Information Technology - MATSEC SEC
What the domain covers
SEC Information Technology tests how computer systems represent, store, process and communicate data, your practical competence in standard applications, and your awareness of security, legal and ethical issues. Expect definitions, scenario questions and calculations, not just recall. Answers should use correct technical vocabulary.
Core rules and concepts
- Data representation: convert binary, denary and hexadecimal; 8 bits = 1 byte, 1024 bytes = 1 KiB, 1024 KiB = 1 MiB. Bitmap size = width × height × colour depth; sound size = sample rate × bit depth × duration × channels.
- Systems: the CPU repeats fetch–decode–execute; RAM is volatile working memory, ROM is non-volatile; cache reduces average access time; virtual memory uses secondary storage when RAM fills. An operating system manages files, memory, processes and peripherals; utilities maintain the system.
- Networks: LAN versus WAN; IP addresses are logical, MAC addresses are hardware; HTTP/HTTPS, SMTP and FTP are protocols; bandwidth is capacity, latency is delay. HTML structures web pages, CSS controls presentation; DNS resolves domain names to IP addresses.
- Applications: relative spreadsheet references change when copied; absolute references ($A$1) do not. Database primary keys ensure entity integrity; foreign keys create relationships. Validation checks input; verification confirms data entry.
- Security and society: malware, phishing, encryption, backups, access rights, copyright and data-protection principles such as lawful purpose, accuracy and retention limits.
Worked example
Find the uncompressed size of a 1024 × 768 bitmap at 24-bit colour. Pixels = 786,432. Bits = 786,432 × 24 = 18,874,368. Bytes = ÷8 = 2,359,296. KiB = ÷1024 = 2304. MiB = ÷1024 = 2.25. Answer: 2.25 MiB (2304 KiB). Show units at each step; a bare number loses method marks.
Traps
- Mixing decimal MB (10^6 bytes) with binary MiB (2^20 bytes); use binary unless told otherwise.
- Forgetting 24-bit colour = 3 bytes per pixel.
- Assuming absolute references change when a formula is copied.
- Calling a foreign key unique; it may repeat or be null.
- Confusing lossy compression (JPEG, MP3) with lossless (PNG, ZIP), and RAM with ROM.
- Writing HTML tags to control colour or layout when CSS is expected, or leaving a calculation unlabelled.