RT Linux, Sreejith and ‘Why ? Why ? Why’

Posted in Free Software, Home at 5:55 pm by Pirate Praveen

Noted on 19 May 2005

On this Thursday (19 May), I decided to visit my friend. But when the phone didn’t give any reply I tried calling Sreejith. He was in Chennai for his final year project at AltoSys on RT Linux ie, Real Time Linux, when I called him last week. Here the result was an engaged tone. I was really confused as I told my grand mom and aunt (Valliammayi) that I will be going to Mannarmala (which I planned after this) and I won’t be coming back today. I’ll have to go to Mannarmala in the morning itself. I tried to call my aunt at Manjeri to see whether Sheenechi has come back from Bangalore. I was told that she will be back only on 30th which I confused to be on this week. [This was the second or thord time in the 3 weeks, I went wrong with a ‘date’ !! I missed Changathikkoottam before, I thought it was on 8,9 and confused it with 7,8 and I was sure of 8 and when I went there I came to know that it was really on 9,10 !!!]

So next I dialled KD [ not a ‘known defaulter’ but my friend Kiran Das, we used to call him KD or K’, read K-dash] and this time I was lucky to get him on mobile [I have been trying to call him all these days but couldn’t get as he didn’t have range at home]. I told him I’m coming straight there. But he had to go to Ashram to meet his uncle and he may have to move to Mookambika.

Again confused as where to go. I thought that I’ll go to Mannarmal and try calling Sreejith and if I get him, I’ll go there. I tried for the last time (about 10th time) if I can get to Sreejith.

Oh! This time when I dialled Sreejith was on the other side. He told me that a small kid (his sister’s daughter) might have mis placed the receiver !! I told him that I’m coming and at first he told he is busy as his mother, sister and others are going to Chennai to meet his mother’s sister. Then he told me to Ok and I went there.

After the initial chitchat we had lunch [I reached there by noon]. Then we sat and discussed a variety of issues and shared new ideas and applied some old concepts to new areas. He described about his experience in Chennai with AltoSys project on RTLInuxPro (which costs 2 lakh INR and 7 lakh INR with the source code). From AltoSys site :

We have partnered with FSMLabs to support and distribute their world renowned flagship product RTLinuxPro in India. RTLinuxPro is the most comprehensive Real Time Operating System (RTOS) that offers a complete development environment to develop mission critical real time applications which cannot offer to miss deadlines and deeply embedded applications which have started to find inroads in to every electronic gadget that we think off.

RTLinux can be installed to linux kernel and which can be used for hard real time systems [VxWorks, which is based on BSD and QNX are other platforms used for Realtime applications development]. The system which we use for our everyday purpose [say GNU/Linux or Ms. Windows] are soft real time systems, which can tolerate some lag in response [Ms. Windows users might remember how ‘fast’ sometimes the system responds!]. Once this module is inserted, it stops all interrupts to the linux kernel. It considers the entire process tree under linux kernel as a single process with the lowest priority assigned to it. The difference in RT application from the normal ones is the very fast response [very small response time]. If we schedule a task to start after 10ms it will start after 10ms what may happen. Their project was speed control of a motor with RTLinux [using the freely available RTAI toolkit]. He told me about their project presentation [He is great at explaining things . He explained to me all fandas of the Matrix movie when we met last time and I became a fan of the movie after that and watched it when I was back in college]

We can visibly differentiate the sequence of an LED blinking which is controlled by RTOS and non-real time OS [He has developed install scripts for installation of real time linux . It is a 40 MB bundle with entire toolkit with network support and he plans to improve it with Makefies, which he learned at Altosys]. The recognisable pattern changes if we load the system by launching some applications. The same thing when repeated eith RTLinux preserved the same sequence of LED blinkings. The pattern was intact whatever be the system load. Their project was to regulate the speed of an electric motor. Suppose we set a target speed of 3000rpm, then the first priority of the system is to achieve this speed when it is started. Suppose if we load the motor or apply brakes and when the speed fall below a set value, the supply is increased so as to reach 3000rpm.

Altosys has collaborated with FSMlabs USA and their projects are mainly for DRDO. He said that during training the examples used were Agni, Brahmos etc. For these computer controlled trajectories response time is critical, if there is a small error ie, there is delay in starting a process and exceeds the limit allowed, can in turn create very large errors.

He raised concern that if every software is open sourced, the section that cracks the software and is not in the main stream comes out to service sector causing job loss to the main stream and destruction of IT industry as a result!! This is a baseless argument and based on a common mistake that most perceive. They tend to believe that a FOSS product is one which is developed by a company and distributed free of cost with source code for everyone !! They don’t understant it is the process that help evolving such great softwares like Firefox and Samba which has got hackers around the globe working on it and improving it. [The developemnt in FOSS is not done by a single company but a large number of individuals around the world. The number may differ depending on the scope and size of the project]. It gets feedback from users in the early stage and everyuser will have what they will need from the software when it is evolved and it uses a lot of already available resources rather than starting from scratch [code reuse]. The classic example is the K3b CD burner which comes with KDE which uses a lot of command line tools to bring out an easy gui to these tools. It looks and works great. [NITC main CC gives users Suse GNU/Linux with k3b for CD burning and I burned all my CDs with that only]. Similarly Mplayer uses FFMPEG codecs for playing multimedia content.

He also says if all the software becomes FOSS, the system becomes symmetic and the world does not exist in such an ideal condition [of everything the same] and he says the world is asymmetric. If we look at each case individually things may seem different but there is an underlying symmetry in everything. I told him about De Broglie’s priciple of matter waves. He says nature loves symmetry and so if waves has properties of matter then the matter also has got properties of waves [eg. wavelength] and this is the basis for the so called matter waves. Can you think of the wavelegth of a Cricket ball’s associated wave ? [well we study how to calculate these in Plus Two Physics]. He also agreed upon the symmetry when we look things as a whole from a wider perspective. The best example is the golden ratio, the number psi which I read about in Dan Brown’s Da Vinci Code. Nature loves symmetry and tries to achieve it. We all can look and live for a better world with every human being gets equal due.

‘Why ? Why? Why?’ is a book by KSSP in malayam that gives scientific answers to many common Whys. I have been reading it in the free time in Mannarmala.

[Comments and discussions on these thoughts are welcome. I may get another perspective of the things and I can learn it too.]

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