The story of Timun Emas

One night Buto Ijo, a giant with supranatural powers,  passed a farmer’s house. He heard the farmer’s pray. “Don’t worry farmers. I can give you a child. But you have to give me that child when she is 17 years old,” said Buto Ijo. The farmers were so happy. They did not think about the risk of losing their child letter and agree to take the offer.

Later, Buto Ijo gave them a bunch of cucumber seeds. The farmers planted them carefully. Then the seeds changed into plants. No longer after that, a big golden cucumber grew from plants. After it had ripe, the farmers picked and cut it. They were very surprised to see beautiful girl inside the cucumber. They named her Timun Mas or Golden Cucumber. Years passed by and Timun Mas has changed into a beautiful girl. On her 17th birthday, Timun Mas was very happy.

contoh t narrative dalm cerita rakyat timun emast
Cerita Timun Emas sebagai contoh text narrative
However, the parents were very sad. They knew they had to keep their promise to Buto Ijo the giant but they also did not want to lose their beloved daughter. “My daughter, take this bag. It can save you from the giant,” said father. “What do you mean, Father? I don’t understand,” said Timun Mas.
Right after that, Buto Ijo came into their house. “Run Timun Mas. Save your life!” said the mother. Buto ijo was angry. He knew the farmers wanted to break their promise. He chased Timun Mas away. Buto Ijo was getting closer and closer. Timun Mas then opened the bag and threw a handful of salt. It became sea. Buto Ijo had to swim to cross the sea. Later, Timun Mas threw some chilly. It became a jungle with trees. The trees had sharp thorns so they hurt Buto Ijo. However, he was still able to chase Timun Mas. Timun Mas took her third magic stuff. It was cucumber seeds. She threw them and became cucumber field. But Buto Ijo still could escape from the field. Then it was the last magic stuff she had in the bag. It was a shrimp paste or terasi. She threw it and became a big swamp. Buto Ijo was still trying to swim the swamp but he was very tired. Then he was drowning and died.
Timun Mas then immediately went home. The farmers were so happy that they finally together again.

Pengertian, Contoh, dan Rumus Passive Voice (Kalimat Pasif)

Passive Voice (Kalimat Pasif) adalah kalimat yang subject-nya dikenai suatu pekerjaan atau menderita suatu. Dengan kata lain subject kalimat tersebut menjadi sasaran kegiatan yang dinyatakan oleh kata kerja. Dalam bahasa indonesia ciri-ciri kalimat pasif adalah kata kerjanya yang berawalan dengan “di-“ dan beberapa lagi memiliki awalan “ter-“ (tergantung pada konteks kalimat).

Active Voice (Kalimat Aktif) adalah kalimat yang subject-nya berbuat sesuatau atau melakukan suatu pekerjaan. Dalam bahasa indonesia ciri-ciri kalimat aktif adalah kata kerjanya selalu berawalan “me-“ dan beberapa lagi memiliki awalan “ber-“.

Bentuk dari Passive Voice (kalimat pasif) adalah : TO BE / BE + VERB 3
 Dalam bentuk kalimat pasif, biasanya diikuti dengan frase “by”.

Contoh Passive Voice (Kalimat Passive)

ACTIVE:         Jane helps Tina. (Artinya: Jane menolong Tina)

PASSIVE:       Tina is helped by Jane. (Artinya: Tina ditolong oleh Jane)

Pada kalimat pasif, Object dari kalimat aktif (Tina) berubah menjadi Subject.

Merubah Active Voice (Kalimat Aktif) ke dalam bentuk Passive Voice (Kalimat Pasif)

Tenses	ACTIVE	PASSIVE
Simple Present	Jane helps Tina.	Tina is helped by Jane.
Present Progressive	Jane is helping Tina.	Tina is being helped by Jane.
Present Perfect	Jane has helped Tina.	Tina has been helped by Jane.
Simple Past	Jane helped Tina.	Tina was helped by Jane.
Past Progressive	Jane was helping Tina.	Tina was being helped by Jane.
Past Perfect	Jane had helped Tina.	Tina had been helped by Jane.
Simple Future	Jane will help Tina.	Tina will be helped by Jane.
To Be Going To	Jane is going to help Tina.	Tina is going to be helped by Jane.
Future Perfect	Jane will have helped Tina.	Tina will have been helped by Jane.

(Bentuk Progressive/ Continuous dari Present Perfect, Past Perfect, Future, dan Future Perfect sangat jarang digunakan dalam bentuk kalimat pasif)

Object Tak Langsung Sebagai Subject Pasif

Contoh:

ACTIVE:         Someone gave Mrs. Grim an award.

PASSIVE:       Mrs. Grim was given an award by someone.

ACTIVE:         Someone gave an award to Mrs. Grim.

PASSIVE:       An award was given to Mrs. Grim.

Direct Object (Object Langsung): Sesuatu. Indirect Object (Object tak langsung): yang menerima sesuatu. Contoh 4 kalimat di atas semuanya mempunyai makna yang sama. Mrs. Grim: sebagai object tak langsung (Indirect Object), dan an award: sebagaiobject langsung (Direct Object). Baik Object langsung  ataupun Object tak langsung bisa menjadi Subject dalam bentuk kalimat pasif. CATATAN: Ketika object langsung menjadi subject, frase “to” biasanya digunakan didepan atau sebelum object tak langsung (lihat contoh kalimat ke 4).

Semoga artikel ini bisa dipahami dan membantu untuk belajar bahasa inggris, jika bermanfaat mohon di share. Mohon maaf jika ada kesalahan dalam pengetikan. Dan untuk segala jenis pertanyaan, saran, dan kritik bisa dicantumkan pada kolom komentar. Terima kasih. 

sumber: http://letsgostudyenglish.blogspot.com/2014/07/pengertian-contoh-dan-rumus-passive.html

The Story of Lutung Kasarung

Prabu Tapa Agung was an old king. He had two daughters, Purbararang and Purbasari. Prabu Tapa Agung planned to retire as a king. He wanted Purbasari to replace him as the leader of the kingdom.

Hearing this, Purbararang was angry. "You cannot ask her to be the queen, Father. I'm older than she is. It's supposed to be me, not her!" said Purbararang. But the king still chose Purbasari to be the next queen. Purbararang then set a bad plan with her fiance, Indrajaya. Together they went to a witch and asked her to put a spell on Purbasari. Later, Purbasari had bad skin. There were black dots all over her body. "You are not as beautiful as I am. You cannot be the queen. Instead, you have to leave this palace and stay in a jungle," said Purbararang. Purbasari was very sad. Now she had to stay in the jungle. Everyday she spent her time playing with some animals there.

There was one monkey that always tried to cheer her up. It was not just an ordinary monkey, he had magical power. And he also could talk with humans. The monkey's name was Lutung Kasarung. He was actually a god. His name was Sanghyang Gurumina.

Lutung Kasarung planned to help Purbasari. He made a small lake and asked her to take a bath there. Amazingly, her bad skin was cured. Now she got her beautiful skin back. After that, she asked Lutung Kasarung to accompany her to go back to the palace.

Purbararang was very shocked. She knew she had to come up with another bad idea. She then said, "Those who have longer hair will be the queen." The king then measured his daughters' hair. Purbasari had longer hair. But Purbararang did not give up. "A queen must have a handsome husband. If my fiance is more handsome than yours, then I will be the queen," said Purbararang.

Purbasari was sad. She knew Purbararang's fiance, Indrajaya, was handsome. And she did not have a fiance yet. "Here is my fiancé, Indrajaya. Where is yours?" asked Purbararang. Lutung Kasarung came forward. Purbararang was laughing very hard. "Your fiance is a monkey, ha ha ha." Suddenly, Lutung Kasarung changed into a very a handsome man. He was even more handsome than Indrajaya.

Purbasari then became the queen. She forgave Purbararang and her fiance and let them stay in the palace.

Arabian Story

Maura, who like to be thought of as the most beautiful and powerful queen of Arabia, had many suitors. One by one she discarded them, until her list was reduced to just three sheiks. The three sheiks were all equally young and handsome. They were also rich and strong. It was very hard to decide who would be the best of them.
One evening, Maura disguised herself and went to the camp of the three sheiks. As they were about to have dinner, Maura asked them for something to eat. The first gave her some left over food. The second Sheik gave her some unappetizing camel’s tail. The third sheik, who was called Hakim, offered her some of the most tender and tasty meat. After dinner, the disguised queen left the sheik’s camp.
The following day, the queen invited the three sheiks to dinner at her palace. She ordered her servant to give each one exactly what they had given her the evening before. Hakim, who received a plate of delicious meat, refused to eat it if the other two sheiks could not share it with him.
This Sheik Hakim’s act finally convinced Queen Maura that he was the man for her. “Without question, Hakim is the most generous of you” she announced her choice to the sheiks. “So it is Hakim I will marry”.

Malin Kundang

A long time ago, in a small village near the beach in West Sumatra, a woman and her son lived. They were Malin Kundang and her mother. Her mother was a single parent because Malin Kundang's father had passed away when he was a baby. Malin Kundang had to live hard with his mother.

Malin Kundang was a healthy, dilligent, and strong boy. He usually went to sea to catch fish. After getting fish he would bring it to his mother, or sold the caught fish in the town. One day, when Malin Kundang was sailing, he saw a merchant's ship which was being raided by a small band of pirates. He helped the merchant. With his brave and power, Malin Kundang defeated the pirates. The merchant was so happy and thanked to him. In return the merchant asked Malin Kundang to sail with him. To get a better life, Malin Kundang agreed. He left his mother alone.Many years later, Malin Kundang became wealthy. He had a huge ship and was helped by many ship crews loading trading goods. Perfectly he had a beautiful wife too. When he was sailing his trading journey, his ship landed on a beach near a small village. The villagers recognized him. The news ran fast in the town; “Malin Kundang has become rich and now he is here”.An old woman ran to the beach to meet the new rich merchant. She was Malin Kundang’s mother. She wanted to hug him, released her sadness of being lonely after so long time. Unfortunately, when the mother came, Malin Kundang who was in front of his well dressed wife and his ship crews denied meeting that old lonely woman. For three times her mother begged Malin Kundang and for three times he yelled at her. At last Malin Kundang said to her "Enough, old woman! I have never had a mother like you, a dirty and ugly woman!" After that he ordered his crews to set sail. He would leave the old mother again but in that time she was full of both sadness and angriness.Finally, enraged, she cursed Malin Kundang that he would turn into a stone if he didn't apologize. Malin Kundang just laughed and really set sail.



In the quiet sea, suddenly a thunderstorm came. His huge ship was wrecked and it was too late for Malin Kundang to apologize. He was thrown by the wave out of his ship. He fell on a small island. It was really too late for him to avoid his curse. Suddenly, he turned into a stone.

The Story of Bawang Merah and Bawang Putih

Bawang  Putih lived with her step mother and her step sister, Bawang Merah. Bawang Putih's mother died when she was a baby. Her father remarried another woman and later her step sister was born. Unfortunately, not long after that her father died. Since then, Bawang Putih's life was sad. Her step mother and her step sister treated Bawang Putih badly and always asked her to do all the household chores.

One morning, Bawang Putih was washing some clothes in a river. Accidentally, her mother's clothes were washed away by the river. She was really worried so she walked along the river side to find the clothes. Finally she met an old woman. She said that she kept the clothes and would give them back to Bawang Putih if she helped the old woman do the household chores. Bawang Putih helped her happily. After everything was finished, the old woman returned the clothes. She also gave Bawang Putih a gift. The old woman had two pumpkins, one pumpkin was small and the other one was big. Bawang Putih had to choose one.

Bawang Putih was not a greedy girl. So she took the small one. After thanking the old woman, Bawang Putih then went home. When she arrived home, her step mother and Bawang Merah were angry. They had been waiting for her all day long. Bawang Putih then told about the clothes, the old woman, and the pumpkin. Her mother was really angry so she grabbed the pumpkin and smashed it to the floor. Suddenly they all were surprised. Inside the pumpkin they found jewelries. "Bawang Merah, hurry up. Go to the river and throw my clothes into the water. After that, find the old woman. Remember, you have to take the big pumpkin," the step mother asked Bawang Merah to do exactly the same as Bawang Putih's experience. Bawang Merah immediately went to the river. She threw the clothes and pretended to search them. Not long after that, she met the old woman. Again she asked Bawang Merah to do household chores. She refused and asked the old woman to give her a big pumpkin. The old woman then gave her the big one. Bawang Merah was so happy. She ran very fast. When she arrived home, her mother was impatient. She directly smashed the pumpkin to the floor. They were screaming. There were a lot of snakes inside the pumpkin! They were really scared. They were afraid the snakes would bite them. "Mom, I think God just punished us. We had done bad things to Bawang Putih. And God didn't like that. We have to apologize to Bawang Putih," said Bawang Merah.

Finally both of them realized their mistakes. They apologized and Bawang Putih forgave them. Now the family is not poor anymore. Bawang Putih decided to sell all the jewelries and used the money for their daily lives.

Cinderella Stories

Once upon a time, there was a young girl named Cinderella. She lived with her step mother and two step sisters.
The step mother and sisters were conceited and bad tempered. They treated Cinderella very badly. Her step mother made Cinderella do the hardest works in the house; such as scrubbing the floor, cleaning the pot and pan and preparing the food for the family. The two step sisters, on the other hand, did not work about the house. Their mother gave them many handsome dresses to wear.
One day, the two step sister received an invitation to the ball that the king’s son was going to give at the palace. They were excited about this and spent so much time choosing the dresses they would wear. At last, the day of the ball came, and away went the sisters to it. Cinderella could not help crying after they had left.



“Why are crying, Cinderella?” a voice asked. She looked up and saw her fairy godmother standing beside her, “because I want so much to go to the ball” said Cinderella. “Well” said the godmother,”you’ve been such a cheerful, hardworking, uncomplaining girl that I am going to see that you do go to the ball”.
Magically, the fairy godmother changed a pumpkin into a fine coach and mice into a coachman and two footmen. Her godmother tapped Cinderella’s raged dress with her wand, and it became a beautiful ball gown. Then she gave her a pair of pretty glass slippers. “Now, Cinderella”, she said; “You must leave before midnight”. Then away she drove in her beautiful coach.
Cinderella was having a wonderfully good time. She danced again and again with the king’s son. Suddenly the clock began to strike twelve, she ran toward the door as quickly as she could. In her hurry, one of her glass slipper was left behind.
A few days later, the king’ son proclaimed that he would marry the girl whose feet fitted the glass slipper. Her step sisters tried on the slipper but it was too small for them, no matter how hard they squeezed their toes into it. In the end, the king’s page let Cinderella try on the slipper. She stuck out her foot and the page slipped the slipper on. It fitted perfectly.
Finally, she was driven to the palace. The king’s son was overjoyed to see her again. They were married and live happily ever after.

Legenda – Toba Lake

Once upon a time, there was a man who was living in north Sumatra. He lived in a simple hut in a farming field. The did some gardening and fishing for his daily life.

One day, while the man was do fishing, he caught a big golden fish in his trap. It was the biggest catch which he ever had in his life. Surprisingly, this fish turned into a beautiful princess. He felt in love with her and proposed her to be his wife. She said; “Yes, but you have to promise not to tell anyone about the secret that I was once a fish, otherwise there will be a huge disaster”. The man made the deal and they got married, lived happily and had a daughter.

Few years later, this daughter would help bringing lunch to her father out in the fields. One day, his daughter was so hungry and she ate his father’s lunch. Unfortunately, he found out and got furious, and shouted; “You damned daughter of a fish”. The daughter ran home and asked her mother. The mother started crying, felt sad that her husband had broke his promise.

Then she told her daughter to run up the hills because a huge disaster was about to come. When her daughter left, she prayed. Soon there was a big earthquake followed by non-stop pouring rain. The whole area got flooded and became Toba Lake. She turned into a fish again and the man became the island of Samosir.

The Smartest Parrot

Once upon time, a man had a wonderful parrot. There was no other parrot like it. The parrot could say every word, except one word. The parrot would not say the name of the place where it was born. The name of the place was Catano.
The man felt excited having the smartest parrot but he could not understand why the parrot would not say Catano. The man tried to teach the bird to say Catano however the bird kept not saying the word.
At the first, the man was very nice to the bird but then he got very angry. “You stupid bird!” pointed the man to the parrot. “Why can’t you say the word? Say Catano! Or I will kill you” the man said angrily. Although he tried hard to teach, the parrot would not say it. Then the man got so angry and shouted to the bird over and over; “Say Catano or I’ll kill you”. The bird kept not to say the word of Catano.
One day, after he had been trying so many times to make the bird say Catano, the man really got very angry. He could not bear it. He picked the parrot and threw it into the chicken house. There were four old chickens for next dinner “You are as stupid as the chickens. Just stay with them” Said the man angrily. Then he continued to humble; “You know, I will cut the chicken for my meal. Next it will be your turn, I will eat you too, stupid parrot”. After that he left the chicken house.
The next day, the man came back to the chicken house. He opened the door and was very surprised. He could not believe what he saw at the chicken house. There were three death chickens on the floor. At the moment, the parrot was standing proudly and screaming at the last old chicken; “Say Catano or I’ll hit you”.

Buffalo, Tiger, and Farmer

One day, a tiger saw the farmer and his buffalo working in the field. The tiger was very surprised to see a big animal listening to a small animal. The tiger wanted to know more about the big animal and the small animal.

After the man went home, the tiger spoke to the buffalo; “you are so big and strong. Why do you do everything the man tells you?” The buffalo answered; “oh, the man is very intelligent”.
The tiger asked; “can you tell me how intelligent he is?”. “No, I can’t tell you”, said the buffalo; “but you can ask him”
So the next day the tiger asked to the man; “Can I see your intelligence?”. But the man answered; “it at home”. “Can you go and get it?” asked the tiger. “Yes” said the man; “but I am afraid you will kill my buffalo when I am gone. Can I tie you to a tree?”

After the man tied the tiger to the tree, he didn’t go home to get his intelligence. He took his plough and hit the tiger. Then he said; “Now you know about my intelligence even you haven’t seen it.

Story of Rabbit and Bear

Once upon a time, there lived a bear and a rabbit. The rabbit is a good shot. In contrary, the bear is always clumsy and could not use the arrow.

One day, the bear called over the rabbit and asked the rabbit to take his bow and arrows.

The rabbit was fearing to arouse the bear's anger so he could not refuse it. He went with the bear and shot enough buffalo to satisfy the hungry family. Indeed he shot and killed so many that there were lots of meats left after. However the bear did not want the rabbit to get any of the meat. The rabbit could not even taste the meat. The poor rabbit would have to go home hungry after his hard day's work.

The bear was the father of five children. Fortunately, the youngest child was very kind to the rabbit. He was very hearty eater. The mother bear always gave him an extra large piece of meat but the youngest child did not eat it. He would take it outside with him and pretended to play ball with the meat. He kicked toward the rabbit's house.When he got close to the door he would give the meat with such a great kick. The meat would fly into the rabbit's house.

In this way, the poor rabbit would get his meal.

EVERYTHING ABOUT TO BE

Apa itu to be ?To be adalah kata pelengkap dalam  suatu kalimat yang digunakan untuk menyambung dari satu kata ke kata lainnya.  To be biasanya digunakan untuk menjelaskan nominal  verbal  dan continuous verbal.Penggunaan To Be dalam Bahasa InggrisTo be juga  kerap kita temui di rumus – rumus tenses. To be itu sendiri dapat kita bedakan menjaid dua  bagian, yakni to be untuk waktu present (sekarang) dan  to be untuk past (masa lampau).

Tabel Penggunaan To Be Present
To Be	Subjek
am	I
Are	You
	They
	We
Is	He
	She
	it

Tabel Penggunaan To Be Past
To Be	Subjek
was	I
were	You
	They
	We
was	He
	She
	it

Jadi, to be kita gunakan sesuai dengan kurun  waktunya. Penggunaan to be itu sendiri lebih tampak bila kita lebih mendalami pelajaran tentang tenses.

5 Kegunaan To Be Dalam Bahasa Inggris

1. To be yang diikuti Noun / Kata Benda.
Contohnya :
·         Waktu Present
Ø   He man is a singer (Dia [pria] adalah penyanyi).
Ø  Samsul father is a policeman (bapak Samsul adalah polisi).
Ø  We are  an Indonesian football team (Kami adalah tim sepak bola Indonesia).
Ø  Izul  is a student (Izen  adalah seorang pelajar).

·         Waktu Past
Ø  Raffi is a singer two years ago  (Raffi adalah penyanyi dua tahun yang  lalu).
Ø  They were  policemans 10  years ago  (Mereka  adalah polisi 10  tahun yang  lalu).
Ø  We were  a volley ball team (Kami adalah tim bola  voli).
Ø  Zidan was a businessman (Zidan adalah seorang pebisnis).

2. To be yang diikuti Adjective / Kata Sifat
Contohnya :
·         Waktu Present
Ø  He is smart (Dia pintar).
Ø  She is beautiful girl (Dia adalah gadis  yang  cantik).
Ø  I am a good  student (Saya adalah siswa  yang  baik).
Ø  They are  happy be a winner  (Mereka  senang menjadi pemenang).

·         Waktu Past
Ø  He was stupid 3 years ago  (Dia bodoh tiga tahun yang lalu).
Ø  She was ugly 10  years ago  (Dia jelek 5  tahun yang  lalu).
Ø  The books  were  cheap 7 days  ago  (Buku itu murah 7 hari yang  lalu).
Ø  The big ball (Bola itu besar).

3. To be yang diikuti Adverb / Kata Keterangan
Contohnya :
·         Waktu Present
Ø  sister women are in a restaurant now (Adik [perempuan] berada di restoran sekarang).
Ø  Currently promptly at 8 am (Saat ini tepat jam 8 pagi).
Ø  Today is Wednesday (Hari ini adalah hari rabu).
Ø  We were there on the parade ground now (Kami ada di lapangan upacara sekarang).

·         Waktu Past
Ø  brother men are in the restaurant 4 hours ago (Adik [laki-laki] berada di restoran 4 jam yang  lalu).
Ø  The man  was here  last time (Pria tersebut disini beberapa waktu yang  lalu).
Ø  Ipin complete tasks quickly tonight (Ipin menyelesaikan tugas dengan cepat malam ini).
Ø  Yesterday was Friday (Kemaren adalah hari Jumat).

4. To  be yang diikuti Kata Kerja 1 + ing
Contohnya :
·         Waktu Present
Ø  Ivan was running in place (Ivan sedang berlari ditempat).
Ø  Izen is typing (Izen  sedang mengetik).
Ø  They are  meeting (Mereka sedang rapat).
Ø  You are  climbing  a tree (Kamu sedang memanjat sebuah pohon).

·         Waktu Past
Ø  Ivan was reading a comic yesterday (Ivan sedang membaca komik kemarin).
Ø  Upin was listening a song a hour ago (Upin sedang mendengarkan musik  satu jam yang  lalu).
Ø  Dini and Dina were preparing their presentation (Dini dan Dina sedang mempersiapkan presentasi mereka).
Ø  The cat was running last minute (Kucing itu berlari beberapa menit yang  lalu).

5. To be yang diikuti oleh Kata Kerja 3 / Past Participle
Contohnya :
·         Waktu Present
Ø  Ipul  is knocked by Anto (Ipul  ditendang oleh Anto).
Ø  Robots are  operated by computers  (Robot – robot dioperasikan oleh komputer).
Ø  The documents are  typed by Marko (Dokumen  – dokumen tersebut diketik oleh Marko).
Ø  They are  misunderstood about the information (Mereka salah mengerti tentang  infromasi tersebut).

·         Waktu Past
Ø  The ball was knocked by Zidane  (Bola tersebut ditendang oleh Zidane).
Ø  The computer was operated by Mark a hour  ago (Komputer tersebut dioperasikan oleh Mark satu jam yang  lalu).
Ø  I was listened a song  by my mother when  I was child (Saya didengarkan suatu lagu  oleh ibu  saya  ketika saya  kecil).
Ø  You were  hitted by she  (Kamu dipukul oleh dia).


 Demikianlah  pembahasan to be, semoga bermanfaat.

Pengenalan Sistem Terdistribusi

Definisi Sitem Terdistribusi

Sistem Terdistribusi adalah Sekumpulan komputer otonom yang terhubung kesuatu jaringan, dimana bagi pengguna sistem terlihat sebagai satu komputer.

Dengan menjalankan sistem terdistribusi, komputer dapat melakukan : Koordinasi Aktifitas dan berbagi sumber daya: hardware, software dan data.

Contoh Sistem Terdistribusi

1. Sistem Telepon : ISDN, PSTN
2. Manajemen Jaringan: Adminstrasi sesumber jaringan
3. Network File System (NFS) : Arsitektur untuk mengakses
4. sistemfile melalui jaringan
5. WWW : Arsitektur client/server yang diterapkan diatas Infrastruktur internet, Shared Resource (melaluiURL)
6. dll

KeuntunganSistemTerdistribusi

• Performance
• Distribution
• Reliability (Fault tolerance)
• Incremental Growth
• Sharing Data/Resources

Kelemahan pada sistem terdistribusi adalah

1. Kesulitandalammembangunperangkatlunak
2. Bahasa pemrogramman, sistem operasi dll.
3. MasalahJaringan: merancang& mengimplementasikan sistem.
4. Masalah Keamanan: berbagidata/sumberdaya
5. Berkaitan dengan keamanan data dll.

KarakteristikSistemTerdistribusi

Hal yang diperhatikan dalam membangun sistem terdistribusi:

a. Transparency (Kejelasan)

b. Communication (Komunikasi)

c. Performance & Scalability (KinerjadanRuangLingkup)

d. Heterogenity(Keanekaragaman)

e. Opennes(Keterbukaan)

f. Reliability dan Fault Tolerancy(Kehandalan danToleransi Kegagalan)

g. Security (Kemanan)

Model dalamSistemTerdistribusi

a. Model Arsitektur(Architectural Models)

b. Model Interaksi(Interaction Models)

c. Model Kegagalan(Failure Models)

a. Architectural Models

Cara kerja antar komponen sistem dan bagaimana komponen tsb berada pada sistem terdistribusi:

- Client -Server Model

- Proxy Server

- Peer processes ( peer to peer )

Client-Server Model

Model client-server biasanya berbasiskan protokol request/reply.

Contoh: Implementasi RPC (Remote Procedure Calling) danRMI (Remote Method Invocation) :

• client mengirimkan request berupa pesan ke server untuk mengakses suatu service.
• server menerima pesan tersebut dan mengeksekusi request client dan mereply hasil ke client

Proxy Server

• menyediakan hasil copy (replikasi) dari resource yang diatur oleh server lain
• dipakai untuk menyimpan hasil copy web resources.
• Ketika client melakukan request kes erver, proxy server diperiksa apakah yang diminta oleh client terdapat pada proxy server.
• Diletakkan pada setiap client atau dapat dipakai bersama oleh beberapa client. Tujuannya adalah meningkatkan performance dan availibity dengan mencegah frekwensi akses ke server.

Peer Process

• Semua proses(object) mempunyai peranyang sama.
• Proses berinteraksi tanpa adanya perbedaan antara client dan server.
• Polakomunikasi yang digunakan berdasarkan aplikasi yang digunakan.
• •Merupakan model yang paling general dan fleksible.

b. Interaction  Models 

dibagi menjadi dua bagian:

• Synchronous distributed system
• Asynchronous distributed system Synchronous Distributed System
• Batas atas dan batas bawah waktu pengeksekusian dapat diset.
• Pesan yang dikirim, diterima dalam waktu yang sudah ditentukan
• Fluktuasi ukuran antara waktu lokal berada dalam suatu batasan.

Beberapa hal yang penting untuk diperhatikan synchronous distributed sistem:

• terdapat satu waktu global
• dapat memprediksi perilaku(waktu)
• dimungkinkan dan aman untuk menggunakan mekanisme timeout dalam mendekteksi error atau kegagalan dalam proses atau komunikasi

Asynchronous Distributed System

Banyak sistem terdistribusi yang  menggunakan model interaksi ini(termasuk Internet)

• Tidak ada batasan dalam waktu pengkeksekusian.
• Tidak ada batasan dalam delay transmission (penundaan pengiriman)
• Tidak ada batasan terhadap fluktuasi waktu local. Asynchronous system secara parktek lebih banyak digunakan.

c. Failure Models

Kegagalan apa saja yang dapat terjadi dan bagaimana efek yang ditimbulkan?

• Omission Faluires
• Arbitary Failures
• Timing Failures

Model Kegagalan (Failure Models) dibutuhkandalam membangun suatu sistem dengan prediksi terhadap kagagalan yang mungkin terjadi.

OmmisionFailures :

Ketika prosesor dan kanal komunikasi mengalami kegagalan untuk melakukan halyang seharusnya dilakukan.

Dikatakan tidak mempunyai ommision failures apabila:

•Terjadi keterlambatan (delayed) tetapi akhirnya tetap tereksekusi.

•Sebuah aksi dieksekusi walaupun terdapat kesalahan pada hasil.

Dengan synchronous system, ommision failures dapatdideteksi dengan timeouts.

ArbitaryFailures

• kegagalan yang paling buruk dalam sistem.
• Tahapan proses atau komunikasi diabaikan atau yang tidak diharapkan terjadi dieksekusi -> hasil yang diharapkan tidak terjadi atau megeluarkan hasil yang salah.

Timing Failures

• Dapat terjadi pada synchronous system, dimana batas waktu diatur untuk eksekusi proses, komunikasi dan fluktuasi waktu.
• Timing Failures terjadi apabila waktu yang telah ditentukan terlampaui.

Sumber : http://loveensimple.blogspot.com/2014/01/catatan-pengenalan-sistem-terdistribusi.html

http://sonsums.blogspot.com/2015/04/pengenalan-sistem-terdistribusi.html