Computer Systems Flashcards
What is the range of numbers of 8 bit
-128 to 127
What is the range of numbers of 12 bits
-2048 to 2047
What is the range of numbers of 16 bits
-32768 to 32767
How many characters can ASCII represent
256
How many bits does a character have in ASCII
8
How many characters can Unicode represent
65336
How many bits does a character have in Unicode
16
What is an advantage and disadvantage of using ASCII
Uses up less space but can only represent english alphabet
What is an advantage and disadvantage of using Unicode
Can represent more symbols and letters but uses up more space
How are things stored in bitmap graphics
As a grid of pixels, they are resolution dependant meaning if resized it will become blurry and the quality will go down
What is bitdepth
The amount of bits in a pixel which determines the colour
How are things stored in Vector graphics
Stores the object attributes of shapes, resolution independant meaning if resized the quality will the stay the same
What are the advantages and disadvantages of using Bitmap
More realistic images and can be edited in fine detail
Take up more storage space and are resolution dependant meaning if they are resized the image will become pixelated
What are the advantages and disadvantages of using Vector
They are resolution independant meaning they will not become pixelated when resized
You can change the order of them so positioning objects behind each other
They are not suitable for storing realistic photographic images
What are the 3 types of buses
address bus
data bus
control bus
What does the address bus do
Carries address info from processor to main memory
Uni-directional
What does the data bus do
Carries data to and from the processor
Bi-directional
What is the fetch execute cycle
The processor sets up the address bus with the required address.
The processor activates the read line on the control bus
An instruction is fetched from the memory location using the data bus and stored in the memory data register
The instruction in the instruction register is then translated and executed
How could you increase system performance
Increase clock speed
Increase amount of cores
Increase data bus width
Increase cache
How can intelligent systems reduce environment impact in heating systems
Use sensors to detect if people in room and turn on when motion detected
Learn from previous days, time the heating should turn on
use smartphone apps to turn on/off
How can intelligent systems reduce environment impact in traffic systems
satnav can be used to guide people away from congestion to stop constant stopping and starting which burns fuel
How can intelligent systems reduce environment impact in car management systems
Intelligent sys control engine, turn off when not moving and back on when you stop braking
Sensors optimise engine performance by controlling air to fuel ratio
What are the symptoms, effects and motives of a DOS attack
Can’t access site, the system is very slow
Actual users can’t access to their accounts or info they need on the site
Personal - attacker may have been fired by company
Political - may be state sponsored
Financial - attacker may want ransom money
What is encryption
Encryption encodes data making it scrambled and unintelligible
Data is encrypted with Public Key and Decrypted with Private Key
