Information Technology: Fundamentals, Networks and Digital Tools
Information Technology
In the PSEB Senior Secondary NSQF IT/ITeS trade, the Information Technology domain tests NSQF-aligned QP/NOS competencies: hardware and software, operating-system and file-management tasks, networking and internet services, cybersecurity, digital documentation and spreadsheets, plus basic database and programming logic. Questions mix definitions with applied calculations and troubleshooting, so know both the term and the correct unit or process.
Core rules and concepts
- Data units: 1 byte = 8 bits. Storage may use binary prefixes (1 KiB = 1,024 bytes) or decimal prefixes (1 kB = 1,000 bytes); bandwidth is usually bits per second.
- Software: system software manages hardware and provides a platform; application software performs user tasks. Open formats aid interoperability; proprietary formats may need specific software.
- Operating-system roles: process, memory, file and device management; user interface; access control.
- Networking: an IP address identifies a host; a subnet mask separates network and host portions; DNS resolves names to IP addresses; DHCP leases addresses. A switch forwards within a LAN; a router forwards between networks.
- Security: protect confidentiality, integrity and availability; use strong unique passwords, MFA, patched software, verified backups and phishing awareness. Do not collect or expose personal data without need.
Worked example
An uncompressed 1,024 × 768 image uses 24-bit colour. Pixels = 1,024 × 768 = 786,432. Bits = 786,432 × 24 = 18,874,368. Bytes = 18,874,368 ÷ 8 = 2,359,296. In MiB = 2,359,296 ÷ 1,048,576 = 2.25 MiB; in decimal MB ≈ 2.36 MB. Reasoning: colour depth is bits per pixel, so 24-bit means 3 bytes per pixel, not 24 bytes. Compression would reduce the file, but this calculation is for uncompressed data.
Traps that cost marks
- Mixing bits and bytes, or binary and decimal prefixes.
- Confusing RAM (volatile) with ROM (non-volatile).
- Treating HTTP as secure; HTTPS adds TLS but does not prove a site is trustworthy.
- Confusing a router with a switch, or an IP address with a MAC address.
- Using Save when Save As is required to keep the original file unchanged.