Computer Systems

Question 1

ASCII number of characters calculation

Answer 1

2 ^ 7 = 128

Question 2

Extended ASCII number of characters calculation

Answer 2

2 ^ 8 = 256

Question 3

Unicode number of characters calculation

Answer 3

2 ^ 16 65536

Question 4

two’s complement range formula

Answer 4

-2ⁿ⁻¹ to 2ⁿ⁻¹ -1, where n is the number of bits

Question 5

computer structure

Answer 5

Arithmetic Logic Unit (ALU)
Control Unit (CU)
Internal Clock
Registers
Data Bus
Address Bus
Control Bus
Main Memory (RAM)
Cache

Question 6

bitmap graphics

Answer 6

edited at pixel level
more storage than vector graphics
good for photos

Question 7

vector graphics

Answer 7

edited based on shapes and values
shape info is stored instead of individual pixels (stores data like length and colour)

Question 8

system performane

Answer 8

number of processors
width of data bus
cache size
clock speed

Question 9

environmental impact

Answer 9

heating systems
traffic control
car management systems

Question 10

computer misuse act

Answer 10

unauthorised access
modifying material without permission
deliberate introduction of a virus
Using Unauthorised Access or modification of computer systems to facilitate further criminal offences

Question 11

tracking cookies

Answer 11

can pose a security risk if hackers get access

Question 12

DoS/DDoS

Answer 12

DoS is when a single computer causes an attack
DDoS is when multiple computers/bots cause an attack

causes reduced system function
can cause loss of revenue and can be costly to fix
can be motivated by financial, personal, or political reasons
types: resource starvation, bandwidth consumption, DNS (denial of service) attack

Question 13

Encryption

Answer 13

symmetric key, asymmetric/public key
symmetric: keys are the same, risk of someone getting the key and decrypting private info.
asymmetric: public key and private key, both keys are linked via large prime numbers, can only be decrypted with both keys, private key is kept secure

Question 14

Fetch execute cycle

Answer 14

1. Processor sets up address bus with the relevant address
2. The control unit read line is activated
3. An instruction is fetched from the memory location using the data bus and is stored in the instruction register
4. The instruction is then interpreted by the decoder and carried out

address, read line, instruction, interpreted and carried out