AP Computer Science Principles Flashcards: Parallel and Distributed Computing
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 31 cards to help you master important concepts.
What is sequential computing?
Sequential computing is a computational model in which operations are performed in order one at a time.
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What is sequential computing?
Sequential computing is a computational model in which operations are performed in order one at a time.
How does parallel computing achieve its speed advantage?
It achieves a speed advantage by breaking a program into smaller operations and performing some of them simultaneously, rather than one at a time.
Which computational model performs operations strictly one at a time?
Sequential computing is the model where operations are performed in order one at a time.
How is the total time for a sequential solution calculated?
A sequential solution takes as long as the sum of all of its steps.
What are the two main portions of any parallel computing solution?
Parallel computing consists of a parallel portion and a sequential portion.
Identify two resource needs that might require a distributed computing solution.
A problem might require a distributed solution if a single computer lacks the necessary processing time or storage needs.
How does distributed computing affect the time it takes to solve very large problems?
Distributed computing allows much larger problems to be solved quicker than they could be solved using a single computer.
Which computational model breaks a program into smaller, simultaneously performed operations?
Parallel computing breaks a program into smaller sequential operations, with some performed simultaneously.
A sequential solution involves 5 steps, each taking 4 seconds. What is its total runtime?
The total runtime is the sum of all steps, so 5 steps multiplied by 4 seconds equals 20 seconds.
What is the fundamental method for determining which of two solutions is more efficient?
To determine which solution is more efficient, you compare the time it takes for each to perform the same task.
What is a primary benefit of distributed computing over using a single computer?
Distributed computing allows much larger problems to be solved more quickly and can handle tasks that exceed a single computer's processing or storage capacity.
What happens to efficiency gains if you keep adding more parallel portions to a solution?
At some point, adding more parallel portions will no longer meaningfully increase the efficiency of the solution because of the sequential portion's time limit.
A sequential task takes 60 minutes. A parallel version takes 15 minutes. What is the speedup?
The speedup is the sequential time (60) divided by the parallel time (15), which is 4.
How is the total time for a parallel computing solution calculated?
A parallel solution's time is the sum of its sequential tasks plus the time of its longest parallel task.
What are the three computational models discussed for problem-solving?
The three models are sequential, parallel, and distributed computing.
How is the efficiency of different problem solutions compared?
The efficiency of solutions can be compared by measuring the time it takes them to perform the same task.
Why is there a limit to the speedup achievable through parallel computing?
The speedup is limited because every parallel solution still contains a sequential portion, which does not get faster as more parallel tasks are added.
Compare the core concepts of parallel and distributed computing.
Parallel computing breaks one program into simultaneous tasks on one machine, while distributed computing uses multiple devices to run a program.
Which computational model, sequential or parallel, scales more effectively?
Solutions that use parallel computing can scale more effectively than solutions that use sequential computing.
A problem can be solved sequentially in 20 hours. Using parallel computing, it takes 4 hours. Calculate the speedup.
The speedup is the sequential time (20 hours) divided by the parallel time (4 hours), resulting in a speedup of 5.
What is parallel computing?
Parallel computing is a model where a program is broken into smaller sequential operations, some of which are performed simultaneously.
What is a primary benefit of parallel computing over sequential computing?
A primary benefit is that solutions using parallel computing can scale more effectively than those using sequential computing.
What is distributed computing?
Distributed computing is a computational model in which multiple devices are used to run a program.
If a sequential program has three steps taking 10, 5, and 15 seconds, what is the total execution time?
The total time is the sum of all steps (10 + 5 + 15), which is 30 seconds.
What is the ultimate limiting factor for the efficiency of a parallel computing solution?
The efficiency of a parallel solution is still limited by its sequential portion.
What is the "speedup" of a parallel solution?
Speedup is a measurement calculated by dividing the time it took to complete a task sequentially by the time it took to complete it in parallel.
A program has a 5-second sequential part and two parallel tasks taking 8 and 12 seconds. What is the total time?
The total time is the sequential part (5s) plus the longest parallel task (12s), which equals 17 seconds.
Which computational model uses multiple devices to run a program?
Distributed computing is the model that uses multiple devices to run a program.
What is a major benefit of distributed computing for solving massive problems?
Distributed computing allows problems to be solved that could not be solved on a single computer due to processing time or storage needs.
What is a key challenge of parallel computing related to its structure?
A key challenge is that the solution's efficiency is ultimately limited by the sequential portion, which cannot be parallelized.
A parallel solution has a 3-minute sequential portion. It then runs three parallel tasks that take 5, 9, and 4 minutes. How long does the entire solution take?
The total time is the sequential portion (3 min) plus the longest parallel task (9 min), for a total of 12 minutes.