the balance will go negative, and your payment request will be canceled, as we saw in previous cases. Request withdrawal for just a part of it. Say, 150 USD (75%), instead of the entire 200 USD. Avoid accepting any big scale project, till you receive your first payment. Once you have received your first payment, you will become a master, and will not require to read this blog post at all.

2) Avoid having multiple currencies in your account, and try to keep USD as your default. Say you keep Euro as your primary currency. When you are awarded 200 USD, you decide to change half of it (100 USD) to Euro. You will have to face additional hurdles by this.

* Freelancer.com money conversion facility is not free. It will charge you.

* Say you have 100 USD and 60 Euro in your Freelancer.com, as you have transferred a 100 USD to Euro, as above. Now you have requested the withdrawal of 60 USD, and your primary currency is Euro. At this moment, if a project is awarded, or if Freelancer.com decides to charge you the monthly subscription fee, they will surely charge from the 70 Euro, as it is your primary currency, and they will not touch the 100 USD. That means, though you felt that you have balance in your account, so that your transaction is safe, it is not safe, in real. Freelancer.com will get an additional chance to delay your payment by further 3 weeks. It is better to keep the balance in a single currency, which is also your primary currency, to avoid this. In other words, better to stick to USD.

3) Avoid accepting suspicious projects.

A few cheats opens jobs with very high amounts, targeting the newbies to cheat. In these cases, the employers themselves too will be new, or at least will have negative ratings. It is always better to avoid the first project with a higher value to reduce the risk of immediate money loss to Freelancer.com in the name of bidding charges. Within a few days of testing, I just lost 50 USD to Freelance.com, just because I accepted a project from a suspicious employer, who didn't bother to respond further, after I accepted the project. Probably, he must have thought that I am clueless, and would work without getting the milestone payment requests accepted (without getting paid).

By being extra careful, you will be able to receive your first payment within a month, escaping the dirty tricks of freelancer.com, and once you have received your first payment, you will be fine with the game! Hope this long blog post was useful for you. Wish you all the best, and hope to see you soon with the critical analysis of yet another service.