Applications generation

Question 1

What is application software

Answer 1

Software that allows a user to perform a task or produce something

Question 2

Examples of application software

Answer 2

• Word processor
• Spreadsheet packages
• Presentation software
• Desktop publishing software
• Image editors
• Web browsers
• Database management systems

Question 3

What is a utility software

Answer 3

Small programs designed to help with the maintenance of a system.

Question 4

Examples of utility software

Answer 4

• Anti-malware
• Disk defragmentation
• Backup

Question 5

What is source code

Answer 5

The program code written by the programmer, usually in high-level language

Question 6

What is closed source software

Answer 6

Software only distributed as machine code

Question 7

What is open source software

Answer 7

Software where the source code is made freely available and grants users the right to examine, modify and share it

Question 8

ADV of open source

Answer 8

• No enforced deadlines as the code is written by volunteers
• Users are free to amend the source code of open source software and adapts it to their purposes
• Lower costs of development

Question 9

ADV of closed source

Answer 9

• Usually polished to attract customers
• Technical support is formally avaliable
• Arguably more secure as the source code is not available so weaknesses are not so apparent

Question 10

What is machine code

Answer 10

Instructions and data stored in binary, directly readable by the CPU

Question 11

What is assembly code

Answer 11

A low-level language that uses single words or mnemonics to represent instructions

Question 12

What is a assembler

Answer 12

A program that converts assembly code into machine code

Question 13

What are low-level languages

Answer 13

These are languages closely tied to the architecture of the CPU. They use the CPU’s instruction set

Question 14

What are high-level languages

Answer 14

These are designed to be easily read by humans. They tend to use a combination of English keywords and mathematical notation.

Question 15

What is a compiler

Answer 15

A program that converts the entire high-level source code into an executable machine code file that is then executed

Question 16

What is a interpreter

Answer 16

A program that reads and executes high-level source code line-by-line

Question 17

What are the stages of compilation

Answer 17

• Lexical analysis
• Syntax analysis
• Code generation
• Code optimisation

Question 18

What happens during lexical analysis

Answer 18

Identifies the parts that make up the program:
- comments and whitespace are removed
- the remaining code is turned into a series of tokens each representing a small discrete part of the program
- a symbol table is created to keep track of the variables and subroutines

Question 19

What happens during code generation

Answer 19

The abstract code tree is converted to object code

Question 19

What happens during syntax analysis

Answer 19

Checks the structure of a language:
- an abstract syntax tree is built from the tokens produced
- if any tokens break the rules of the language, syntax errors are created

Question 20

What happens during code optimisation

Answer 20

Tweaks the code so it will run as efficiently as possible

Question 21

What is object code

Answer 21

When code is compiled but yet to be run through a linker

Question 22

What are libraries

Answer 22

Already written code to perform common complex tasks and packaged as libraries

Question 23

ADV of libraries

Answer 23

• Save time
• Cover complex areas that may require significant expertise that would be ime-consuming to learn
• A library coded in one language can be used in programs written in another language

Question 24

What is a linker

Answer 24

Used to combine compiled code with that from a library into a single executable file

Question 25

What is a loader

Answer 25

Parts of the OS and is responsible for loading a program into memory