Distributed computing concept in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main advantage of distributed computing?

Imagine you have a big puzzle to solve. You can either solve it alone or ask friends to help by working on different parts at the same time. What is the main advantage of using distributed computing in this example?

A It makes the puzzle easier by reducing the number of pieces.

B It uses only one computer to avoid confusion.

C It allows solving the puzzle faster by sharing the work among many computers.

D It guarantees the puzzle will be solved without any mistakes.

💡 Hint

Think about how sharing work helps finish tasks quicker.

Distributed computing splits a big task into smaller parts and runs them on multiple computers simultaneously, speeding up the overall process.

❓ trace

intermediate

Trace the message flow in a distributed system

Look at the flowchart below showing how a request moves through a distributed system with three computers (A, B, and C). Which computer processes the request last?

A Computer B

B Computer C

C Computer A

D User's device

💡 Hint

Follow the arrows in the flowchart from start to end.

The request starts at the user's device, goes to computer A, then B, and finally C, which processes it last.

❓ Comparison

advanced

Compare centralized and distributed computing

Which statement correctly compares centralized computing and distributed computing?

A Centralized computing cannot handle any failures; distributed computing never fails.

B Centralized computing is faster because it uses many computers; distributed computing uses only one computer.

C Distributed computing always requires less network communication than centralized computing.

D Centralized computing uses one main computer; distributed computing uses multiple computers working together.

💡 Hint

Think about how many computers are involved in each approach.

Centralized computing relies on a single main computer, while distributed computing spreads tasks across multiple computers.

❓ identification

advanced

Identify the challenge in distributed computing

Which of the following is a common challenge faced in distributed computing systems?

A Ensuring all computers have the same time and data (synchronization).

B Making sure only one computer is used at a time.

C Avoiding the use of networks to connect computers.

D Reducing the number of computers to one.

💡 Hint

Think about what happens when many computers work together and need to agree.

Synchronization is a key challenge because computers must coordinate their actions and data to work correctly together.

🚀 Application

expert

Determine the output of a distributed task split

A task is split into three parts and sent to three computers. Each computer returns the number of items it processed: A returns 5, B returns 7, and C returns 8. What is the total number of items processed?

A 20

B 19

C 21

D 18

💡 Hint

Add the numbers returned by each computer.

Adding 5 + 7 + 8 equals 20, which is the total number of items processed.

Practice

1. What is the main idea behind distributed computing?

easy

A. Splitting a big task into smaller parts and running them on many computers

B. Using one very fast computer to do all the work

C. Storing all data on a single computer

D. Running programs without any network connection

Solution

1. Step 1: Understand the concept of distributed computing

   Distributed computing means breaking a large problem into smaller tasks that multiple computers can work on at the same time.

2. Step 2: Compare options with the concept

   Splitting a big task into smaller parts and running them on many computers matches this idea exactly. Options A, C, and D do not involve splitting tasks or using multiple computers.

3. Final Answer:

   Splitting a big task into smaller parts and running them on many computers -> Option A

4. Quick Check:

   Distributed computing = splitting tasks across computers [OK]

Hint: Distributed means many computers share the work [OK]

Common Mistakes:

• Thinking distributed means one computer does all work
• Confusing distributed computing with offline computing
• Assuming data is stored on only one machine

2. Which of the following is the correct way computers in a distributed system communicate?

easy

A. By printing results on paper

B. By sharing the same keyboard and mouse

C. By using the same hard drive directly

D. By sending messages over a network

Solution

1. Step 1: Identify communication methods in distributed systems

   Computers in distributed systems communicate by exchanging messages through a network connection.

2. Step 2: Evaluate each option

   By sending messages over a network correctly describes message passing over a network. Options B, C, and D are not practical or correct communication methods for distributed computing.

3. Final Answer:

   By sending messages over a network -> Option D

4. Quick Check:

   Communication in distributed computing = message passing [OK]

Hint: Distributed computers talk by sending messages [OK]

Common Mistakes:

• Thinking they share hardware directly
• Assuming physical devices like keyboard are shared
• Confusing communication with printing output

3. Consider a distributed system where 4 computers each process 25% of a task simultaneously. If one computer fails, what is the likely effect?

medium

A. The whole task stops immediately

B. The task may slow down or need reprocessing

C. The failed computer finishes the task alone

D. The task completes faster

Solution

1. Step 1: Understand fault tolerance in distributed systems

   If one computer fails, the system may slow down because the failed part needs to be redone or handled by others.

2. Step 2: Analyze each option

   The task may slow down or need reprocessing correctly states the task may slow or need reprocessing. The whole task stops immediately is too absolute; many systems handle failures. The task completes faster is incorrect because failure does not speed up work. The failed computer finishes the task alone is impossible since the failed computer cannot work.

3. Final Answer:

   The task may slow down or need reprocessing -> Option B

4. Quick Check:

   Failure in distributed system = slowdown or rework [OK]

Hint: Failure causes delay or retry, not speedup [OK]

Common Mistakes:

• Assuming failure stops all work immediately
• Thinking failure makes task faster
• Believing failed computers still work

4. A distributed system is designed to split a task into 3 parts, but the code only sends messages to 2 computers. What is the main problem?

medium

A. One part of the task is not assigned or processed

B. All parts are processed twice

C. The system runs faster than expected

D. The network connection is too fast

Solution

1. Step 1: Identify the issue with message sending

   If messages are sent to only 2 computers but the task has 3 parts, one part is left unassigned.

2. Step 2: Evaluate the impact

   One part of the task is not assigned or processed correctly states the missing part is not processed. Options A, B, and D do not relate to the problem described.

3. Final Answer:

   One part of the task is not assigned or processed -> Option A

4. Quick Check:

   Missing messages = missing task part [OK]

Hint: Each task part needs a message to a computer [OK]

Common Mistakes:

• Assuming unassigned parts are processed anyway
• Thinking parts get duplicated automatically
• Ignoring message-to-task part matching

5. You want to speed up processing a large dataset by using distributed computing. Which approach best ensures reliability if some computers might fail?

hard

A. Run the same task on all computers without splitting data

B. Assign the entire dataset to one computer only

C. Split data into parts and assign each part to multiple computers for backup

D. Use only one computer and ignore failures

Solution

1. Step 1: Understand reliability in distributed computing

   To handle failures, tasks or data parts should be duplicated on multiple computers as backup.

2. Step 2: Analyze options for reliability

   Split data into parts and assign each part to multiple computers for backup uses redundancy to ensure reliability. Options B and D rely on one computer, risking failure. Run the same task on all computers without splitting data wastes resources and does not split data efficiently.

3. Final Answer:

   Split data into parts and assign each part to multiple computers for backup -> Option C

4. Quick Check:

   Reliability = redundancy in distributed tasks [OK]

Hint: Backup tasks on multiple computers for safety [OK]

Common Mistakes:

• Ignoring backup and redundancy
• Using single computer for big tasks
• Duplicating entire dataset on all computers inefficiently