Higher Computer Systems quiz

Front

Convert the decimal number -19 into an 8-bit two’s complement representation.

Back

19 in binary:

0001 0011,

invert bits: 1110 1100,

add 1: 1110 1101

Front

What is the largest positive integer that can be represented using 8-bit two’s complement?

Back

127 (Range: -128 to 127)

Front

Convert the following binary number 10110101 into decimal (unsigned).

Back

181 (1×128 + 0×64 + 1×32 + 1×16 + 0×8 + 1×4 + 0×2 + 1×1)

Front

Explain the effect of increasing the number of bits allocated to the mantissa in floating-point representation.

Back

More bits improve precision, reducing rounding errors. More detailed calculations become possible without increasing range.

Front

Describe the steps of the fetch-execute cycle.

Back

Step 1: Processor sets the address bus with memory location.

Step 2: Control unit sends read signal, instruction fetched to instruction register.

Front

State two factors that affect processor performance and their impact.

Back

Clock speed: Higher speed = more instructions per second. Cache size: Larger cache reduces RAM access, speeding up performance.

Front

Identify two types of malware and their effects.

Back

Virus: Attaches to programmes and spreads.

Ransomware: Encrypts files and demands payment.

Front

Explain how public key encryption secures online transactions.

Back

Sender encrypts data with recipient’s public key; only recipient can decrypt with private key, preventing unauthorised access.

Front

Describe a situation where the Computer Misuse Act 1990 could be breached.

Back

Example: A student alters grades in a school system = unauthorised modification of data.

Can you think of another example?

Front

Describe the difference between RAM and cache memory.

Back

RAM: Stores active programmes and data, but slower than cache.

Cache: Stores frequently accessed instructions, improving CPU speed.