Total marks: 60 · Duration: 1 hour 30 minutes
Instructions to candidates
• Answer all questions. • Use black ink or black ball-point pen. • The number of marks is given in brackets [ ] at the end of each question or part question. • You may use a calculator. • The total number of marks for this paper is 60. • All the information you need is contained within the questions.
Paper
Section A — Structured Questions (44 marks)
1. Data representation
(a) Convert the 8-bit binary number 0011 0101 into denary (base 10). Show your working. [2]
(b) Convert the denary number 206 into an 8-bit binary number. Show your working. [4]
(c) Explain why computers use binary to represent all data, and state what is meant by a bit and a byte. [4]
2. Computer hardware and the CPU
(a) State what is meant by the CPU and give its main function. [2]
(b) Explain the role of two of the following in the CPU: the control unit, the arithmetic logic unit (ALU), and registers. [4]
(c) Explain the difference between RAM and ROM, and give one example of what each is used to store. [4]
3. Networks and the internet
(a) State what is meant by a protocol in networking. [2]
(b) Explain the difference between a LAN and a WAN. [4]
(c) Data sent over the internet is often encrypted. Explain what encryption is and why it is important, and describe one other way of keeping data secure over a network. [6]
4. Algorithms and programming
(a) State what is meant by an algorithm. [2]
(b) A program uses the pseudocode below.
total = 0
FOR i = 1 TO 5
INPUT number
total = total + number
NEXT i
average = total / 5
OUTPUT average
Explain what this algorithm does, and identify the type of loop used. [4]
(c) Explain the difference between a compiler and an interpreter, and give one advantage of each. [6]
Section B — Extended Response (16 marks)
5. A school is considering allowing students to store all their work on cloud storage instead of on the school's own local server.
Discuss the advantages and disadvantages of using cloud storage rather than a local server, and advise the school on what it should consider before deciding. Reach a supported conclusion. [16]