SLR5 Flashcards
What are the 2 types of software
- Application software
- System software
Give 2 examples of an application software
- Word processor
- Web browser
What are the 2 types of system software
- Utility software
- OS (Operating Systems)
Give 2 examples of utility software
- Anit-virus
- Malware
Give 2 examples of OS
- MacOs
- Windows
When did computing become commercialised
1970s
When did it become illegal to steal code
1983
Name 2 benefits of open source code for users
- The software is free
- There is a wide community for modification
Name 2 drawbacks of open source code for users
- Poorly supported by designer
- Not well tested
Name 1 benefit of open source code for creators
Gets your software out into the community
Name 1 drawback of open source code for creators
Little to no financial gain
Name 1 benefit of closed source code for users
Well-supported and professional
Name 1 drawback of closed source code for users
Expensive
Name 1 benefit of closed source code for creators
Receive an income
Name 2 drawback of closed source code for creators
- Community can be demanding
- Privacy issues
What are the 5 types of Utility software
- File repair
- Back-ups
- Data compression
- Defragmentation
- Anti-malware
What is the purpose of file repair
To repair a damaged or corrupted file
What is the purpose of back-ups
To have multiple saves of each file so that it can be replaced if lost
How should back-ups be ran
- Back-ups can be incremental where everything new or changed will be saved
- Back-ups can be full meaning every backup everything is saved (this takes up much more space
- Back-ups can be automatically scheduled
What is the purpose of data compression
To reduce the file size of the data
How do you read a compressed file
It must be uncompressed or extracted
What is the purpose of defragmentation
To reduce the movement of the read-write head across of the surface of the disk
What is the purpose of anti-malware
To get rid of malware (such as viruses, trojans, worms, spyware)
How is anti-malware acquired
Can be purchased directly from the companies designing it or can be bought with your computer from a company such as Apple
What is Binary also called
Machine code
What is source code also called
Human code
What is Translation
The process of converting source code into machine code
How does a compiler run code
By compacting all the code into one and then running it
How does an interpreter run code
By running each line individually one after the other
What is the first stage of compiler known as
Lexical Analysis
What is the second stage of the compiler known as
Syntax Analysis
What are the third stage of the compiler known as
Code generation
What does Lexical analysis do
- Removes comments and white space
- The remaining code turned into a series of tokens
- A symbol table is created to keep track of variables and subroutines
What does Syntax analysis do
- An abstract syntax tree is built from tokens produced in the previous stage
- Error generated if any tokens break the rules of the language
What is the fourth stage of the compiler known as
Optimisation
What does code generation do
- The abstract code tree is turned into object code
- Object code is machine code produced before the final step is run
What does optimisation do
Tweaks the code so it will run as quickly as possible
What is a library
A ready-compiled and tested program that can be run when needed and are typically grouped in software libraries
Name 4 benefits of libraries
- Quick
- Easy
- Pre-tested
- Pre-compiled
Name 3 drawbacks of libraries
- Functionality is almost impossible to tweak
- Black Boxed
- You have to trust the developer
What does the Linker do
Puts the appropriate machine addresses in all the external call and return instructions
What are the two types of linking
- Static linking
- Dynamic linking
What does Static linking do
Includes all required code from the libraries in the finished machine code
What does Dymanic linking do
- Stores compiled versions of the required libraries on the host computer
- Links the OS to the required code from the library as the program is running
- Cuts down the size of the machine code
What is the loader
A part of the OS that loads the executable program file into memory ready to be run along with the required libraries
