Applications generation

Question 1

Define applications software (AS)

Answer 1

A software that allows a user to perform a task or produce something

Question 2

What is a word processor (AS)

Answer 2

Used for writing letters, reports and other documents

Question 3

what are spreadsheet packages (AS)

Answer 3

These allow a user to model complex situations, and are often used for financial calculations

Question 4

what is presentation software (AS)

Answer 4

Used to make onscreen slide shows to accompany presentations

Question 5

what is desktop publishing software (AS)

Answer 5

Used for documents where the layout is
important, such as newsletters

Question 6

what are image editors (AS)

Answer 6

Used to alter and amend images such as photographs

Question 7

What are Web browsers

Answer 7

Allow a user to browse the World Wide Web

Question 8

Give some examples of specialist applications and define

Answer 8

• Computer-aided design packages allow engineers to build designs
• Management information systems allow data to be stored and processed
• video games provide entertainment

Question 9

define utility software

Answer 9

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

Question 10

name three examples of utility software

Answer 10

• Anti-malware
• Disk defragmentation
• Backup

Question 11

What is the purpose of anti-malware

Answer 11

Used to detect and remove malware on the system

Question 12

How does disk defragmentation software help the computer

Answer 12

rearranges where data is held on the hard disk drive so that files load quicker

Question 13

How does backup software operate

Answer 13

Used to make copies of data to an alternative device or location, this can be set to occur automatically

Question 14

Define Source code

Answer 14

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

Question 15

what is closed-source software

Answer 15

• Software that is only distributed as executable machine code
  most users do not need the program’s machine code

Question 16

what is machine code

Answer 16

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

Question 17

What is open-source software (OSS)

Answer 17

• Software where the source code is made publically available
• Users can modify it to their needs
  Grants anyone permission to amend, recompile and distribute

Question 18

Advantages of open-source software

Answer 18

• Free
• Users can change the source code of OSS and adapt it to their needs
• Anyone can help find security holes in the program

Question 19

Advantages of closed-source software

Answer 19

• Tends to be more polished than OSS (developed by companies with lots of resources)
• Can be developed by huge teams of volunteers who do not need to consider the aims of the project
• People cannot exploit security holes before they are fixed

Question 20

A03 open-source VS. closed-source

Answer 20

Open source
- Trust (Client can see exactly what the company is doing)
- Other people can steal
- Different types of open-source software

Question 21

How are instructions represented

Answer 21

Machine code - They are binary and are made up of the opcode (the instruction itself) and operand (the data it acts on)

Computers only understand machine code

Question 22

What is assembly code

Answer 22

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

The opcode is represented in denary or hexadecimal

Question 23

How is assembly code converted to machine code

Answer 23

An assembler is used to convert each line of assembly of code into machine code

Question 24

what is a low-level language

Answer 24

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

• The lowest-level language is
  machine code, which is
  directly readable by the
  CPU.

Question 25

What is a high-level language

Answer 25

These are designed for humans to read easily. They tend to use a combination of English words and mathematical notation

Question 26

How can a computer run code written in high-level languages

Answer 26

The program must be converted into machine code using a compiler or an interpreter

Question 27

What is a compiler

Answer 27

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

Question 28

What is an interpreter

Answer 28

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

Question 29

Advantages/Disadvantages of a compiler

Answer 29

dis - Can take a while to perform adv - Once the executable file is built it can be run immediately

Question 30

Advantages/Disadvantages of an interpreter

Answer 30

adv - Can start running the program straight away - Useful during the coding and debugging process as the programmer doesn't have to wait for the entire program to compile dis - Run more slowly than it would if it were complied as the interpreter has to translate each line as it is run

Question 31

What are the steps of compilation

Answer 31

- Lexical analysis - Syntax analysis - Code generation - Code optimisation

Question 32

Describe the first stage of compilation (lexical analysis)

Answer 32

Identifies the parts that make up the program - Comments and whitespace are removed from the program # - The remaining code is turned into a series of tokens (each representing a part of the program) - A symbol table is created to keep track of variables and subroutines

Question 33

Describe the second stage of compilation (syntax analysis)

Answer 33

The syntax is the structure of a language - A syntax tree is built from the tokens produced during lexical analysis - If any tokens break the rules of the language, syntax errors are generated

Question 34

Describe the third stage of compilation (code generation)

Answer 34

The abstract code tree is converted to object code

Question 35

What is object code

Answer 35

When code is complied but yet to be run through a linker.

Question 36

Describe the fourth stage of compilation (code optimisation)

Answer 36

This tweaks the code so it is run as efficiently as possible. This might mean optimising for : - Speed of execution - Using as little memory as possible

Question 37

What is a library

Answer 37

Code that has already been written and usually complied. Other programmers can reuse this code

Question 38

Advantages of libraries

Answer 38

- They can save time(no need to rewrite code) - They can cover complex areas (prewrite code that would be too time-consuming to learn how to do yourself) - A library coded in one language can be used in other languages

Question 39

What is a linker used for

Answer 39

It is used to combine compiled code with that from a library into a single executable file

Question 40

What is the loader used for

Answer 40

A loader is part of the operating system and is responsible for loading a program into memory