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NIELIT BCC study materials
NIELIT BCC study resources

NIELIT BCC: Computer Fundamentals: Hardware, Software and Data Representation

NIELIT BCC · Work through your exam, one topic at a time.

All guide sections

Computer Fundamentals: Hardware, Software and Data Representation

The machine model

The BCC syllabus tests the stored-program computer: input → processing → output, with storage. Know the block diagram and the role of each unit.

  • CPU: Arithmetic Logic Unit (ALU) performs arithmetic and logic; Control Unit (CU) fetches, decodes and executes instructions; registers hold immediate operands. Clock speed is measured in GHz.
  • Primary memory: RAM is volatile working memory; ROM is non-volatile and holds startup firmware; cache is fast, small and close to the CPU.
  • Secondary storage: hard disk, SSD, optical disc and pen drive retain data without power.
  • Units: 1 byte = 8 bits; 1 KB = 1024 bytes; 1 MB = 1024 KB; 1 GB = 1024 MB; 1 TB = 1024 GB.
  • Software: system software (operating system, utilities, drivers) versus application software (word processor, browser). Firmware sits between hardware and software.
  • Number systems: binary (base 2), octal (8), decimal (10) and hexadecimal (16).

Worked example

Convert binary 11011010 to decimal and hexadecimal. Write place values from the left: 128, 64, 32, 16, 8, 4, 2, 1. The 1s fall on 128, 64, 16, 8 and 2. Sum = 128 + 64 + 16 + 8 + 2 = 218. Group the same bits as 1101 1010: 1101 = D (13), 1010 = A (10), so the hexadecimal value is DA. Checking: 13 × 16 + 10 = 218.

Traps that cost marks

Mixing bit and byte; calling RAM non-volatile; treating ROM as always unchangeable; confusing storage capacity with memory; saying a GUI is an operating system; forgetting that hexadecimal uses A–F for 10–15.