Describe a compiler translator
Translates source code all at once into machine code, it won’t identify errors, but it means the translator program is no longer needed. Is very quick as well.
Describe an interpreter translator
Translates source code one line at a time and reports errors immediately, is good for testing programs during development. However it is quite slow.
What does the data bus do?
Carries data or instructions to and from the processor after getting instructional data from the memory or opposite way round. Its bi-directional
What are the two types of translators?
Interpreter and compiler
How do Firewalls work and what do they do?
Firewalls monitor incoming and outgoing data packets, they have rules to block certain packets based on sender or receiver address, port or contents. A firewall protects a network against unauthorised access.
What does the ALU (Arithmetic and Logic Unit) in the processor do?
Comparisons, mathematical and logical calculations.
How could you reduce energy usage?
Monitor: - lower the brightness
- standby mode
Power down the computer when not in use
What is encryption?
“the process of scrambling data with a key so it can’t be read again without it”
Encryption scrambles stored files and data that is being transmitted over a network.
What do bitmap graphics do?
store images as a 2D array
What 2 types of encryption are there?
Asymmetric encryption and symmetric encryption
What is Asymmetric encryption?
Has 2 keys and is used to communicate over a distance, relies on a public and private key.
What is Symmetric encryption?
Has 1 key and is used when it is easy to share the key securely.
Describe computers, what are they?
Binary devices that take in an input, process it and output it as new information.
What are the 2 different memory’s?
RAM and ROM
What is RAM?
Random Access Memory,
RAM is:
- a block of storage locations connected to the processor by the data bus and address bus
- used to store data, programs and the operating system
- volatile meaning its contents are cleared when it has no power i.e. the computer is switched off
What is ROM?
Read Only Memory,
read only
What does the address bus do?
Carries a memory address from the processor to the memory controller, allowing the processor to access a particular location in memory. It’s uni-directional.
What is the mantissa and exponent in this?:
3 x 10^8
Mantissa: 3
Exponent: 8
What is binary/machine code?
Easy to represent, does not get affected by degradation.
What do vector graphics do?
Store images as a series of instructions, describing their objects and attributes.
What are some vector attributes?
Co-ordinates
line colours
fill colours
size
What is bit depth?
Bit depth defines the number of bits used per pixel, therefore the number of colours that can be represented.
What are bit-mapped graphics?
There are 3 examples, such as:
- JPEG
-GIF
-PNG
Stored in a grid of pixels, each pixel gets its own binary number that corresponds to its colour.
