Karnataka KSEAB SSLC NSQF Information Technology cheat sheet

Computer = input unit + CPU (ALU, control unit, registers) + memory (primary: RAM/ROM; secondary: HDD/SSD) + output unit; the stored-program concept means instructions and data share memory.

Data units: 1 nibble = 4 bits, 1 byte = 8 bits, 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB, 1 TB = 1024 GB.

Number systems: binary base 2, octal base 8, decimal base 10, hexadecimal base 16; hexadecimal digits 0-9 and A-F; 1 hex digit = 4 bits.

Decimal to binary: divide repeatedly by 2 and read remainders bottom-up; binary to decimal: multiply each bit by 2^position (positions start at 0 from the right) and sum.

RAM is volatile and holds running programs; ROM is non-volatile and holds firmware/BIOS; cache is fastest and smallest; secondary storage is non-volatile and largest.

1s complement = invert all bits; 2s complement = 1s complement + 1, used to represent negative numbers and to perform subtraction by addition.

ASCII uses 7 bits (128 codes); Unicode supports multiple scripts; 1 ASCII character = 1 byte, and ISCII/Unicode encodings handle Indian languages.

Hardware vs software: system software (OS, utilities, device drivers) runs the machine; application software (word processor, spreadsheet) serves the user; firmware is software stored in ROM.

OS functions: process management, memory management, file management, device management, security, and providing a user interface (CLI or GUI).

Booting: POST checks hardware, then the bootstrap loader in ROM loads the OS kernel from secondary storage into RAM.

Multitasking = several processes share the CPU by time-slicing; multiprocessing = two or more CPUs; multiuser = several users share one system.

File name = name + extension; the extension after the dot indicates type: .txt text, .docx document, .xlsx spreadsheet, .pptx presentation, .jpg image, .mp3 audio, .mp4 video, .exe executable.

A folder (directory) holds files and subfolders; a path such as C:\Users\Student\notes.txt gives drive, folders, and file name; the root is the top of the hierarchy.

File operations: create, open, save, rename, copy, move, delete, and restore; deleted files go to the Recycle Bin and can be restored until it is emptied.

Absolute path starts from the root or drive; relative path starts from the current folder; wildcards * (any characters) and ? (one character) match file names.

Compression reduces file size (ZIP); extracting restores contents; file attributes include read-only, hidden, and archive.

Word processor uses: typing and editing text, formatting, spell and grammar check, find and replace, tables, images, headers/footers, page numbering, mail merge, and printing.

Alignment options: left, centre, right, justify; line spacing sets vertical gaps; paragraph spacing sets space before/after a paragraph.

Font properties: typeface, size in points (1 point = 1/72 inch), bold, italic, underline, colour, and case change.

Page setup controls margins (top, bottom, left, right), orientation (portrait height > width; landscape width > height), and paper size such as A4.

Mail merge needs a main document (letter with merge fields) and a data source (table of names/addresses); it produces one personalised copy per record.

Find (Ctrl+F) locates text; Find and Replace (Ctrl+H) changes all occurrences; Undo (Ctrl+Z) reverses the last action; Redo (Ctrl+Y) reapplies it.

A table is a grid of rows and columns; a cell is the intersection; cells can be merged or split and borders/shading applied.

Track changes records edits for review; comments attach notes without altering text; a table of contents is generated from heading styles.

A workbook contains worksheets; a worksheet is a grid of columns (A, B, C...) and rows (1, 2, 3...); a cell reference such as B5 or $A$1 identifies one cell; a range is written A1:C10.

Relative reference (A1) shifts when copied; absolute reference ($A$1) stays fixed; mixed reference ($A1 or A$1) fixes only the column or only the row.

Every formula starts with =; operators are + - * / ^ and %; e.g. =(A1+B1)*2; text is enclosed in double quotes.

Functions: =SUM(A1:A10), =AVERAGE(range), =MAX(range), =MIN(range), =COUNT(range) counts numbers, =COUNTA(range) counts non-empty cells, =ROUND(number, digits).

Logical functions: =IF(condition, value_if_true, value_if_false); conditions use =, <>, >, <, >=, <= and may combine with AND/OR/NOT.

Lookup: =VLOOKUP(lookup_value, table_range, column_index, FALSE) searches the first column and returns a value from the given column; FALSE means exact match.

Error values: #DIV/0! division by zero, #REF! invalid reference, #NAME? unrecognised name, #VALUE! wrong data type, ##### column too narrow.

Charts: column/bar compare categories, line shows trends over time, pie shows parts of a whole (one data series); sorting arranges data, filtering hides rows that fail a condition.

A presentation is a file of slides; a slide layout fixes placeholders for title, text, and objects; a slide master controls fonts and background for all slides.

Views: Normal (edit one slide), Slide Sorter (reorder slides), Notes Page (speaker notes), Slide Show (full-screen delivery); F5 starts the show from the beginning.

Transitions apply between slides; animations apply to objects within a slide; too many effects reduce readability.

Design rules: one idea per slide, about six lines with about six words each, sans-serif fonts of 24 points or more, high contrast, and no text over busy images.

Insertable objects: text box, picture, chart, table, SmartArt, audio, video, and hyperlink to a slide, file, or web page.

Digital communication channels: email (formal, asynchronous), instant messaging (quick, informal), video conferencing (synchronous, remote meeting), and social media (public broadcast).

Netiquette: clear subject line, short paragraphs, no ALL CAPS (interpreted as shouting), quote only relevant text, and avoid forwarding chain mail.

Accessibility: add alt text to images, use readable font sizes, and avoid conveying meaning by colour alone.

Internet = global network of networks using TCP/IP; the World Wide Web is one service on it; a web page is a single HTML document and a website is a collection of linked pages.

URL parts: protocol (https://), domain name (www.example.com), path (/page.html), and optional query string; DNS translates domain names into IP addresses.

Protocols: HTTP/HTTPS for web pages (HTTPS is encrypted), FTP for file transfer, SMTP for sending mail, POP3/IMAP for receiving mail.

IPv4 address = 32 bits in four dotted decimal octets (0-255); IPv6 = 128 bits; the default gateway is the router that forwards traffic outside the local network.

Browser actions: back/forward, refresh, bookmarks/favourites, history, downloads, and private/incognito mode; a search engine is not the same as a browser.

Email fields: To (main recipient), Cc (carbon copy, visible to all), Bcc (blind copy, hidden from other recipients), Subject, Body, and Attachment.

Email address form: localpart@domain (e.g., [email protected]); Reply All sends to sender plus all Cc recipients; Forward resends a received mail to new recipients.

Search tips: use quotation marks for an exact phrase, minus sign to exclude a word, and site: to restrict results to one domain.

Database = organised collection of related data; DBMS = software to create, store, retrieve, and secure it; RDBMS stores data as tables (relations) of rows (records) and columns (fields).

Keys: primary key uniquely identifies each row and cannot be null or duplicated; foreign key in one table refers to the primary key of another and enforces referential integrity.

Data types: integer/number, character/varchar/text, date, and boolean; choosing the right type saves space and prevents invalid entries.

SQL data definition: CREATE TABLE, ALTER TABLE, DROP TABLE; data manipulation: INSERT INTO, SELECT, UPDATE, DELETE.

SELECT syntax: SELECT columns FROM table WHERE condition ORDER BY column ASC|DESC; WHERE filters rows; the wildcard * selects all columns.

Aggregate functions: COUNT, SUM, AVG, MIN, MAX; GROUP BY groups rows and HAVING filters groups, while WHERE filters individual rows before grouping.

Constraints: NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK, DEFAULT; they reject invalid data at entry time.

Normalisation reduces redundancy and update anomalies: 1NF removes repeating groups (atomic values), 2NF removes partial dependency on part of a composite key, 3NF removes transitive dependency on non-key fields.

Program = ordered set of instructions; algorithm = finite step-by-step solution; flowchart symbols: oval (start/end), parallelogram (input/output), rectangle (process), diamond (decision), arrow (flow).

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

Variables are named memory locations holding a value of a data type (integer, float, string, boolean); a constant cannot change after assignment.

Operators: arithmetic (+ - * / % ^), relational (=, <>, <, >, <=, >=), logical (AND, OR, NOT), and assignment (=); % gives the remainder.

Assignment x = x + 1 means evaluate the right side first, then store the result in x; trace tables track variable values line by line.

Loops: for is used when the number of repetitions is known; while tests the condition before the body; do-while tests after, so the body runs at least once.

Arrays store many values of the same type under one name, indexed from 0 in most languages; the last index is size - 1.

Common logic errors: off-by-one in loop bounds, using = instead of == in a condition, and infinite loops when the loop variable is never updated.

Strong password: 12+ characters mixing upper and lower case, digits, and symbols, unique per account, never shared; enable two-factor authentication where offered.

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

Phishing = fraudulent email or message that imitates a trusted source to steal credentials; check the sender address and links before clicking; banks never ask for OTPs or PINs.

Cybercrime reporting in India: report at cybercrime.gov.in or call 1930; a cyber cafe must keep records of users as required by law.

Digital footprint is permanent: posts, images, and comments can be copied and indexed; think before posting and review privacy settings.

Copyright protects original work automatically on creation; using someone's image, text, or music without permission or licence is infringement; cite sources and use royalty-free or licensed material.

Plagiarism is presenting another's work or ideas as one's own; paraphrase with citation, and never copy-paste without attribution.

Netiquette and law: no hate speech, harassment, or sharing others' private data (doxxing); the IT Act 2000 covers offences such as identity theft and publishing obscene material.

Communication process: sender, message, encoding, channel, receiver, decoding, feedback; noise is any interference that distorts the message.

Self-management skills: time management (prioritise urgent and important tasks), goal setting using SMART criteria (Specific, Measurable, Achievable, Relevant, Time-bound), and stress management.

Resume/CV sections: personal details, career objective, education, skills, projects, achievements, and references; keep it truthful and free of spelling errors.

Cover letter structure: sender details, date, recipient, subject, opening stating the post applied for, body matching skills to the job, closing with a request for an interview.

Interview basics: research the organisation, dress neatly, greet politely, answer with examples, ask relevant questions, and send a thank-you note afterwards.

Entrepreneurship terms: entrepreneur takes risk to start a venture; a business plan covers product, market, finance, and operations; MSME and startup schemes support small enterprises.

Workplace safety: follow safety signs (mandatory blue, warning yellow, prohibition red), use personal protective equipment, keep exits clear, and report hazards immediately.

Green and ethical practices: reduce, reuse, recycle; save power by switching off unused devices; dispose of e-waste through authorised collection points, not household bins.