Computational Thinking

Question 1

Define abstraction

Answer 1

Abstraction is the process of hiding unnecessary details while showing details that are more important in context

Question 2

As a computational method, what is the purpose of abstraction in problem solving

Answer 2

As a computational thinking method abstraction allows to solve problems by focusing on what’s important and ignoring what isn’t

Question 3

Explain two benefits of abstraction before writing program code

Answer 3

Two from:
Reduced development time as factors that can detract from the program can be ignored

Program more likely to solve the problem as unnecessary aspects will not detract from the main purpose of the program

Reduces complexity of programming code therefore can run on lower spec computers

Question 4

What is the difference between a real life model and a model that has be abstracted

Answer 4

The real life model will have every detail, while the abstracted model may have removed certain details to make it easier to understand

Question 5

How can we use the computational method ‘thinking ahead’ to outline the inputs and outputs for a system while designing it

Answer 5

The typical approach for this method is to think about what the system should output, i.e. what is the end goal

From here you can back track and create the inputs that should eventually lead to the previously outlined desired outputs

Question 6

Describe the purpose of preconditions when thinking ahead

Answer 6

Preconditions may act as limitations and can effect the solution produced.

When thinking about how to solve a problem or design a system, preconditions should be thought about ahead of time to determine whether an idea is feasible

Question 7

Describe the purpose of caching in a computer system as a form of thinking ahead

Answer 7

Caching is where a computer system places data in cache memory so it can be retrieved quickly. Smart algorithms can be used to prefetch data that is predicted to be need ahead of time

Question 8

Give 1 benefit and 1 drawback of caching

Answer 8

Benefit:
improved speed and efficiency when accessing data

Drawback:
The predictive nature of caching is hard to implement and it can often lead to the wrong data being fetched, leading to it having to be removed(flushed). Maintaining the correct sequence of data in such circumstances is problematic

Question 9

Give two benefits of using reusable code

Answer 9

two from:

Shortens development time
Save system resources
Lowers development costs
Reduces redundant code

Question 10

Give two benefits of using reusable code

Answer 10

two from:

Shortens development time
Save system resources
Lowers development costs
Reduces redundant code

Question 11

How does writing code in a modular way allow for the benefits of reusable code

Answer 11

Creating subroutines such as procedures, functions and methods is an example of reusable coding.

They are blocks of code than can be used multiple times simply by calling them, saving time, money and resources

Question 12

How does the use of libraries allow for the benefits of reusable code

Answer 12

All the pre-written and pre-tested code in the library is available for the programmer to use as long as they import it. This saves them from having to write their own, potentially flawed, versions saving time, money and resources

Question 13

Explain how think procedurally allows for a large complex task to become more manageable

Answer 13

Think procedurally is identifying the individual components in a bigger problem.

In this way, a large complex problem can be broken down in smaller, more manageable chunks

Question 14

Name two types of diagrams which can be used to break down a problem

Answer 14

Decomposition diagrams
Top-down modular design/ structure diagrams

Question 15

Why is it useful to consider decision points when designing a system/ program

Answer 15

Think logically by considering where decisions will have to be made allows us to consider and evaluate our options, which will likely result in a better outcome

Question 16

What programming type can be used to make logical decisions and set logical conditions that effect the outcome of the decision

Answer 16

Selection

Question 17

Describe the process of thinking concurrently

Answer 17

Thinking concurrently is a skill which involves which parts of a program can be developed to take place, or be processed, at the same time

And on the flip side which parts of the program are dependent on each other

Question 18

Define concurrency

Answer 18

Executing multiple tasks at the same time, but not necessarily simultaneously

Question 19

What is the difference between concurrency and parallelism

Answer 19

Concurrency is about dealing with lots of things at once, while parallelism is about doing lots of things at once

dealing vs doing

Question 20

Give benefits of concurrent processing

Answer 20

The number of tasks completed in a given time is increased

The time wasted by the processor waiting on the user or another process is reduced

Question 21

Name and explain two drawbacks of concurrent processing

Answer 21

two from:

Safety:
Possibility of corrupting the consistent state of the program

Liveness:
Tasks can suspend and wait on each other indefinitely, known as deadlock

Resource consumption:
Multiple threads can consume resources in regards to scheduling, which may result in slower performance compared to ordinary sequential means