Basics of Information Technology
Basics of Information Technology is the foundation chapter: it tests whether you can explain how data becomes information, name the hardware blocks of a computer, and convert between the number systems digital devices use. Expect definition questions plus one small conversion.
Core rules and concepts
- Data are raw facts; information is processed data that supports decisions.
- The CPU has three functional parts: the Arithmetic Logic Unit (ALU) for calculations and comparisons, the Control Unit (CU) for fetching and sequencing instructions, and registers for temporary storage.
- Primary memory is accessed directly by the CPU: RAM is volatile and holds running programs; ROM is non-volatile and stores firmware such as the BIOS.
- Secondary storage (HDD, SSD, pen drive) is non-volatile but slower and is not executed from directly.
- 1 byte = 8 bits; 1 KB = 1024 bytes; 1 MB = 1024 KB.
- Number systems: binary base 2, octal base 8, decimal base 10, hexadecimal base 16.
Worked example
Convert decimal 45 to binary by repeated division by 2, reading remainders bottom-up: 45 ÷ 2 = 22 remainder 1 22 ÷ 2 = 11 remainder 0 11 ÷ 2 = 5 remainder 1 5 ÷ 2 = 2 remainder 1 2 ÷ 2 = 1 remainder 0 1 ÷ 2 = 0 remainder 1 Reading upward gives 101101₂. Check: 32 + 8 + 4 + 1 = 45.
Traps that cost marks
- Saying RAM is non-volatile, or that ROM is routinely rewritten.
- Using 1000 instead of 1024 for KB when describing binary memory size.
- Reading the remainders top-down in a decimal-to-binary conversion.
- Confusing the ALU (does arithmetic) with the CU (coordinates and decodes instructions).
- Writing hexadecimal values above 9 as 10–15 instead of A–F.