Section 10 - Computational thinking

Question 1

2.1.1 Thinking abstractly

Explain what is ment by representational abstraction

Answer 1

● Removing excessive details to represent a problem using only the key features

● Must analyse what is relevant to a scenario and simplify a problem based on this

Question 2

2.1.1 Thinking abstractly

Explain what is ment by data abstraction.

Answer 2

● Details about how data is being stored are hidden.

● Programmers can use data structures without knowing how they are implemented.

Question 3

2.1.1 Thinking abstractly

Explain what abstraction by generalisation is.

Answer 3

● Grouping together similarities within a problem to identify what kind of problem

● Allows problems to be categorised as being of a particular type

● A common solution can be used to solve these problems

Question 4

2.1.1 Thinking abstractly

Explain what procedural abstraction is.

Answer 4

● Allows programmers to utilise functions without knowing how they are implemented

● Used in decomposition and manipulating data structures

● Models what a subroutine does without considering how, as once a subroutine has been written, it can be reused as a black-box

Question 5

2.1.1 Thinking abstractly

What is the need for abstraction?
( generally )

Answer 5

● Abstraction allows non-experts to use of a range of systems or models by hiding information that is too complex or irrelevant to the system’s purpose

● Enables for efficient software design as programmers can focus on core elements
rather than unnecessary details
- Reduces the time spent on a project
- Prevents a program from getting unnecessarily large.

Question 6

2.1.1 Thinking abstractly

Describe how abstraction is used within programming languages

Answer 6

• Low-level languages directly interacts with computers but are difficult to write
• High-level languages abstract the machine code that is executed when a program is run by providing easy-to-use syntax similar to natural language
• Makes developing programs easier
• High-level languages are easier to learn and use than assembly language or machine code
• Makes coding accessible to non-specialists

Question 7

2.1.1 Thinking abstractly

Explain how the TCP/IP model is a form of abstraction.

Answer 7

• The TCP/IP model is an abstraction for how networks function, separated into four layers: application, transport, internet and link
• Each layer deals with a different part of the communication process
• Each layer does not need to know how other layers function

Question 8

2.1.1 Thinking abstractly

Explain the difference between abstraction and reality

Answer 8

● Abstraction is a simplified representation of reality

● Entities are represented as computational structures eg. tables and databases

● Real-world values can be stored as variables and constants

● Objects in object-oriented programming are an abstraction for real-world entities

Question 9

2.1.1 Thinking abstractly

What are some questions to consider when devising an abstract model.

Answer 9

• What is the problem that needs to be solved by the model?
• How will the model be used?
• Who will the model be used by?
• Which parts of the problem are relevant based on the target audience and purpose of the model?

Question 10

2.1.1 Thinking ahead

Outline the benefits and drawbacks of caching

Answer 10

Benefits:
- Gives fast access to pages that have been recently looked up
- Saves having to download pages again, using up bandwith unnecessarily

Drawbacks:
- The cache may store an outdated version of data, leading to inconsistencies if the original source
- If the required data is not in the cache, the system must search for it in slower memory (e.g., RAM or disk), which can lead to slower performance than not using a cache at all.