UPMSP High School Computer cheat sheet

Input → Process → Output → Storage (IPOS) cycle: CPU processes, RAM holds active data, secondary storage is non-volatile.

CPU components: ALU performs arithmetic/logic; Control Unit fetches-decodes-executes; registers (PC, IR, MAR, MBR) are fastest storage.

Memory hierarchy by speed and cost: registers > cache > RAM > SSD/HDD > optical > tape; capacity generally increases downward.

Primary memory is volatile (RAM) or ROM (non-volatile firmware); secondary memory (HDD, SSD, DVD) retains data without power.

Ports: USB (universal serial bus, hot-swappable), HDMI (audio+video), VGA (analog video), Ethernet RJ-45 (wired LAN).

Units: 1 byte = 8 bits; 1 KB = 1024 B; 1 MB = 1024 KB; 1 GB = 1024 MB; 1 TB = 1024 GB.

Hardware vs software: hardware is physical; software is instructions - system software (OS, utilities) vs application software (editors, browsers).

Input devices: keyboard, mouse, scanner, microphone, webcam; output devices: monitor, printer, speaker, plotter.

Decimal base 10 uses digits 0–9; binary base 2 uses 0–1; octal base 8 uses 0–7; hexadecimal base 16 uses 0–9 and A–F.

Binary to decimal: multiply each bit by 2^position (rightmost position 0) and sum; e.g., 1011₂ = 8+0+2+1 = 11₁₀.

Decimal to binary: repeatedly divide by 2 and read remainders bottom-up; e.g., 13 → 1101₂.

Group 4 bits = 1 hex digit; group 3 bits = 1 octal digit; conversion between binary, octal, and hex is direct.

1's complement: flip all bits; 2's complement: flip all bits then add 1 - used to represent negative integers in computers.

ASCII uses 7 bits (128 codes); extended ASCII uses 8 bits (256 codes); Unicode supports multilingual scripts (UTF-8, UTF-16).

Logic gates: AND (1 only if both inputs 1), OR (1 if any input 1), NOT (inverts), NAND/NOR (inverted AND/OR), XOR (1 if inputs differ).

Data units: bit (0/1), nibble (4 bits), byte (8 bits), word (CPU-dependent, often 16/32/64 bits).

OS functions: process management, memory management, file system management, device management, and user interface (GUI/CLI).

Types: single-user vs multi-user; batch, time-sharing, real-time, distributed, and mobile OS (Android, iOS).

Common OS: Windows (GUI, NTFS), Linux (open source, ext4), macOS (Unix-based, APFS), Android (Linux kernel).

File path: absolute path starts at root (C:\ or /); relative path starts from current directory; extensions (.txt, .docx, .jpg) indicate format.

File operations: create, open, read, write, rename, copy, move, delete; folder (directory) organizes files hierarchically.

Keyboard shortcuts: Ctrl+C copy, Ctrl+X cut, Ctrl+V paste, Ctrl+Z undo, Ctrl+S save, Ctrl+A select all, Alt+Tab switch apps.

Disk management: formatting prepares storage; defragmentation reorganizes HDD; partitioning divides a disk into logical drives.

Word processor features: text formatting (bold, italic, underline), alignment, bullets/numbering, tables, headers/footers, mail merge.

Spreadsheet cell reference: column letter + row number (e.g., B5); range written as A1:C10.

Relative reference (A1) changes when copied; absolute reference ($A$1) stays fixed; mixed uses $A1 or A$1.

Formula begins with =; operators + - * / ^; functions: =SUM(A1:A10), =AVERAGE(), =COUNT(), =MAX(), =MIN(), =IF(condition, true, false).

Charts: column/bar for comparison, line for trend over time, pie for parts of a whole; chart data source must be selected.

Sorting arranges rows by a column; filtering hides rows that do not match criteria without deleting data.

Print setup: page orientation (portrait/landscape), margins, print area, scaling to fit page.

Slide layout defines placeholders (title, content, image); Slide Master controls consistent fonts, colors, and background.

Transitions apply between slides; animations apply to objects within a slide; use sparingly for clarity.

Multimedia elements: text, image (raster/vector), audio, video, animation; file types: .jpg/.png (image), .mp3/.wav (audio), .mp4/.avi (video).

Resolution: pixels per inch (ppi); higher resolution = sharper image but larger file; vector graphics scale without pixelation.

Compression: lossy (JPEG, MP3) reduces size by discarding data; lossless (PNG, ZIP) preserves exact data.

Presentation best practice: one idea per slide, readable font size (≥24 pt for body), high contrast, minimal text, consistent theme.

Slide show shortcuts: F5 start from beginning, Shift+F5 start from current slide, Esc end, B black screen.

Network types by scale: PAN (personal), LAN (local), MAN (metropolitan), WAN (wide, e.g., Internet).

Topologies: star (central hub/switch), bus (single backbone), ring (closed loop), mesh (redundant links); star is most common in LANs.

IP address identifies a device; IPv4 is 32-bit dotted decimal (e.g., 192.168.1.1); IPv6 is 128-bit hexadecimal.

DNS translates domain names to IP addresses; URL structure: protocol://domain/path?query#fragment.

HTTP/HTTPS: HTTPS encrypts traffic using TLS; port 80 (HTTP), 443 (HTTPS), 25 (SMTP), 110 (POP3), 143 (IMAP).

Web browsers (Chrome, Firefox, Edge) render HTML/CSS/JS; search engines index pages and rank by relevance.

Email fields: To, Cc (carbon copy), Bcc (blind carbon copy), Subject, Attachment; protocols: SMTP sends, POP3/IMAP receive.

Algorithm: finite sequence of unambiguous steps to solve a problem; flowchart symbols: oval (start/end), parallelogram (input/output), rectangle (process), diamond (decision).

Three control structures: sequence, selection (if/else, switch), iteration (for, while, do-while).

Variable stores a value in memory; constant cannot change; data types: integer, float, char, string, boolean.

Operators: arithmetic (+ - * / %), relational (== != < > <= >=), logical (AND, OR, NOT); precedence: parentheses > arithmetic > relational > logical.

Loops: for (known count), while (condition checked before body), do-while (body runs at least once).

Functions/procedures take parameters and may return a value; modular design improves reuse and debugging.

Debugging: syntax errors violate grammar; runtime errors occur during execution; logical errors produce wrong output without crashing.

Strong password: length ≥12, mix of upper/lower case, digits, symbols; avoid dictionary words and personal data; use unique passwords per site.

Phishing: fraudulent messages that trick users into revealing credentials; verify sender, hover over links, never share OTPs.

Malware types: virus (attaches to files), worm (self-replicates over network), trojan (disguised as legitimate), ransomware (encrypts data for payment), spyware (collects data).

Firewall filters network traffic; antivirus scans for known threats; keep OS and apps updated; back up data regularly.

Digital footprint: online activity leaves a persistent record; personal information should be shared cautiously.

Cyber ethics: respect copyright, avoid plagiarism, do not access others' accounts, report cyberbullying, follow acceptable-use policies.

Indian legal context: Information Technology Act, 2000 addresses cybercrime; cybercrime can be reported at cybercrime.gov.in.

Lab file structure: aim, apparatus/software, procedure, observations, result, conclusion - record neatly with date.

Spreadsheet practical: enter data, apply formulas, create a chart, format cells, sort/filter, print with headers.

Word practical: create a document with headings, table, image, page numbers, and mail merge or table of contents.

Presentation practical: 5–8 slides with title slide, content slides, consistent theme, one chart or image, and speaker notes.

Project documentation: title page, certificate, acknowledgement, index, chapters, bibliography; cite sources properly.

Viva preparation: be able to explain each step, formula, and output; know file extensions and shortcuts used.

Assessment often includes practical file (neatness, completeness), project (originality, relevance), and viva (understanding).