Title.
The Greatest Blessing
Gautam Mehrotra was sitting in the living room and reading the newspaper. It was a Sunday. He had just finished his breakfast and was trying to catch up with the rest of the world. Gautam had retired as a senior executive assistant in the Collector's office, after thirty one year's of service, ten month ago. Soon after retirement he had shifted bag and baggage from the district to his son Swaroop's house in the city. Swaroop was a cashier in the State Bank of India and lived in a tiny apartment with his wife Rina and son Nikhil. The flat had a living room, a bedroom, a kitchen and a small dining space. The cramped set up was on the third floor of a ten storied building.
Six year old Nikhil was very fond of his Baba and would sleep with him in the living room which was converted to a makeshift bedroom at night. Gautam too was enjoying his retirement life. He would play with Nikhil, tell him stories, take him to the park or the nearby markets and sometimes read a bit. In the District, all alone, after the death of his wife three years back, he had felt suffocated. But here with Nikhil for company he felt comfortable and relaxed.
"Babuji, I want to discuss something with you," Gautam looked up. Swaroop was standing with a worried expression on his face."
"Sure Roop come and sit." Swaroop sat down and kept looking at the ground. It was clear that he was feeling uneasy. Gautam looked at his tense face and asked him gently.
"What happened Roop? You look very serious. Is anything the matter?"
"Babuji, actually there is a problem. Rina has got a job as a saleswoman in a boutique."
"A saleswoman? But why?
"We need the money. The way the cost of living is shooting up we will not be able to manage only on one income. Nikhil is growing up. I want to give him the best education. Where am I going to get the money from? The three hundred rupees which you give every month too just disappears. I am hardly able to save anything."
"But surely you could have thought of a better job, a job which is less taxing."
"Babuji, you know jobs don't grow on trees. Rina is not even a graduate. Where is she going to get a job of her choice. We have to grab whatever is available."
"But Roop how will the poor girl manage her job and her housework?"
"That is where we need your help."
"Sure. I'll do whatever I can."
"Babuji, Rina will have to leave at nine thirty and will reach home only by around seven thirty. She will not be able to cook lunch or serve you the evening tiffin."
"No problem, Roop. She can make some extra rotis and sabzi. I'll have the same things for breakfast as well as lunch. As far as the evening tiffin is concerned, I'll make a light snack for myself. You don't bother about me. I can take care of myself. What I am worried about is Nikhil. You know how fussy he is about food."
"I have thought about that Babuji. Rina has talked to Mrs. Desai who runs a crèche in the opposite building on the second floor. She has agreed to admit Nikhil. In the morning, as usual, I will drop Nikhil in his school. At 2 p.m. when the school closes Nikhil will go in the same rickshaw, which he uses now, to go to the crèche. In the evening, by around six thirty I will pick him up. Nikhil will have his breakfast at home and lunch and evening tiffin in the crèche."
"But Roop, if Nikhil spends the whole day in the school and crèche , what will I do? I'll go mad just sitting at home all alone."
"I was thinking.....I... feel....," Swaroop hesitated and then said in a rush, "Babuji, there is a very good institution in our city. It is called 'Home and Hope'. It is run by an elderly Parsi couple - Mr. and Mrs. Wadia. I feel that you will be far more comfortable there. You will have good company - people of your age. I have been there. It is very nice place - neat, clean and well maintained. Its not very expensive. The three hundred rupees which you give me every month will be sufficient. And in case you need anything I am always there. And one more advantage is that there are quite a few diabetics there. The people who manage are used to preparing a diabetic's diet. So you shouldn't be having any problem. And Babuji, with Nikhil in the crèche and you in 'Home and Hope' Rina and I will be assured that the two of you are being taken care of and will be able to concentrate on our careers."
Swaroop stopped and looked at his father. Gautam was too shocked to say anything. He just sat in stunned silence: 'His only son wanted to dump him in an old age home'.
"When do you want me to leave," asked Gautam, his voice, his face giving no indication of his feelings.
"Rina has to report for duty next Monday, so I'll shift you the coming Sunday. And Babuji you need not worry about anything. Both Rina and I will be coming regularly to see you, along with Nikhil. I'll also be in touch with you over phone. I am sure you will like the place."
• • • • •
Nikhil was feeling miserable. He was sitting in the crèche staring blankly into space. Desai Aunty and her maidservant Tulasi were busy watching a serial on Zee TV. Debu, Rosy and Jay were playing cricket on the terrace while Munni and Vinil, the younger ones, were sleeping in the bedroom. Debu was older to Nikhil while Rosy and Jay were the same age. Debu was a bully and would keep pulling Nikhil's ears and calling him silly names. The other two would join him in making fun of Nikhil.
Nikhil hated going to the crèche. Desai Aunty was rude and Tulasi very nasty. The food Desai aunty cooked also tasted horrible. He had complained to mummy but she only scolded him. "Nikhil, you have to learn to adjust. You can not always get everything you want. And anyway you are having only lunch and a little bit of tiffin there. For breakfast and dinner I'll make things of your choice, okay?"
He had nodded his head.
One day mummy had given him two boondi laddus and an apple. Tulasi had given the apple to him and hogged the laddus herself. Nikhil had told mummy and she had spoken to Desai aunty. A few days, in the afternoon, when Desai aunty was sleeping Tulasi had confronted Nikhil. "You little runt. How dare you complain about me. Next time you squeal I'll tell my brother Rana who is a dada. He'll give you such a thrashing you will forget about Daddy, Mummy and everyone else.
Nikhil was terrified. After that whenever his parents asked him whether he had any problems in the crèche he said no.
At home too he felt very lonely. He missed his Baba very much. He had suddenly left him and gone somewhere. He still remembered that day very clearly. It was a Sunday and he had found Baba packing his bags.
"Baba are we going somewhere? Are we going to Bua Dadi's house?"
Baba's sister lived in a village on the outskirts of the city. Baba had taken him once there. They had spent three days and Nikhil had really enjoyed himself. Bua Dadi had made lovely things for him to eat - kheer, gajar halwa, hot samosas.....
"No, Nikhil, we are not going, I am going."
"Where Baba? Take me with you, please ."
His father had entered the room just then. "You can't go with him, Nikhil."
"Why?"
"Like you go to school Baba is going to his school."
"You are lying Daddy. How can Baba go to school. He is not a small boy."
"Yes, son, I know he is not a small boy. That is why he is going to a school which is meant for old people."
Confused Nikhil looked at Baba. But Baba continued his packing without looking at him. Nikhil knew something was wrong. He went into the kitchen and asked his mummy, but she too was evasive.
He went back and asked Baba. "When will you come back?"
"I...I can't say son," Baba replied, not meeting his eyes.
"We'll go and visit him every week," Daddy told Nikhil.
Just before Baba sat in the auto, he picked up Nikhil and hugged him. Nikhil clung to him and started sobbing. Very reluctantly Baba handed Nikhil to his mother and wiping his eyes got into the auto.
That night Nikhil refused to sleep alone in the living room. Finally after a lot of shouting and screaming he was allowed to sleep with his parents in the bedroom. However, in the middle of the night when he woke up he found himself all alone in the living room. He looked around for Baba, but he was not there. Then he remembered, his Baba had left him and gone away to his school. He started sobbing loudly. A few minutes later his mother came and took him inside. He still couldn't sleep for hours. He just clung to his mother and cried his heart out.
The next few days Nikhil insisted he would sleep with his parents. One evening his father told him, "Son you are now a young man. You have to learn to be brave. If you get scared like this everyone will call you a sissy."
"But Daddy without Baba I feel very lonely. I keep thinking about him and start crying..... and..... and Daddy when the lights are switched off I also get scared."
"Nikhil you should not behave like a cry baby. You want to meet Baba, don't you?"
"Yes," Nikhil said his face lighting up.
"Well then if you agree to sleep alone I will take you to meet your Baba this Sunday."
Nikhil quietly got up, picked up his pillow and went to the living room. There he planked himself on the sofa and tried to sleep....
• • • • •
Sunday morning Nikhil got up feeling very excited. Today he would be meeting Baba. He quickly brushed his teeth, took a bath, ate breakfast and drank his milk without any fuss. By nine he was ready.
"Daddy, I am ready. Let us go."
Swaroop was watching the serial Chandrakanta on TV. "Go where?"
"To see Baba. Have you forgotten? You promised to take me to meet Baba. I am ready. Let's go."
"This early? Don't be silly Nikhil. Can't you see I am busy now? Moreover after watching this serial I have to go to Mirza Uncle's house. I'll take you in the evening."
Nikhil's face fell. He was really disappointed. He wanted to protest, but he was scared. Daddy might get angry and not take him at all.
At five in the evening Swaroop took Nikhil on his scooter. After travelling for almost an hour they reached a building at the end of a lonely road. It had a compound wall with an iron gate. They went in. The building was quite badly maintained with cracks in the walls and the paint peeling off. The pathway to the building and the lawn on either side too, showed signs of neglect.
Swaroop took Nikhil inside, through a corridor and into a huge hall. There were several beds in the hall. In one corner were a few chairs facing a table on which a small TV set was placed. He looked around. He could see only old men. Some of them were sitting in chairs staring blankly into space, while others were lying down.
He couldn't see Baba.
"Daddy where is Baba?"
"There at the end. His bed is right next to the window. I requested Mr.Wadia to give him the best bed."
Nikhil looked towards where his father was pointing. Baba was standing by the bed looking out.
"Baba," Nikhil shouted rushing forward.
Gautam turned at the sound of the sweetest voice in the world.
Nikhil came hurtling into his arms. Gautam hugged him close.
An hour later, Swaroop told Nikhil. "Come on Nikhil let's go. Baba needs to take rest."
"But Daddy, we have just come."
"We have already spent more than and hour here. We can't stay anymore."
"Daddy I'll stay here with Baba, you go. I promise I won't bother him at all."
"You can't do that Nikhil it is not allowed."
Reluctantly Nikhil took leave of his Baba, fighting to control his tears.
• • • • •
A year went by. Gradually Nikhil's visits grew more and more infrequent. The whole week he would look forward to Sunday. And that day invariably his Daddy would be busy with his office colleagues and his Mummy with her friends. One day he had thrown a tantrum and had been thoroughly spanked by his father. After that he had stopped asking.
One evening Rina and Swaroop were sitting in their living room. It was eight and Nikhil had already slept.
"Swaroop today I had gone to Nikhil's school to attend the Parents- Teachers meeting," Rina said.
Swaroop was reading the newspaper. "Yes, " he mumbled.
"Nikhil is not doing well in the class."
"He is still young, he will improve."
"Come on Swaroop, in his class, everyone is equally young. But they are all able to cope, except Nikhil."
"Swaroop put down his paper. "What is the problem Rina? He has just gone to class two. You are acting as if he is preparing for his civil services. You should realise that there are some kids who are late starters. He will pick up."
"It is not as simple as that Swaroop. His teacher told me that he is totally non-communicative. He sits in one corner staring into space. He doesn't talk to anyone, doesn't participate in games. He doesn't seem to be following his lessons. His class work is never complete and his homework too hardly ever gets done."
"Why don't you engage a private tutor for him."
"Swaroop you seem to have forgotten. Three months back I engaged a young woman to teach him in Mrs. Desai's crèche itself. But even that did not help."
"So what do you want to do? If you have something in mind tell me."
"A few days back I discussed this problem with Mrs. Paliwal. She is one of our regular customers and likes me very much. She was suggesting that we take Nikhil to a pediatrician. She knows some one who is very good. She said she would get us an appointment with him."
"What's his name?"
"Dr. Utpal Nayak."
"I have of heard of him. Okay, Rina if you feel it really necessary let us consult him. As far as I am concerned I think all that Nikhil needs is some good old fashioned spanking. You have heard of the adage - 'Spare the rod and spoil the child'. I think we have been too soft on Nikhil."
"No, Swaroop, you are wrong. We should give this doctor a try."
"Okay, if you insist."
• • • • •
Three days later Rina and Swaroop were sitting in front of Dr. Nayak.
"Mr. and Mrs. Sharma , I have heard the entire case from you. But before I give my opinion I have to meet the boy. You should have brought him along with you."
"He is sitting outside Doctor. We didn't want to discuss his problems in his presence. Should I bring him?"
"Yes. And after a few minutes, when he settles down, you two leave. I want to talk to him alone."
Nikhil entered the room a trifle scared. Even though his mother had told him that he wouldn't be given an injection, he was apprehensive.
"Come, young man, come and sit beside me," Dr.Nayak said. He was a short completely bald man with a round, podgy face. He had small, bright eyes and was sporting a huge smile. Nikhil had imagined him to be a tall, grave looking man with a stethoscope hanging round his neck who would ask him to stick his tongue out, take a deep breath and at the first opportunity stick a couple of needles into him. He decided he quite liked this fellow, who looked more like an amiable halwai than a doctor.
"So, young man, what is your name?"
"Nikhil Mehrotra."
"Good. That's a lovely name. Remind me later I'll tell you a story about a young chap called Nikhil who was fond of eating pickle. Now I want to have a chat with you alone. Can I ask your Mummy - Papa to go?"
Nikhil nodded.
"You are sure you will not be scared to be alone with this huge, hefty dark and dangerous looking doctor?" Dr. Nayak asked, his eyes twinkling mischievously.
"No, "Nikhil said, smiling.
An hour later Nikhil came out of the room with Dr. Nayak in tow.
"Mr. Mehrotra, I have had a very nice time with Nikhil. He is a very smart boy and we have become good friends. I Would like to meet you tomorrow, same time. You need not bring Nikhil along. Poor fellow I think I have bored him enough today," Dr. Nayak said with a smile.
Next day Swaroop and Rina both went to Dr. Nayak's clinic.
"Mr. Mehrotra, the chat I had with Nikhil was very revealing. He is missing your father very much. Apparently he doesn't stay with you anymore. He left rather abruptly about a year and a half ago and is now staying in, from what I could gather from Nikhil version, in an old age home."
"Actually Doctor we had some family problems. Father didn't want to stay with us any longer. He left in a huff and shifted to 'Home and Hope'."
"I see. Anyway, Mr. Mehrotra you will have to somehow convince your father to come back and stay with you - atleast for a couple of years. You might not be realising, but the best kind of company a child can get is the company of his grandparents - particularly if they are free from other obligations. Your father had retired. His time and energy were all devoted to Nikhil. And the little fellow was really enjoying all the attention. The sweetest memories Nikhil has are of his grandpa,"
Dr. Nayak paused and peering intently at them continued, "Both of you are working. You simply have no time for him. And a crèche cannot be a substitute for the care , love and affection a grandparent can give. Try asking Nikhil. He simply hates going to the crèche."
"But Doctor we have our problems. You mean to say Rina should stop working and sit at home to take care of Nikhil."
"I am not suggesting that. I understand the circumstances are sometimes such that it becomes necessary for both parents to work.. I am not against that at all. I also have nothing against crèches, provided ofcourse they are managed properly. But in your case there is a vital difference. Nikhil was already used to his grandpa's company - a company he simply adored. That is why he is finding it so difficult to adjust in a crèche. At one stroke he was deprived of his mother's attention and his grandpa's love and care and was put in the alien atmosphere of the crèche. These things put together made him feel very insecure and that is the reason he has become withdrawn."
"But Doctor, suppose my father doesn't agree to come and stay with us."
"You have to persuade him for Nikhil's sake. Mr. Mehrotra this is my advice to all parents - working or otherwise - the greatest blessing any child can receive is the company of his grandparents. There is a saying in Hindi - 'The interest is always more attractive than the capital'. Similarly a grandparent is far fonder of his grandchild than he is of his son or daughter. If you study the interaction between these two generations you will agree with me. It is believed that old age is nothing but a second childhood. And in this second childhood a grandparent really enjoys being with his grandchild. And between a grandparent and a grandchild all that exists is pure, innocent love. I wouldn't for anything in the world deprive my child or my parents this pleasure."
"But Doctor suppose if the grandparents are not alive or are ill or are not able to live with their children for some reason or the other, than what?"
"Mr. Mehrotra, in that case the obvious choice is the crèche. But if you have parents who can stay with you than I think the first thing you should do is to get them to live with you. You cannot give your child a better gift than that company of his grandparents.
• • • • •
Two days later when Swaroop came to pick up Nikhil from the crèche he told him, "There is a surprise in store for you at home."
When they reached home and the door opened, Nikhil found his Baba standing there, arms outstretched. Nikhil couldn't believe his eyes. With a yell he jumped straight into Baba's arms and hugged him tightly.
• • • • •
Around six months later one day Gautam and Nikhil went to the market. As Gautam was buying medicines Nikhil saw Dr. Nayak.
"Doctor Uncle," he shouted running towards him. He caught hold of his hand and dragged him towards his grandfather.
"Doctor Uncle this is my Baba. And Baba this is the Doctor Uncle I was telling you about. He gave me that set of Panchatantra stories I was showing you yesterday.
"Mr. Mehrotra, it is really nice meeting you," Dr.Nayak said shaking hands with Gautam. "You know, I am really glad that you changed your mind and decided to come back and stay with your son."
"Changed my mind? I couldn't quite get you Dr. Nayak."
"Your son told me that you had shifted to 'Home and Hope' because of some personal problems. I had asked him to persuade you to come back, since Nikhil was missing you a lot. And see how right I was. After your homecoming he has shown tremendous improvement. Your son was telling me that Nikhil is doing much better in school."
Gautam kept silent. Later as they were walking back, he kept thinking about the Doctor's words. 'So Swaroop had told the Doctor that he, Gautam, had left home, while the truth was that he had been driven out. Moreover, Swaroop hadn't told him a word about Dr.Nayak's advice. He had simply said everyone at home, most of all Nikhil, was missing him, and would he please come back. Gautam had believed him and had been quite happy to return. Only now, after meeting the Doctor, he had realised that his son had lied to him. Swaroop's request was not because of a change of heart but because of the Doctor's advice. Anyway, there was nothing he could do about it. He had to continue staying with his son because of Nikhil. For his grandson's sake Gautam was willing to make every kind of adjustment.
• • • • •
A year went by. One day Gautam was sitting in the living room reading a book.
"Baba close your eyes." It was Nikhil. He had quietly entered the room and was standing in front of him with his hands behind his back.. Gautam shut his eyes.
A few seconds later Nikhil shouted, "Baba, now open your eyes."
On the table in front of Gautam was a brand new cup.
"Baba, I got it today."
"Its beautiful. Did you win a race?"
"No, Baba. There was a creative writing competition. I wrote a poem and recited it. I got the first prize. You want to listen to it?"
"Yes, Nikhil I would love to."
Nikhil got up, took a bow and began :
The title of the poem is : 'The Special Man in My Life':
I will tell you about someone.
Ten times as old as I,
Who has a heart that is
As large as the sky.
He tells me lovely stories
Almost every night,
And supports me whenever
With anyone I have a fight.
He is calm and cool
With lots of grace,
There is always a smile
On his handsome face.
Full of joy is he
And also very wise,
He appears to me
A Santa Clause in disguise.
I call him my Baba
I think he is truly great,
He has taught me always to love
And never ever to hate.
I love him much more
Than anyone ever can,
In my little life
He is the extra special man.
There is no place lovelier
On the world map,
Than my darling Baba's
Secure and safe lap
Without my dear Baba
I feel like an orphan,
In every birth of mine
Please God make me his grandson.
"How is it?" Nikhil asked. Gautam was unable to speak. Tears were flowing down his cheeks. He reached out for his grandson and drawing him close hugged him.
Gautam Mehrotra was sitting in the living room and reading the newspaper. It was a Sunday. He had just finished his breakfast and was trying to catch up with the rest of the world. Gautam had retired as a senior executive assistant in the Collector's office, after thirty one year's of service, ten month ago. Soon after retirement he had shifted bag and baggage from the district to his son Swaroop's house in the city. Swaroop was a cashier in the State Bank of India and lived in a tiny apartment with his wife Rina and son Nikhil. The flat had a living room, a bedroom, a kitchen and a small dining space. The cramped set up was on the third floor of a ten storied building.
Six year old Nikhil was very fond of his Baba and would sleep with him in the living room which was converted to a makeshift bedroom at night. Gautam too was enjoying his retirement life. He would play with Nikhil, tell him stories, take him to the park or the nearby markets and sometimes read a bit. In the District, all alone, after the death of his wife three years back, he had felt suffocated. But here with Nikhil for company he felt comfortable and relaxed.
"Babuji, I want to discuss something with you," Gautam looked up. Swaroop was standing with a worried expression on his face."
"Sure Roop come and sit." Swaroop sat down and kept looking at the ground. It was clear that he was feeling uneasy. Gautam looked at his tense face and asked him gently.
"What happened Roop? You look very serious. Is anything the matter?"
"Babuji, actually there is a problem. Rina has got a job as a saleswoman in a boutique."
"A saleswoman? But why?
"We need the money. The way the cost of living is shooting up we will not be able to manage only on one income. Nikhil is growing up. I want to give him the best education. Where am I going to get the money from? The three hundred rupees which you give every month too just disappears. I am hardly able to save anything."
"But surely you could have thought of a better job, a job which is less taxing."
"Babuji, you know jobs don't grow on trees. Rina is not even a graduate. Where is she going to get a job of her choice. We have to grab whatever is available."
"But Roop how will the poor girl manage her job and her housework?"
"That is where we need your help."
"Sure. I'll do whatever I can."
"Babuji, Rina will have to leave at nine thirty and will reach home only by around seven thirty. She will not be able to cook lunch or serve you the evening tiffin."
"No problem, Roop. She can make some extra rotis and sabzi. I'll have the same things for breakfast as well as lunch. As far as the evening tiffin is concerned, I'll make a light snack for myself. You don't bother about me. I can take care of myself. What I am worried about is Nikhil. You know how fussy he is about food."
"I have thought about that Babuji. Rina has talked to Mrs. Desai who runs a crèche in the opposite building on the second floor. She has agreed to admit Nikhil. In the morning, as usual, I will drop Nikhil in his school. At 2 p.m. when the school closes Nikhil will go in the same rickshaw, which he uses now, to go to the crèche. In the evening, by around six thirty I will pick him up. Nikhil will have his breakfast at home and lunch and evening tiffin in the crèche."
"But Roop, if Nikhil spends the whole day in the school and crèche , what will I do? I'll go mad just sitting at home all alone."
"I was thinking.....I... feel....," Swaroop hesitated and then said in a rush, "Babuji, there is a very good institution in our city. It is called 'Home and Hope'. It is run by an elderly Parsi couple - Mr. and Mrs. Wadia. I feel that you will be far more comfortable there. You will have good company - people of your age. I have been there. It is very nice place - neat, clean and well maintained. Its not very expensive. The three hundred rupees which you give me every month will be sufficient. And in case you need anything I am always there. And one more advantage is that there are quite a few diabetics there. The people who manage are used to preparing a diabetic's diet. So you shouldn't be having any problem. And Babuji, with Nikhil in the crèche and you in 'Home and Hope' Rina and I will be assured that the two of you are being taken care of and will be able to concentrate on our careers."
Swaroop stopped and looked at his father. Gautam was too shocked to say anything. He just sat in stunned silence: 'His only son wanted to dump him in an old age home'.
"When do you want me to leave," asked Gautam, his voice, his face giving no indication of his feelings.
"Rina has to report for duty next Monday, so I'll shift you the coming Sunday. And Babuji you need not worry about anything. Both Rina and I will be coming regularly to see you, along with Nikhil. I'll also be in touch with you over phone. I am sure you will like the place."
• • • • •
Nikhil was feeling miserable. He was sitting in the crèche staring blankly into space. Desai Aunty and her maidservant Tulasi were busy watching a serial on Zee TV. Debu, Rosy and Jay were playing cricket on the terrace while Munni and Vinil, the younger ones, were sleeping in the bedroom. Debu was older to Nikhil while Rosy and Jay were the same age. Debu was a bully and would keep pulling Nikhil's ears and calling him silly names. The other two would join him in making fun of Nikhil.
Nikhil hated going to the crèche. Desai Aunty was rude and Tulasi very nasty. The food Desai aunty cooked also tasted horrible. He had complained to mummy but she only scolded him. "Nikhil, you have to learn to adjust. You can not always get everything you want. And anyway you are having only lunch and a little bit of tiffin there. For breakfast and dinner I'll make things of your choice, okay?"
He had nodded his head.
One day mummy had given him two boondi laddus and an apple. Tulasi had given the apple to him and hogged the laddus herself. Nikhil had told mummy and she had spoken to Desai aunty. A few days, in the afternoon, when Desai aunty was sleeping Tulasi had confronted Nikhil. "You little runt. How dare you complain about me. Next time you squeal I'll tell my brother Rana who is a dada. He'll give you such a thrashing you will forget about Daddy, Mummy and everyone else.
Nikhil was terrified. After that whenever his parents asked him whether he had any problems in the crèche he said no.
At home too he felt very lonely. He missed his Baba very much. He had suddenly left him and gone somewhere. He still remembered that day very clearly. It was a Sunday and he had found Baba packing his bags.
"Baba are we going somewhere? Are we going to Bua Dadi's house?"
Baba's sister lived in a village on the outskirts of the city. Baba had taken him once there. They had spent three days and Nikhil had really enjoyed himself. Bua Dadi had made lovely things for him to eat - kheer, gajar halwa, hot samosas.....
"No, Nikhil, we are not going, I am going."
"Where Baba? Take me with you, please ."
His father had entered the room just then. "You can't go with him, Nikhil."
"Why?"
"Like you go to school Baba is going to his school."
"You are lying Daddy. How can Baba go to school. He is not a small boy."
"Yes, son, I know he is not a small boy. That is why he is going to a school which is meant for old people."
Confused Nikhil looked at Baba. But Baba continued his packing without looking at him. Nikhil knew something was wrong. He went into the kitchen and asked his mummy, but she too was evasive.
He went back and asked Baba. "When will you come back?"
"I...I can't say son," Baba replied, not meeting his eyes.
"We'll go and visit him every week," Daddy told Nikhil.
Just before Baba sat in the auto, he picked up Nikhil and hugged him. Nikhil clung to him and started sobbing. Very reluctantly Baba handed Nikhil to his mother and wiping his eyes got into the auto.
That night Nikhil refused to sleep alone in the living room. Finally after a lot of shouting and screaming he was allowed to sleep with his parents in the bedroom. However, in the middle of the night when he woke up he found himself all alone in the living room. He looked around for Baba, but he was not there. Then he remembered, his Baba had left him and gone away to his school. He started sobbing loudly. A few minutes later his mother came and took him inside. He still couldn't sleep for hours. He just clung to his mother and cried his heart out.
The next few days Nikhil insisted he would sleep with his parents. One evening his father told him, "Son you are now a young man. You have to learn to be brave. If you get scared like this everyone will call you a sissy."
"But Daddy without Baba I feel very lonely. I keep thinking about him and start crying..... and..... and Daddy when the lights are switched off I also get scared."
"Nikhil you should not behave like a cry baby. You want to meet Baba, don't you?"
"Yes," Nikhil said his face lighting up.
"Well then if you agree to sleep alone I will take you to meet your Baba this Sunday."
Nikhil quietly got up, picked up his pillow and went to the living room. There he planked himself on the sofa and tried to sleep....
• • • • •
Sunday morning Nikhil got up feeling very excited. Today he would be meeting Baba. He quickly brushed his teeth, took a bath, ate breakfast and drank his milk without any fuss. By nine he was ready.
"Daddy, I am ready. Let us go."
Swaroop was watching the serial Chandrakanta on TV. "Go where?"
"To see Baba. Have you forgotten? You promised to take me to meet Baba. I am ready. Let's go."
"This early? Don't be silly Nikhil. Can't you see I am busy now? Moreover after watching this serial I have to go to Mirza Uncle's house. I'll take you in the evening."
Nikhil's face fell. He was really disappointed. He wanted to protest, but he was scared. Daddy might get angry and not take him at all.
At five in the evening Swaroop took Nikhil on his scooter. After travelling for almost an hour they reached a building at the end of a lonely road. It had a compound wall with an iron gate. They went in. The building was quite badly maintained with cracks in the walls and the paint peeling off. The pathway to the building and the lawn on either side too, showed signs of neglect.
Swaroop took Nikhil inside, through a corridor and into a huge hall. There were several beds in the hall. In one corner were a few chairs facing a table on which a small TV set was placed. He looked around. He could see only old men. Some of them were sitting in chairs staring blankly into space, while others were lying down.
He couldn't see Baba.
"Daddy where is Baba?"
"There at the end. His bed is right next to the window. I requested Mr.Wadia to give him the best bed."
Nikhil looked towards where his father was pointing. Baba was standing by the bed looking out.
"Baba," Nikhil shouted rushing forward.
Gautam turned at the sound of the sweetest voice in the world.
Nikhil came hurtling into his arms. Gautam hugged him close.
An hour later, Swaroop told Nikhil. "Come on Nikhil let's go. Baba needs to take rest."
"But Daddy, we have just come."
"We have already spent more than and hour here. We can't stay anymore."
"Daddy I'll stay here with Baba, you go. I promise I won't bother him at all."
"You can't do that Nikhil it is not allowed."
Reluctantly Nikhil took leave of his Baba, fighting to control his tears.
• • • • •
A year went by. Gradually Nikhil's visits grew more and more infrequent. The whole week he would look forward to Sunday. And that day invariably his Daddy would be busy with his office colleagues and his Mummy with her friends. One day he had thrown a tantrum and had been thoroughly spanked by his father. After that he had stopped asking.
One evening Rina and Swaroop were sitting in their living room. It was eight and Nikhil had already slept.
"Swaroop today I had gone to Nikhil's school to attend the Parents- Teachers meeting," Rina said.
Swaroop was reading the newspaper. "Yes, " he mumbled.
"Nikhil is not doing well in the class."
"He is still young, he will improve."
"Come on Swaroop, in his class, everyone is equally young. But they are all able to cope, except Nikhil."
"Swaroop put down his paper. "What is the problem Rina? He has just gone to class two. You are acting as if he is preparing for his civil services. You should realise that there are some kids who are late starters. He will pick up."
"It is not as simple as that Swaroop. His teacher told me that he is totally non-communicative. He sits in one corner staring into space. He doesn't talk to anyone, doesn't participate in games. He doesn't seem to be following his lessons. His class work is never complete and his homework too hardly ever gets done."
"Why don't you engage a private tutor for him."
"Swaroop you seem to have forgotten. Three months back I engaged a young woman to teach him in Mrs. Desai's crèche itself. But even that did not help."
"So what do you want to do? If you have something in mind tell me."
"A few days back I discussed this problem with Mrs. Paliwal. She is one of our regular customers and likes me very much. She was suggesting that we take Nikhil to a pediatrician. She knows some one who is very good. She said she would get us an appointment with him."
"What's his name?"
"Dr. Utpal Nayak."
"I have of heard of him. Okay, Rina if you feel it really necessary let us consult him. As far as I am concerned I think all that Nikhil needs is some good old fashioned spanking. You have heard of the adage - 'Spare the rod and spoil the child'. I think we have been too soft on Nikhil."
"No, Swaroop, you are wrong. We should give this doctor a try."
"Okay, if you insist."
• • • • •
Three days later Rina and Swaroop were sitting in front of Dr. Nayak.
"Mr. and Mrs. Sharma , I have heard the entire case from you. But before I give my opinion I have to meet the boy. You should have brought him along with you."
"He is sitting outside Doctor. We didn't want to discuss his problems in his presence. Should I bring him?"
"Yes. And after a few minutes, when he settles down, you two leave. I want to talk to him alone."
Nikhil entered the room a trifle scared. Even though his mother had told him that he wouldn't be given an injection, he was apprehensive.
"Come, young man, come and sit beside me," Dr.Nayak said. He was a short completely bald man with a round, podgy face. He had small, bright eyes and was sporting a huge smile. Nikhil had imagined him to be a tall, grave looking man with a stethoscope hanging round his neck who would ask him to stick his tongue out, take a deep breath and at the first opportunity stick a couple of needles into him. He decided he quite liked this fellow, who looked more like an amiable halwai than a doctor.
"So, young man, what is your name?"
"Nikhil Mehrotra."
"Good. That's a lovely name. Remind me later I'll tell you a story about a young chap called Nikhil who was fond of eating pickle. Now I want to have a chat with you alone. Can I ask your Mummy - Papa to go?"
Nikhil nodded.
"You are sure you will not be scared to be alone with this huge, hefty dark and dangerous looking doctor?" Dr. Nayak asked, his eyes twinkling mischievously.
"No, "Nikhil said, smiling.
An hour later Nikhil came out of the room with Dr. Nayak in tow.
"Mr. Mehrotra, I have had a very nice time with Nikhil. He is a very smart boy and we have become good friends. I Would like to meet you tomorrow, same time. You need not bring Nikhil along. Poor fellow I think I have bored him enough today," Dr. Nayak said with a smile.
Next day Swaroop and Rina both went to Dr. Nayak's clinic.
"Mr. Mehrotra, the chat I had with Nikhil was very revealing. He is missing your father very much. Apparently he doesn't stay with you anymore. He left rather abruptly about a year and a half ago and is now staying in, from what I could gather from Nikhil version, in an old age home."
"Actually Doctor we had some family problems. Father didn't want to stay with us any longer. He left in a huff and shifted to 'Home and Hope'."
"I see. Anyway, Mr. Mehrotra you will have to somehow convince your father to come back and stay with you - atleast for a couple of years. You might not be realising, but the best kind of company a child can get is the company of his grandparents - particularly if they are free from other obligations. Your father had retired. His time and energy were all devoted to Nikhil. And the little fellow was really enjoying all the attention. The sweetest memories Nikhil has are of his grandpa,"
Dr. Nayak paused and peering intently at them continued, "Both of you are working. You simply have no time for him. And a crèche cannot be a substitute for the care , love and affection a grandparent can give. Try asking Nikhil. He simply hates going to the crèche."
"But Doctor we have our problems. You mean to say Rina should stop working and sit at home to take care of Nikhil."
"I am not suggesting that. I understand the circumstances are sometimes such that it becomes necessary for both parents to work.. I am not against that at all. I also have nothing against crèches, provided ofcourse they are managed properly. But in your case there is a vital difference. Nikhil was already used to his grandpa's company - a company he simply adored. That is why he is finding it so difficult to adjust in a crèche. At one stroke he was deprived of his mother's attention and his grandpa's love and care and was put in the alien atmosphere of the crèche. These things put together made him feel very insecure and that is the reason he has become withdrawn."
"But Doctor, suppose my father doesn't agree to come and stay with us."
"You have to persuade him for Nikhil's sake. Mr. Mehrotra this is my advice to all parents - working or otherwise - the greatest blessing any child can receive is the company of his grandparents. There is a saying in Hindi - 'The interest is always more attractive than the capital'. Similarly a grandparent is far fonder of his grandchild than he is of his son or daughter. If you study the interaction between these two generations you will agree with me. It is believed that old age is nothing but a second childhood. And in this second childhood a grandparent really enjoys being with his grandchild. And between a grandparent and a grandchild all that exists is pure, innocent love. I wouldn't for anything in the world deprive my child or my parents this pleasure."
"But Doctor suppose if the grandparents are not alive or are ill or are not able to live with their children for some reason or the other, than what?"
"Mr. Mehrotra, in that case the obvious choice is the crèche. But if you have parents who can stay with you than I think the first thing you should do is to get them to live with you. You cannot give your child a better gift than that company of his grandparents.
• • • • •
Two days later when Swaroop came to pick up Nikhil from the crèche he told him, "There is a surprise in store for you at home."
When they reached home and the door opened, Nikhil found his Baba standing there, arms outstretched. Nikhil couldn't believe his eyes. With a yell he jumped straight into Baba's arms and hugged him tightly.
• • • • •
Around six months later one day Gautam and Nikhil went to the market. As Gautam was buying medicines Nikhil saw Dr. Nayak.
"Doctor Uncle," he shouted running towards him. He caught hold of his hand and dragged him towards his grandfather.
"Doctor Uncle this is my Baba. And Baba this is the Doctor Uncle I was telling you about. He gave me that set of Panchatantra stories I was showing you yesterday.
"Mr. Mehrotra, it is really nice meeting you," Dr.Nayak said shaking hands with Gautam. "You know, I am really glad that you changed your mind and decided to come back and stay with your son."
"Changed my mind? I couldn't quite get you Dr. Nayak."
"Your son told me that you had shifted to 'Home and Hope' because of some personal problems. I had asked him to persuade you to come back, since Nikhil was missing you a lot. And see how right I was. After your homecoming he has shown tremendous improvement. Your son was telling me that Nikhil is doing much better in school."
Gautam kept silent. Later as they were walking back, he kept thinking about the Doctor's words. 'So Swaroop had told the Doctor that he, Gautam, had left home, while the truth was that he had been driven out. Moreover, Swaroop hadn't told him a word about Dr.Nayak's advice. He had simply said everyone at home, most of all Nikhil, was missing him, and would he please come back. Gautam had believed him and had been quite happy to return. Only now, after meeting the Doctor, he had realised that his son had lied to him. Swaroop's request was not because of a change of heart but because of the Doctor's advice. Anyway, there was nothing he could do about it. He had to continue staying with his son because of Nikhil. For his grandson's sake Gautam was willing to make every kind of adjustment.
• • • • •
A year went by. One day Gautam was sitting in the living room reading a book.
"Baba close your eyes." It was Nikhil. He had quietly entered the room and was standing in front of him with his hands behind his back.. Gautam shut his eyes.
A few seconds later Nikhil shouted, "Baba, now open your eyes."
On the table in front of Gautam was a brand new cup.
"Baba, I got it today."
"Its beautiful. Did you win a race?"
"No, Baba. There was a creative writing competition. I wrote a poem and recited it. I got the first prize. You want to listen to it?"
"Yes, Nikhil I would love to."
Nikhil got up, took a bow and began :
The title of the poem is : 'The Special Man in My Life':
I will tell you about someone.
Ten times as old as I,
Who has a heart that is
As large as the sky.
He tells me lovely stories
Almost every night,
And supports me whenever
With anyone I have a fight.
He is calm and cool
With lots of grace,
There is always a smile
On his handsome face.
Full of joy is he
And also very wise,
He appears to me
A Santa Clause in disguise.
I call him my Baba
I think he is truly great,
He has taught me always to love
And never ever to hate.
I love him much more
Than anyone ever can,
In my little life
He is the extra special man.
There is no place lovelier
On the world map,
Than my darling Baba's
Secure and safe lap
Without my dear Baba
I feel like an orphan,
In every birth of mine
Please God make me his grandson.
"How is it?" Nikhil asked. Gautam was unable to speak. Tears were flowing down his cheeks. He reached out for his grandson and drawing him close hugged him.
Title.
JENIS-JENIS MEDIA PENYIMPANAN
* Cache Memory
* Main Memory
* Flash Memory
* Magnetic Disc Storage
* Optical Storage
* Tape Storage
* RAID
GAMBARAN UMUM BENTUK FISIK
Terdapat beberapa tipe media penyimpanan data pada sistem komputer. Penyimpanan data dibedakan berdasarkan :
* Kecepatan Akses Data
* Harga dari Media Penyimpanan
* Kehandalan dari Media Penyimpanan
Media penyimpanan informasi di system computer dibagi menjadi 2 tipe utama :
Penyimpan primer / Primary Storage. Ciri-ciri :
* Kecepatan akses tinggi
* Harganya relative mahal
* Kapasitas relative kecil
* Volatile
Penyimpan sekunder / Secondary Storage. Ciri-ciri :
* Kecepatan akses rendah
* Harganya relative murah
* Kapasitas relative besar
* Non-volatile
CACHE MEMORY
* Chache Memory mempunyai akses data paling cepat
* Cache Memory merupakan penyimpanan paling mahal
* Kapasitas Cache Memory paling Kecil (mis 256 KB – I MB)
* Mempunyai sifat volatile
* Cache Memory biasanya terletak pada Mainboard
* Biasanya prosessor akan mencari data pada cache memory dulu sebelum mencari data data memory utama
* Biasanya data yang terletak pada cache memory adalah data yang sering di baca
MAIN MEMORY (RAM)
* Merupakan simpanan data pada saat komputer beroperasi
* Harganya relatif masih mahal
* Kapasitas relatif kecil ( mis 64 MB – 1 GB)
* Kecepatan akses relatif lebih cepat
* Bersifat volatile
FLASH MEMORY
* Merupakan simpanan data yang banyak digunakan saat ini
* Menggunakan cara kerja EEPROM (electrically eraseable programmable read only memory)
* Kapasitas relatif lebih kecil besar dibandingkan main memory
* Non-volatile
* Kecepatan relatif lebih lambat dibandingkan main memory
MAGNETIC-DISC STORAGE
* Kapasitas relatif besar ( 1 GB – 100 GB)
* Kecepatan relatif lambat
* Harga Relatif Lebih murah
* Non-volatile
* Merupakan media penyimpanan yang paling banyak dipakai
* Kapasitas terus berkembang, karena aplikasi sistem komputer yang semakin berkembang
* Database yang besar biasanya membutuhkan lebih dari 1 hard disk untuk penyimpanannya
* Phisik sebuah hardisk terbuat dari bahan Magnetic disk terbuat dari sejumlah plat/cakram. Permukaan tiap cakram (atas/bawah) terbuat dari bahan besi yang mudah dimagnetisasi
* Perekaman data
* Pada disk magnetic kode on dan off direpresentasikan oleh kedudukan elemen magnetiknya
* Dengan mengimbas permukaan disk dengan magnet (yang ada pada head), kedudukan elemen magnet berubah. Artinya kode on bisa diganti off dan sebaliknya
* Lubang-lubang di permukaan disk merepresentasikan data yang tersusun dalam suatu jalur yang disebut track. Data disimpan dalam track yang berbentuk konsentris
* Tiap track dibagi menjadi sector-sektor (blok)
* Magnetic disk diorganisasikan menjadi silinder-silinder
* Silinder adalah track-track yang sama pada permukaan-permukaan pada cakram-cakram yang berbeda
* Head R/W menyimpan informasi yang diambil dari magnetisasi sektor-sektor yang ada dibawahnya
* Head R/W melayang di atas permukaan platter
* Jika Head R/W menyentuh permukaan plat, maka data yang ada di bawahnya akan rusak
* Disc Controller merupakan interface antar sistem komputer dan hardware dari hardisk dengan menerima perintah read / write pada sebuah sector
* Disc controller juga bertugas untuk remapping bad sector, sehingga data tidak disimpan pada bad sektor pada hard disk
* Kapasitas
* Waktu akses (access time) : waktu mulai permintaan read/write hingga transfer data dimulai
* Rata-rata waktu transfer data (data-transfer rate) : waktu rata-rata data diambil atau disimpan ke dalam hardisk ( mis 4 – 8 MB per detik)
* Reliability
* Proses I/O pada disk ditentukan oleh sistem operasi
* Setiap proses I/O akan meminta alamat dari data pada harddisk, yang disebut juga block number (nomor blok)
* Ukuran blok berkisar dari 512 kb – 4096 kb
* Data ditransfer antara memory dan hardisk dalam ukuran blok
* Karena akses data pada hardisk lebih lambat dibanding dengan akses data pada memory, maka sering terjadi bottleneck
* Pengembangan dilakukan pada teknik untuk memperbaiki kecepatan akses blok pada disk
Waktu Akses terdiri dari :
* SEEK TIME : Waktu yang dibutuhkan untuk menempatkan R/W head pada cylinder yang diinginkan ( mis 2 – 30 millisecond)
* ROTATIONAL LATENCY TIME : Waktu yang dibutuhkan untuk menunggu sampai data berada di bawah R/W head. Biasanya sekitas 5400 RPM – 15000 RPM
Beberapa teknik yang dikembangkan dalam perbaikan kecepatan access blok pada disk :
* Scheduling (penjadwalan)
* File organization (organisasi file)
* Non-volatile write buffers (penulisan pada buffer non-volatile)
* Log disk
OPTICAL STORAGE
* Simpanan data pengganti disket ( mudah dibawa-bawa)
* Kapasitas relatif besar ( 1 keping CD dapat menyimpan s/d 640 MB, 1 keping DVD dapat menyimpan s/d 1,7 GB)
* Kecepatan relatif lebih lambat
* Harga relatif lebih murah
* Non-Volatile
TAPE STORAGE
* Kapasitas sangat besar ( 40 GB – 400 GB)
* Kecepatan akses paling lambat
* Non-Volatile
* Harga paling murah
* Biasa digunakan untuk back up data
HIRARKI MEDIA PENYIMPANAN DATA
Hirarki Media Penyimpanan Data
Hirarki Media Penyimpanan Data
Urutan media penyimpanan dari yang tercepat :
* Primary storage
* Cache memory, main memory
* Secondary storage (online storage)
* Magnetic disc
* Tertiary storage (off line storage)
* Optical disc, magnetic tape
RAID
Raid ( redundant arrays of independent disks) : Satu set disk drive yang bekerja seolah-olah sebagai satu disk drive tunggal
Latar Belakang Raid :
* Kecepatan komputer tergantung dari kecepatan cpu, kecepatan memory dan kecepatan proses i/o
* Kecepatan memori dan processor berkembang cepat
* Kecepatan proses i/o berkembang lambat
Blok-blok data disebut page-page data disimpan dalam pola pita-pita (stripes)
TIGA KARAKTERISTIK UMUM DARI RAID INI, YAITU:
* Menurut stallings [stallings2001], raid adalah sebuah set dari beberapa physical drive yang dipandang oleh sistem operasi sebagai sebuah logical drive
* Data didistribusikan ke dalam array dari beberapa physical drive
* Kapasitas disk yang berlebih digunakan untuk menyimpan informasi paritas, yang menjamin data dapat diperbaiki jika terjadi kegagalan pada salah satu disk
RAID
RAID
Kerusakan beberapa disk yang dijadikan satu lebih besar dibandingkan dengan kerusakan satu disk. Mis : mttf disk 100.000 jam ( 11 tahun), jika 100 disk dijadikan satu maka mttf menjadi 100.000 / 100 = 1000 jam ( 42 hari).
note : MTTF =Mean Time to Failure
Solusi untuk permasalahan di atas adalah dengan membuat duplikasi disk, menyimpan data yang sama pada dua disk yang berbeda, sehingga jika data rusak pada disk yang satu, maka data pada disk yang lain dapat diselamatkan (teknik ini disebut mirroring atau shadowing).
Duplikasi Data
Duplikasi Data
MTTF pada disk yang menggunakan mirorring tergantung dari mttf masing-masing disk. Serta tergantung dari MTTR (mean time to repair) ( waktu yang dibutuhkan untuk mengganti disk yang rusak dan untuk memperbaiki data pada disk tersebut) .
Misal: 2 buah disk, MTTF masing-masing disk = 100.000 jam dan mean time to repair = 10 jam maka mean time terhadap kehilangan data pada disk yang menggunakan mirroring adalah 1000002 / (2 * 10) = 500 x 106 jam atau sekitar 57.000 tahun.
Kerusakan pada disk yang diduplikasi dapat terjadi karena arus listrik yang terputus atau bencana alam (banjir, kebakaran atau gempa bumi).
Biasanya kerusakan yang disebabkan arus listrik menyebabkan data yang langsung direkam pada dua disk tsb akan rusak. Hal ini dapat disiasati dengan cara data direkam pada disk yang satu, setelah selesai baru kemudian data direkam pada disk yang lain.
PERBAIKAN PERFORMANCE DISK MELALUI PARALLELISM :
* Menggunakan disk lebih dari satu dapat mempercepat waktu transfer data dengan cara stripping data (blok-blok ) data disimpan pada disk yang berbeda
* Bit level stripping : tiap bit direkam pada disk yang berbeda
* Blok level stripping : tiap blok direkam pada disk yang berbeda
Yang Paling Banyak Digunakan Adalah Blok Level Stripping.
Block Level Stripping
Block Level Stripping
LEVEL RAID
* Mirroring memperbaiki kehandalan tapi sangat mahal
* Stripping memperbaiki rata-rata waktu transfer tapi tidak memperbaiki kehandalan
* Macam-macam alternatif dibuat untuk membuat duplikasi dengan biaya yang murah dengan mengkombinasikan tripping dengan parity bit
* Alternatif tersebut digambarkan dengan cara membuat level-level raid
RAID 0
RAID 0
RAID 1
RAID 1
RAID 2
RAID 2
RAID 3
RAID 3
RAID 4
RAID 4
RAID 5
RAID 5
Faktor-faktor Yang Mempengaruhi Level Raid :
* Faktor keuangan untuk permintaan jumlah disk yang banyak
* Performance Dari Operasi I/O
* Performance pada saat disk mengalami kerusakan (Tergantung dari MTTF)
* Performance selama data pada disk yang satu rusak, data pada disk yang lain direbuilt (bangun kembali) (tergantung MTTR)
MASALAH HARDWARE :
* Raid dapat diimplementasi tanpa ada perubahan pada level hardware, hanya merubah dengan software (software raid)
* Ada keuntungan lebih jika dibuat hardware yang secara khusus digunakan untuk mendukung raid (hardware raid)
* Implementasinya pada penggunaan ram non-volatile untuk merekam data yang akan ditulis, jika listrik mati sebelum proses perekaman selesai, maka sistem dapat mengambil informasi pada ram tsb untuk menyelesaikan perekaman
* Cache Memory
* Main Memory
* Flash Memory
* Magnetic Disc Storage
* Optical Storage
* Tape Storage
* RAID
GAMBARAN UMUM BENTUK FISIK
Terdapat beberapa tipe media penyimpanan data pada sistem komputer. Penyimpanan data dibedakan berdasarkan :
* Kecepatan Akses Data
* Harga dari Media Penyimpanan
* Kehandalan dari Media Penyimpanan
Media penyimpanan informasi di system computer dibagi menjadi 2 tipe utama :
Penyimpan primer / Primary Storage. Ciri-ciri :
* Kecepatan akses tinggi
* Harganya relative mahal
* Kapasitas relative kecil
* Volatile
Penyimpan sekunder / Secondary Storage. Ciri-ciri :
* Kecepatan akses rendah
* Harganya relative murah
* Kapasitas relative besar
* Non-volatile
CACHE MEMORY
* Chache Memory mempunyai akses data paling cepat
* Cache Memory merupakan penyimpanan paling mahal
* Kapasitas Cache Memory paling Kecil (mis 256 KB – I MB)
* Mempunyai sifat volatile
* Cache Memory biasanya terletak pada Mainboard
* Biasanya prosessor akan mencari data pada cache memory dulu sebelum mencari data data memory utama
* Biasanya data yang terletak pada cache memory adalah data yang sering di baca
MAIN MEMORY (RAM)
* Merupakan simpanan data pada saat komputer beroperasi
* Harganya relatif masih mahal
* Kapasitas relatif kecil ( mis 64 MB – 1 GB)
* Kecepatan akses relatif lebih cepat
* Bersifat volatile
FLASH MEMORY
* Merupakan simpanan data yang banyak digunakan saat ini
* Menggunakan cara kerja EEPROM (electrically eraseable programmable read only memory)
* Kapasitas relatif lebih kecil besar dibandingkan main memory
* Non-volatile
* Kecepatan relatif lebih lambat dibandingkan main memory
MAGNETIC-DISC STORAGE
* Kapasitas relatif besar ( 1 GB – 100 GB)
* Kecepatan relatif lambat
* Harga Relatif Lebih murah
* Non-volatile
* Merupakan media penyimpanan yang paling banyak dipakai
* Kapasitas terus berkembang, karena aplikasi sistem komputer yang semakin berkembang
* Database yang besar biasanya membutuhkan lebih dari 1 hard disk untuk penyimpanannya
* Phisik sebuah hardisk terbuat dari bahan Magnetic disk terbuat dari sejumlah plat/cakram. Permukaan tiap cakram (atas/bawah) terbuat dari bahan besi yang mudah dimagnetisasi
* Perekaman data
* Pada disk magnetic kode on dan off direpresentasikan oleh kedudukan elemen magnetiknya
* Dengan mengimbas permukaan disk dengan magnet (yang ada pada head), kedudukan elemen magnet berubah. Artinya kode on bisa diganti off dan sebaliknya
* Lubang-lubang di permukaan disk merepresentasikan data yang tersusun dalam suatu jalur yang disebut track. Data disimpan dalam track yang berbentuk konsentris
* Tiap track dibagi menjadi sector-sektor (blok)
* Magnetic disk diorganisasikan menjadi silinder-silinder
* Silinder adalah track-track yang sama pada permukaan-permukaan pada cakram-cakram yang berbeda
* Head R/W menyimpan informasi yang diambil dari magnetisasi sektor-sektor yang ada dibawahnya
* Head R/W melayang di atas permukaan platter
* Jika Head R/W menyentuh permukaan plat, maka data yang ada di bawahnya akan rusak
* Disc Controller merupakan interface antar sistem komputer dan hardware dari hardisk dengan menerima perintah read / write pada sebuah sector
* Disc controller juga bertugas untuk remapping bad sector, sehingga data tidak disimpan pada bad sektor pada hard disk
* Kapasitas
* Waktu akses (access time) : waktu mulai permintaan read/write hingga transfer data dimulai
* Rata-rata waktu transfer data (data-transfer rate) : waktu rata-rata data diambil atau disimpan ke dalam hardisk ( mis 4 – 8 MB per detik)
* Reliability
* Proses I/O pada disk ditentukan oleh sistem operasi
* Setiap proses I/O akan meminta alamat dari data pada harddisk, yang disebut juga block number (nomor blok)
* Ukuran blok berkisar dari 512 kb – 4096 kb
* Data ditransfer antara memory dan hardisk dalam ukuran blok
* Karena akses data pada hardisk lebih lambat dibanding dengan akses data pada memory, maka sering terjadi bottleneck
* Pengembangan dilakukan pada teknik untuk memperbaiki kecepatan akses blok pada disk
Waktu Akses terdiri dari :
* SEEK TIME : Waktu yang dibutuhkan untuk menempatkan R/W head pada cylinder yang diinginkan ( mis 2 – 30 millisecond)
* ROTATIONAL LATENCY TIME : Waktu yang dibutuhkan untuk menunggu sampai data berada di bawah R/W head. Biasanya sekitas 5400 RPM – 15000 RPM
Beberapa teknik yang dikembangkan dalam perbaikan kecepatan access blok pada disk :
* Scheduling (penjadwalan)
* File organization (organisasi file)
* Non-volatile write buffers (penulisan pada buffer non-volatile)
* Log disk
OPTICAL STORAGE
* Simpanan data pengganti disket ( mudah dibawa-bawa)
* Kapasitas relatif besar ( 1 keping CD dapat menyimpan s/d 640 MB, 1 keping DVD dapat menyimpan s/d 1,7 GB)
* Kecepatan relatif lebih lambat
* Harga relatif lebih murah
* Non-Volatile
TAPE STORAGE
* Kapasitas sangat besar ( 40 GB – 400 GB)
* Kecepatan akses paling lambat
* Non-Volatile
* Harga paling murah
* Biasa digunakan untuk back up data
HIRARKI MEDIA PENYIMPANAN DATA
Hirarki Media Penyimpanan Data
Hirarki Media Penyimpanan Data
Urutan media penyimpanan dari yang tercepat :
* Primary storage
* Cache memory, main memory
* Secondary storage (online storage)
* Magnetic disc
* Tertiary storage (off line storage)
* Optical disc, magnetic tape
RAID
Raid ( redundant arrays of independent disks) : Satu set disk drive yang bekerja seolah-olah sebagai satu disk drive tunggal
Latar Belakang Raid :
* Kecepatan komputer tergantung dari kecepatan cpu, kecepatan memory dan kecepatan proses i/o
* Kecepatan memori dan processor berkembang cepat
* Kecepatan proses i/o berkembang lambat
Blok-blok data disebut page-page data disimpan dalam pola pita-pita (stripes)
TIGA KARAKTERISTIK UMUM DARI RAID INI, YAITU:
* Menurut stallings [stallings2001], raid adalah sebuah set dari beberapa physical drive yang dipandang oleh sistem operasi sebagai sebuah logical drive
* Data didistribusikan ke dalam array dari beberapa physical drive
* Kapasitas disk yang berlebih digunakan untuk menyimpan informasi paritas, yang menjamin data dapat diperbaiki jika terjadi kegagalan pada salah satu disk
RAID
RAID
Kerusakan beberapa disk yang dijadikan satu lebih besar dibandingkan dengan kerusakan satu disk. Mis : mttf disk 100.000 jam ( 11 tahun), jika 100 disk dijadikan satu maka mttf menjadi 100.000 / 100 = 1000 jam ( 42 hari).
note : MTTF =Mean Time to Failure
Solusi untuk permasalahan di atas adalah dengan membuat duplikasi disk, menyimpan data yang sama pada dua disk yang berbeda, sehingga jika data rusak pada disk yang satu, maka data pada disk yang lain dapat diselamatkan (teknik ini disebut mirroring atau shadowing).
Duplikasi Data
Duplikasi Data
MTTF pada disk yang menggunakan mirorring tergantung dari mttf masing-masing disk. Serta tergantung dari MTTR (mean time to repair) ( waktu yang dibutuhkan untuk mengganti disk yang rusak dan untuk memperbaiki data pada disk tersebut) .
Misal: 2 buah disk, MTTF masing-masing disk = 100.000 jam dan mean time to repair = 10 jam maka mean time terhadap kehilangan data pada disk yang menggunakan mirroring adalah 1000002 / (2 * 10) = 500 x 106 jam atau sekitar 57.000 tahun.
Kerusakan pada disk yang diduplikasi dapat terjadi karena arus listrik yang terputus atau bencana alam (banjir, kebakaran atau gempa bumi).
Biasanya kerusakan yang disebabkan arus listrik menyebabkan data yang langsung direkam pada dua disk tsb akan rusak. Hal ini dapat disiasati dengan cara data direkam pada disk yang satu, setelah selesai baru kemudian data direkam pada disk yang lain.
PERBAIKAN PERFORMANCE DISK MELALUI PARALLELISM :
* Menggunakan disk lebih dari satu dapat mempercepat waktu transfer data dengan cara stripping data (blok-blok ) data disimpan pada disk yang berbeda
* Bit level stripping : tiap bit direkam pada disk yang berbeda
* Blok level stripping : tiap blok direkam pada disk yang berbeda
Yang Paling Banyak Digunakan Adalah Blok Level Stripping.
Block Level Stripping
Block Level Stripping
LEVEL RAID
* Mirroring memperbaiki kehandalan tapi sangat mahal
* Stripping memperbaiki rata-rata waktu transfer tapi tidak memperbaiki kehandalan
* Macam-macam alternatif dibuat untuk membuat duplikasi dengan biaya yang murah dengan mengkombinasikan tripping dengan parity bit
* Alternatif tersebut digambarkan dengan cara membuat level-level raid
RAID 0
RAID 0
RAID 1
RAID 1
RAID 2
RAID 2
RAID 3
RAID 3
RAID 4
RAID 4
RAID 5
RAID 5
Faktor-faktor Yang Mempengaruhi Level Raid :
* Faktor keuangan untuk permintaan jumlah disk yang banyak
* Performance Dari Operasi I/O
* Performance pada saat disk mengalami kerusakan (Tergantung dari MTTF)
* Performance selama data pada disk yang satu rusak, data pada disk yang lain direbuilt (bangun kembali) (tergantung MTTR)
MASALAH HARDWARE :
* Raid dapat diimplementasi tanpa ada perubahan pada level hardware, hanya merubah dengan software (software raid)
* Ada keuntungan lebih jika dibuat hardware yang secara khusus digunakan untuk mendukung raid (hardware raid)
* Implementasinya pada penggunaan ram non-volatile untuk merekam data yang akan ditulis, jika listrik mati sebelum proses perekaman selesai, maka sistem dapat mengambil informasi pada ram tsb untuk menyelesaikan perekaman
