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Systems Essential KU Qs

Terms in this set (18)

How are real numbers represented in computer memory? (3)
Answer: As floating point representation (1), storing the mantissa (1) and exponent (1) of the number
How is text represented in computer memory? (1)
ASCII - each character is 8 bits and is given a unique binary code.
What is a control character? Give an example (2)
Answer:
•A non-printable character that has an effect (1)
•Space, ESC, enter (1)
Give an example of a printable character (1)
Answer: Any letter, number, punctuation or symbol: A, E, N, K etc.
How many bits are required to store one character? (1)
8 bits
How do we calculate the number of bits required to store a String? (1)
Answer: Count the number of characters, and multiply by 8 (the number of bits required to store one character)
How many characters are required to store "Welcome home!"? (2)
Answer: 13*8 = 104 bits
1 mark for working showing the correct number of bits, 1 mark for correct answer
Write the python code for calculating how many bits are required to store "Welcome home!" (2)
Answer:
length = len("Welcome home!") (1)
bits = length * 8 (1)
How are bitmapped graphics stored in computer memory? (2)
Answer: Bitmapped graphics are composed of a 2D grid of pixels (1). The colour of each pixel is stored as a binary number (1)
How are vector graphics stored in computer memory? (1)
Answer: Vector graphics store objects with a list of attributes (1)
Name the four vector object shapes (4)
Answer:
•Ellipse (1)
•Line (1)
•Rectangle (1)
•Polygon (1)
What 3 attributes can objects have? (3)
Answer:
•Line colour (1)
•Fill colour (1)
•X and Y co-ordinates (1 - must state X and Y for mark)
State one advantage and one disadvantage of creating a bitmap graphic over a vector graphic (2)
Answer:
Advantage (1) - can be manipulated at pixel level to represent more photo realistic images
Disadvantage (1) - large file size, so requires more storage; image becomes jagged when scaled
Give one advantage and one disadvantage of creating a vector graphic over a bitmap graphic (2)
Answer:
Advantage (1) - does not lose quality when scaled; requires less storage space; objects can be easily moved or manipulated; resolution independent

Disadvantage (1) - cannot be edited at pixel level, so cannot show photo-realistic scenes as bitmap can; usually requires specific applications to open
State two security precautions, and describe how each of these restrict unauthorised access to data and computer systems/networks (2)
Answer:
•Encryption - encodes data into an unreadable form, making it unreadable by unauthorised/restricted users (1)
•Firewalls - restricts unauthorised access by filtering incoming traffic (packets), considering IP addresses, port numbers, and protocols (1)
Name and describe the three parts of the processor (3)
Answer:
•Control Unit (CU) - controls the order of execution and timing of instructions (1)

•Arithmetic and Logic Unit - performs the calculations for the processor and carries out logical decisions (1)
•Registers - temporarily stores data (1)
What is a bus? (1)
Answer: A collection of wires that carries data
Name and explain the three types of buses (3)
Answer:
•Data bus - carries data between the CPU and memory (1)
•Address bus - carries the address of the memory location (1)
•Control bus - carries control signals from the processor to other components (1)
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