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BCS Preliminary Test study materials
BCS Preliminary Test study resources

BCS Preliminary Test: Computer and Information Technology

BCS Preliminary Test · Work through your exam, one topic at a time.

All guide sections

Computer and Information Technology

Core concepts

Hardware and software fundamentals, number systems (binary, decimal, octal, hexadecimal), computer generations, networking (LAN, WAN, IP addressing), internet services, and cybersecurity basics. Also know common file extensions, input/output devices, and basic database concepts.

Traps to expect

  • Bit vs. byte: 1 byte = 8 bits; storage units step by 1024, not 1000, for binary prefixes.
  • Number system conversion: binary 1011 = decimal 11 = hexadecimal B. Practice the 8-4-2-1 weighting.
  • RAM vs. ROM: RAM is volatile and read/write; ROM is non-volatile and read-only.
  • LAN vs. WAN: LAN is small and local; WAN spans large areas (the internet is the largest WAN).
  • HTTP vs. HTTPS: HTTPS adds encryption via TLS; the "S" does not mean "secure server" as a separate protocol.

Rule of thumb

For binary-to-decimal, assign place values 8, 4, 2, 1 (for four bits) and sum where a 1 appears. For decimal-to-binary, divide repeatedly by 2 and read remainders bottom-up.

Worked example

Convert decimal 13 to binary: 13 ÷ 2 = 6 remainder 1; 6 ÷ 2 = 3 remainder 0; 3 ÷ 2 = 1 remainder 1; 1 ÷ 2 = 0 remainder 1. Reading bottom-up gives 1101. Check with place values: 8 + 4 + 0 + 1 = 13. The trap is reading remainders top-down, which yields 1011 (= 11).