Aspects of Energy Consumption and Saving in Computer

We are living in the era of computers. We are using computers in every field and we always measure the performance of computers in terms of speed and portability. But do we ever have spoken in terms of energy? Do we know how much electric energy it consumes?


Today we see power cuts in our cities and energy sources like petrol and diesel’s prices are moving out of normal man’s reach. Seeing all these things do we ever think about saving energy while using computers? In this article I have put some information which can help you in saving energy.


Our Desktop computer uses about 60 – 250 watts of power where as some other computers use more. With most devices we can look at the label to see how much energy it can consume. Each part in computer accounts for different level of energy consumption. So architecture of computer will determine the power consumed by that system.

How much power computer used to consume in earlier days?
The first electronic computer was invented in 1946. Since then lot of changes have occurred in the architecture and organization (material which they are made of) of computers and hence the power consumption by the computers. Earlier computers were using vacuum tubes and it consumed power of the order of several kilowatts ie thousands of watts. The ENIAC computer could perform 5000 arithmetic calculations per second, weighing 30 tons, containing 18000 vacuum tubes, consuming 150 kilowatts of power. EDVAC consumed 50kwatts. ORDVAC consumed 35 kwatts and UNIVAC-I consumed 124.5 kwatts on an average (these are all earlier computers). The power is dissipated both by the action of the switching devices contained in the CPU (such as transistors or vacuum tubes) as well as energy lost in the form of heat due to the resistivity of the electrical circuits.


Computer organisation and architecture - a major factor in power consumption
Do you know microcontrollers? These microcontrollers are used in embeded technology like robotics etc. Once I asked one of my friends working in the field of embeded systems: “can we replace microprocessors with the micro controller in PC’s?”. He told many reasons and one of them was if we use microcontroller of microprocessor capacity, it will burst whole PC(personnal computer). Because power consumed by it and hence the heat produced by it will be more. So architecture and organisation of computers and its implementation has a major role in saving energy.

In earlier days the CPU component was accounted for most of the power consumed. Now a day, majority of the computer’s energy is consumed by monitors.


CPU
But today we have CPUs like Intel XScale that can consume only 0.5 watts of power. We are able to find CPUs consuming power in the range 9-125 watts of power. If we are using a mobile (Motorola) it uses only 3 watts when we are on call and 2 watts when idle. AMD 64 FX a multicore processor uses about 125 watts.






Monitor
If some one wants to buy a computer he will first see speed of processor, then memory requirements (both primary and secondary) and then he goes for the monitor. Different varieties of monitors are coming in the market. Conventional computer systems have used cathode ray tube (CRT) technology for the computer display. However, in the past decade technological advances in Thin Film Transistor (TFT) Liquid Crystal Displays (LCD) have made this increasingly popular. Do you know why? There are many reasons and one of them is power saving.


DO LCDs save energy?
Yes. LCDs use considerably less energy than CRTs, both when running and also when in standby mode. Overall, LCDs can reduce display energy use by some 60%. For
example, a 15” LCD uses around 25 watts when operational and around 3 watts when in
standby mode, compared with an equivalent viewing area 17” CRT that uses 80 watts when operational and 5 watts in standby mode. LCD screens recover from standby faster
than CRTs and consume less power when they do this. LCDs do not emit the same
heat load as does a CRT , and this saves energy on air conditioning in a building. The uniform brightness of an LCD screen means that the screen can better tolerate variations in light levels, and reductions in lighting also saves energy.


A Japanese study in the beginning of 2003 estimates that if Japan continues on its path towards replacing old CRTs with new LCDs so that some 76% of displays will be LCDs by the end of 2003, this will save 3 billion KWh of power consumption (the equivalent of the total power consumption of 1,000,000 households or the power production of about 3 nuclear power plants).


The Laptops and TFT monitors use this LCD technology. Our laptop uses about 15-45 watts only, that is very small compared to what CRTs consume.




What is LCD ?
I think people have heard about LCD. Now a days, TV with LCD screen is very popular. LCD -- the name itself is little confusing. Liquid is completely different from crystal, then what is this Liquid Crystal!! They are neither liquid nor solid. Liquid crystals are closer to liquid state than solid. It takes fair amount of heat to change a suitable substance from solid into liquid crystal. It takes little more heat to convert into real liquid. They are very sensitive to temperature. It works on the principle of polarization. It is placed in between two polarized glasses.


Now a days TFT technology is used in LCD which will save more energy than earlier passive matrix LCD displays. The benefit of a TFT monitor is a separate, tiny transistor for each pixel on the display. Because each transistor is so small, the amount of charge needed to control it is also small. This allows for very fast re-drawing of the display, as the image is re-painted or refreshed several times per second. Since amount of charge needed to work is small, the power consumption is also less.


Here is some information about power consumption by some monitors.







Are we switching off monitor while not using it?
Some people are used to sleep, listening to songs in computer. In such a situation they always forget to switch off the monitor. If we are copying something, suppose it takes lot of time and we are not doing anything else in computer, so better we switch off our monitor. It will save lot of energy. If we turn off monitor it will use only 0-10 watts of power.


Adjusting power settings on our computer to automatically go to standby/sleep mode after few minutes also saves energy. In sleep or standby mode it will use 1-6 watts of power. Here is some information about the power consumption by a monitor in different mode.



Apple iMac G5 w/built in 20" LCD screen





This is all about how much the main components of computer consume power. Whether the power consumption depends on the tasks we do on computer? Processor intensive tasks and I/O intensive tasks consume more energy. Email and word processors consume less energy where as the computation done by ALU (Arithmetic Logic Unit) uses more. Copying of files from CDs and other I/O devices use more energy since it is related to memory.


Some people think that putting screen saver saves energy. But it is not true. It is recommended because it keeps CRT safe from damage. If you click refresh it will also consume energy.


This is all about importance of energy in computers. But computers account for only a fraction of worldwide electrical use, even with the burgeoning Internet usage. Air conditioning, lighting, refrigeration, etc. account for a lot more. In fact, as inefficient CRT monitors are being phased out in favor of newer LCD screens, energy consumption by computer is likely to remain flat or even go down over the next several years.




This article is published in our college magazene.

As I move towards you

As I move towards you,
I fear of my moving legs.
As I hear the voice of you,
I fear of my hearing ears.
As I feel the presence of you,
I fear of my feeling sense.
As I saw the beautiful eyes of you,
I fear of my beautiful eyes.
I don’t know why I fear of you?
But I fear of my own existence.

When I first saw you,
I start looking at you.
Your smile made me mad for sometime.
But I wanted to be mad at that time.
Your eyes made me to drive in dream.
But I wanted to be driven in dream.

As if the honeybee attracted towards flower.
I was attracted towards your likings.
As If the wind blowing towards sea,
I was moving towards sea of beauty.

I don’t know why I am in love with you.
But its love of great height and dream of several miles
You like me or not.
It’s the fate of my life and destiny of my love.

I don’t know why I fear of you?
I fear of my own existence.







My first and worst poem. I want you people's suggestion so that I can preserve this poem for my future also.

ತೇಜಸ್ವಿ

Ujire : Not just memories

She was dressed in white, curly hairs with bob cut. Her smile added to her beauty. For a second, I thought I was in some other world. She looked descent and I wanted to talk to her. But I did’nt have that much courage to go ahead and talk to a girl freely. As I was thinking about all these things she has already left. I just thought she is too much high level girl and I wanted to leave that matter there only. But it was not easy for me. I saw her singing on the stage and her melodious voice touched my heart. I thought it was just a infatuation and wanted to leave it.

I was in hurry to the college as I was late already. While I was on the way to college, I saw a little girl fall while running. She was profusely bleeding. I just took her to a near by shop and bought a band-aid and pasted on her wound. She was cute and told me thank you uncle. I said you could call me Brother or friend instead of Uncle. As I was in a hurry,I forgot to ask her name. After few days I met her again. I heard the sounds of somebody calling Uncle. I turned back, it was the same little girl. As she addressed me Uncle I replied “Hello aunty how are you”?.She smiled at me and gave me a chocolate. For my question she smiled and she gave me one small chocolate. I do not know if I have ever got such a happiness from anybody. It was a joy what my Dad used to get seeing me happy, it was a joy my sister used to get whenever I used to do some mischievous thing. I asked her name and she told me T______. After hearing that name I was in the fourth world. I just took her to the shop and bought her a dairy milk chocolate. She smiled and went to her school. After that I met her many times and whenever I met her, if I was alone, I used to give her dairy milk. She is a sweet sister. She is the sweetest part of my life in the two-years journey in Ujire.

I was attacked by Anemia at the end of my 1st PUC. I took my Dad to Kumar Hegde Sir. In lab how he used to scold me for poor drawing. But now he was calm and told me you will be given entry to next year without exam if Principal gives permission. He took us to Principal chamber. I always respected my principal and also I feared him the most. He asked me are you in a position to take the examination ? I don’t know what answer I wanted to tell but I said I would write my exams. It was a miracle I passed my exams with 1st class.

I was very happy that day. I saw her so close. Some of the biology students were put into E section which is meant for computer science.” Now she is my class mate”, that feeling only made me very happy. Her innocent smile, her entry into class, more than anything her melodious voice put a fire in my heart. This fire just kept me cool in summer and warm in winter. I never wanted to fall in love once again but I was out of control.

One day Mayya Sir stopped me while I was going with my friends and asked me why are you so dull these days. You were very active in my mathematics class. Now a days the smile is missing on your face. Any problem? Defending me my friends told now a day he is concentrating in language classes. That was not true but when I have no answer for his question I shook my head. I just never saw this change in me. I thought too much into what he said. Why I have come here? My dad has never forced me on anything. He has supported during my failures too. I thought I have to study well and started studying seriously. But it was too late. Once again I was attacked by anemia. I consulted doctor and he told its dehydration nothing else. I had no choice but to face exam. Otherwise I would have missed one year.

Dad came to Ujire during my exams. Parents did not have the previllege to stay at gurukula. Dad stayed in Dharmastala and morning he came to take me to the exam hall. My eyes were totally blocked. I sat in a wrong seat, as I was not in position to see my number correctly. Later the lecturer took me to my seat. In same tiredness I faced 5 exams. During my Sanskrit exam, I recovered bit and faced my exams with some preparation. Except that exam the other exams totally went bad including my favorite physics and mathematics. When I reached home I got to know I was suffering from anemia. For 30 days I took complete bed rest and some how managed to write CET exam.

After my last exam, I took a glimpse of the entire college for a moment. I thought my life is incomplete without all these experiences. I will miss my friends, I will miss the unity of E section, I will miss Siddavana’s electrifying atmosphere, T______, I will miss T.N. Keshav, Mayya Sir, Kumar Hegde, Naveen Sir , Ganesh Hegde , each and every staff. I will not get a beautiful teachers like this. I will not get an entertainment class like Purohit Sir’s Sanskrit(some time very boring). For the last time I wanted to say sorry to Ramya madam for the stupid discussion in English class. Finally I didn’t talk to T______. More than anything I missed the small kid T______. I don’t know I loved the small kid too much or my love. But I changed my dairy name to the small kid’s name. She used to say, “ Uncle sorry bro, if smile is not there in your face you doesn’t look good”. She became an inspiration for my smile and my love became an inspiration for my poetry.

Janata : Haunting memories

I just don’t know what is going on in my mind. I will not be here where I spent my most memorable days. I just miss all my best friends, Sumukh,Shivappa(Shiv Prasad),Shreyank,Sharma,Yogi,Sumant, Hari ,Madhu,Nischu,Prasanna,Gonza and ofcourse Sanskrit class. I will miss the days where I used to sit in the back seat of Sumukh’s bicycle. I will miss the days where Shivappa and me sitting together in the class and commenting on all. I will miss having fun in Nischal’s home. I just miss Hari’s mimicry, Sharma's cool nature, Yogi’s scolding, Shreyank’s smile . How he was making fun of my innoscence. I will not get a good person like Sumant in my life. I will no longer be having company of Madhav. Combined class especially the SNB class is most enjoyed class till date. A journey of last bench in Sanskrit class, KCA questions, HS jokes, GGK (kara kara madtare) dialogues, SG’s quiz competition, comedian RJK, 2 row beautiful girls, Prasanna’s PJ ,Shruti - Madhuri Dixit of our class , Stephu, St Joseph group and all who were with me and unforgettable BRV all have added to this spicy journey. Not to forget BJK. He used to comment on my inability to ride bicycle. One day I will show him for flying planes bicycle is not needed. Whenever I will see students standing for prayer I will remember we were standing in the class till Hemamalini BRV madam comes into class. Oh! God I can’t forget pin drop silence in her class and she looked like a beautiful devil to me.

In spite of all these I don’t want to return to Sagar. I can’t forget what happened to me here. I just want to forget R____. Except her episode everything has been tremendous joyful. . I wanted to say Sorry to her, but I don’t have that much guts to do so. I know my mistake and I will try not to repeat it. My best friends may have not come in difficult time including Abhilash, but I will take only positive memories to Ujire. May her memories won’t haunt me in near future.





This part I have written when I have been to Sagar to get my TC. It was one of the joyful innings of my life. And also I learnt how to move away with life if any thing comes in the middle. This part is one of the finest lines in my dairy. This was in very crude English and I have only changed to fit into the context.

Fear of loosing the Dearest one

When life entered the crucial phase,
The mother of all the phase,
As if I was thinking to quit
You made me very easy to think,
Whether to concentrate on my career
Or to move with my friendship.

When I moved with my life
The life of uphill task
As If I was tired of trying
Your smile made me to go ahead
With my tough endeavors
To catch my goals and aim.

When I was on the first step
The step of series of failures
As If I was moving away from success
Your life inspired me to get up
With my weapon of imagination
To fight the spines and obstacles.

But now when I get the one chance
A chance of showing my desires,
As If I was clearing all my negatives back
Your death made me a helpless friend,
With all the love you have given to me
I failed to give it back at the end.

When I saw the Terror of Taj
The cruelest scene I have ever seen,
As if I was trying to forget you,
The faces of them made me to cry.
The innocent lives gone,
But we couldn’t do anything.

When the entire nation dipped in sorrow,
The faces were clearly saying.
As I can't control my emotions
Memories came breaking my tears.
I pray Fear of losing the dearest one
May not come to anyone.

This poem is dedicated to the victims of Taj attack by Terrorists and my dearest friend Akshata who died last year.

A innoscence I missed everytime

I was on the non striker's end. Sachin Tendulkar was on striker's end. It is always pleasing to see Sachin bat. I was witnessing the 8th wonder of the world so near by. He was on 50 and I was still to open my account. I have already wasted 10 balls. He came close to me and told me nothing to worry. Play your natural game. It was Wasim Akram from the other end. I was sweating to see him at the other end. This time a bouncer from him, I hit it for six. Oh God I can’t believe it. It gave me full of confidence on my abilities. In next 30 balls I reached 98. What a wonder! So It was so close to my debut hundred. Who doesn’t want to achieve this feat alongside God of cricket? But my faith was totally different. She was moving near side screen. Oh! God what she is doing here? I couldn't concentrate and was clean bowled by Waqar yorker. "putta get up ", My sister voice hit my ears. Oh! God why didi also came to see my nervous ninety? As I was thinking about this, some one poured water on my face. As I got up I came to know that it was just a dream. Finally my nervous ninety dreams ended with my sister pouring water on my face. Even in my dreams P_____ coming.


Yesterday was Rakhi day. Whole school tied me rakhi. My right hand was full of rakhies. I was deliberately hiding from the scene. I didn’t want her to tie me rakhi. As I just passed the school gate, all my little sisters were holding rakhi. I was searching for her to see whether she will also tie me rakhi. She was not there. I just went to classroom. All my sisters including two little Ramya tied me rakhi. Suguna and all my classmates tied me. Thanks God she came and talked with me and disappeared with C______. I don’t know why I am thinking all these nonsense. But now a days in my dreams not only cricket and space comes but she is also coming. God please help me to overcome this. People have lot of expectation from me. Didi, Dad,. Mom everyone has lot of expectation. You just save me from this stupid nonsense thinking.

This was when I started writing dairy. In 7th standard I was writing diary in a raw manner. That was in Kannada and I have translated this into English and some words I have changed to beautify. Wonderful memories of my life. Today I laugh while reading these stuffs. In 7th standard only ............. . I never blocked my emotions. I thought let it flow like river of water so that my mind can peacefully enjoy the beauty of life. I named my Diary Honey and later it is changed to some persons name whom I became a big fan.