Computer Science
What the Computer Science section tests
The paper covers basic computer literacy: hardware and software, input/output devices, memory, operating systems, word processing and spreadsheets, networks, the internet, email, and security. It is practical, so know what each component does and the common file types.
Core rules
- CPU executes instructions; RAM is volatile working memory; ROM is non-volatile and stores firmware.
- Input devices send data in (keyboard, scanner); output devices send data out (monitor, printer).
- An operating system manages hardware, files, and processes; examples include Windows, Linux, and macOS.
- A spreadsheet formula begins with =; =SUM(A1:A5) adds the range A1 through A5.
- Binary is base 2; each digit is a bit, and 8 bits make a byte.
- HTTPS encrypts traffic between browser and server; HTTP does not.
Worked example
Convert binary 1011 to decimal. Reasoning: write place values from the right: 2⁰=1, 2¹=2, 2²=4, 2³=8. The bits are 1, 1, 0, 1 from right to left, so the value is 1×1 + 1×2 + 0×4 + 1×8 = 1 + 2 + 0 + 8 = 11. The decimal equivalent is 11.
Traps that cost marks
- Calling RAM non-volatile; it loses contents when power is off.
- Confusing a byte with a bit.
- Using a word processor when the task needs a spreadsheet calculation.
- Treating HTTP and HTTPS as equally secure.
- Clicking links in unsolicited email; phishing is a social-engineering attack, not a hardware fault.