1.2.2 Applications generation Flashcards
What is a utility?
Utility software includes all systems and programs on a computer system that maintain its functionality.
Name 5 types of utility software?
File repair
Backup
Data compression
Defragmentation
Anti-malware
What does defragmentation software do?
Defragmentation reorganises files on a hard disk. putting fragments of files and free space back together
Define open source software?
Open source code can be used by anyone without a license and is distributed with the source code.
Define closed source software?
Closed source code requires the user to hold an appropriate license to use it. Users cannot access the source code as the company owns the copyright license.
Give 2 advantages of open source software?
Can be modified and improved by anyone
Technical support from online community
Give a disadvantage of open source software?
Lower security as may not be developed in a controlled environment
Give 2 advantages of closed software?
Thorough, regular and well-tested updates
High levels of security as developed professionally.
Give a disadvantage of closed software?
Users cannot modify and improve software themselves
What is a translator?
A translator is a program that converts high-level source code into low-level object code
What are the 3 types of translators?
Compiler
Interpreter
Assembler
What is a compiler?
A compilers translate high-level code into machine code all at once, after carrying out a number of checks and reporting back any errors.
What is a interpreter?
Interpreters translate and execute code line-by-line. They stop and produce an error if a line contains an error.
What is a assembler?
Assembly code is considered to be a low-level language as it is the ‘next level up’ from machine code.
Name 2 advantages of using a compiler?
Compiled code tends to run faster than interpreted code because it has been translated into machine code that can be directly executed by the computer’s processor
Compilers allow programmers to write code in a high-level programming language that can be easily translated into machine code for a variety of different platforms.
Name 2 disadvantages of using a compiler?
Compilation can take a significant amount of time.
If changes need to be made, the whole program must be recompiled.
Name 2 advantages of using a interpreter?
Executes line by line. Hence, debugging is easy.
No intermediate code hence uses the memory efficiently
Name a disadvantages of using a interpreter?
Execution time is more.
What are the four stages of compilation in order?
- Lexical analysis
- Syntax analysis
- Code generation
- Code optimisation
What 2 steps happen in lexical analysis?
- Whitespace and comments are removed from the code
- The remaining code is analysed for keywords and names of variables and constants, these are replaced with tokens and information about the token associated with each keyword or identifier is stored in the symbol table.
What 2 steps happen in syntax analysis?
Tokens are analysed against the grammar and rules of the programming language. Any tokens that break the rules of the programming language are flagged up as syntax errors and added to a list of errors.
An abstract syntax tree is produced, which is a representation of the source code in the form of a tree.
What step happens in Code generation?
What is a linker?
This is a piece of software that is responsible for linking external modules and libraries included within the code.
What are the 2 different types of linkers?
Static
Dynamic
Describe a static linker?
Modules and libraries are added directly into the main file.
Describe a dynamic linker?
Addresses of modules and libraries are included in the file where they are referenced. When the program is run, the loader retrieves the program at the specified address so it can be executed.
What is a loader?
Loaders are programs provided by the operating system. When a file is executed, the loader retrieves the library or subroutine from the given memory location.
