Odisha CHSE +2 Vocational Information Technology cheat sheet

von Neumann architecture: CPU (ALU + control unit + registers), memory, input, output; data and instructions share the same memory and bus.

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

Primary memory is volatile (RAM) or ROM-based; secondary storage (HDD, SSD, pen drive, DVD) is non-volatile.

ROM variants: PROM (one-time programmable), EPROM (erased by UV light), EEPROM/Flash (erased electrically).

Ports: USB, HDMI (audio + video), VGA (analog video), RJ-45 (Ethernet), 3.5 mm audio jack.

Input devices convert human data to machine form; output devices do the reverse; a touchscreen does both.

Speed units: clock speed in GHz, storage in GB/TB, network throughput in Mbps; 1 Mbps = 10^6 bits per second.

Printer classes: impact (dot matrix, line printer) vs non-impact (inkjet, laser); laser uses toner and a drum.

OS functions: process management, memory management, file system management, device management, security and user interface.

CLI vs GUI: CLI issues text commands (dir, copy, del); GUI uses windows, icons, menus and a pointer.

Windows path syntax: drive letter + colon + backslash, e.g. C:\Users\Name\file.txt; extension identifies file type.

Common extensions: .txt text, .docx Word, .xlsx Excel, .pptx PowerPoint, .exe executable, .jpg image.

Wildcards: * matches any number of characters, ? matches exactly one character (e.g. *.docx, report?.txt).

File operations: copy duplicates (Ctrl+C/Ctrl+V), move relocates (Ctrl+X/Ctrl+V), delete sends to Recycle Bin (Shift+Del bypasses it).

Shortcuts: Ctrl+S save, Ctrl+Z undo, Ctrl+A select all, Alt+Tab switch apps, Ctrl+Shift+Esc opens Task Manager.

A file system (FAT32, NTFS, exFAT) defines how data is named, stored and retrieved on a volume.

Word processor objects: character, paragraph, section, page; formatting applies at the level of the selected object.

Alignment options: left, centre, right, justified; line spacing values include single, 1.5 and double.

Styles (Heading 1, Normal) enable consistent formatting and automatic table of contents generation.

Find and Replace (Ctrl+H) substitutes text globally; Use Wildcards enables pattern matching.

Mail Merge steps: main document, data source, insert merge fields, preview, finish and merge.

Page setup controls margins, orientation (portrait/landscape), paper size (A4 = 210 x 297 mm) and headers/footers.

Tables organise tabular data; merged cells span rows or columns; Ctrl+Enter inserts a page break.

Track Changes records edits; Comments annotate without altering text; both are removed before final submission.

Cell reference types: relative A1 (adjusts on copy), absolute $A$1 (fixed), mixed $A1 or A$1 (one part fixed).

Every formula begins with = ; operators follow precedence: ^ then * / then + - ; parentheses override precedence.

Function syntax: =SUM(A1:A10), =AVERAGE(B2:B8), =COUNT (numbers only), =COUNTA (non-empty), =MAX, =MIN.

=IF(condition, value_if_true, value_if_false) returns one of two results; nested IFs handle multiple conditions.

=VLOOKUP(lookup_value, table_range, col_index, FALSE) finds an exact match in the first column of the range.

=COUNTIF(range, criteria) and =SUMIF(range, criteria, sum_range) aggregate rows matching a condition.

Charts: column for comparison, line for trend over time, pie for parts of a whole (single data series).

Sorting reorders rows; filtering hides rows that fail criteria without deleting them; freeze panes locks header rows.

Slide layout defines placeholders; Slide Master controls fonts, colours and background for all slides at once.

Transitions apply between slides; animations apply to objects within a slide; too many of either reduce clarity.

View modes: Normal (edit one slide), Slide Sorter (reorder), Notes Page (speaker notes), Slide Show (present).

F5 starts the show from the beginning; Shift+F5 starts from the current slide.

Multimedia elements: text, image (raster vs vector), audio (WAV, MP3), video (MP4, AVI), animation.

Raster images are pixel grids (resolution matters); vector images use mathematical paths and scale without blur.

File sizes: audio/video size depends on duration, bit rate and compression; higher bit rate = better quality, larger file.

Good slide design: one idea per slide, high contrast, minimum 24 pt body text, consistent theme, limited colour palette.

A database is an organised collection of related data; a DBMS is software that stores, retrieves and secures it.

Relational model: table (relation), row (tuple/record), column (attribute/field), primary key (unique identifier).

A foreign key in one table references the primary key of another table and enforces referential integrity.

Normalisation removes redundancy: 1NF atomic values, 2NF no partial dependency on part of a composite key, 3NF no transitive dependency.

SQL DDL: CREATE TABLE, ALTER TABLE, DROP TABLE; SQL DML: SELECT, INSERT, UPDATE, DELETE.

SELECT columns FROM table WHERE condition ORDER BY column ASC|DESC; WHERE filters rows before grouping.

Aggregate functions: COUNT, SUM, AVG, MIN, MAX; GROUP BY groups rows and HAVING filters groups.

Keys and constraints: PRIMARY KEY (unique + not null), UNIQUE, NOT NULL, CHECK, FOREIGN KEY.

Program = algorithm + data structures; an algorithm is a finite, unambiguous sequence of steps with defined input and output.

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

Flowchart symbols: oval = start/end, parallelogram = input/output, rectangle = process, diamond = decision, arrow = flow.

Data types: integer, float/real, character, string, boolean; a variable is a named memory location holding one type.

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

for loop suits known iteration counts; while tests the condition before the body; do-while executes at least once.

Array stores elements of the same type under one name with an index; indexing usually starts at 0.

Trace tables execute code line by line recording variable values; they are the standard tool for debugging logic.

Internet = global network of networks using TCP/IP; the World Wide Web is a service (HTTP/HTTPS) running on it.

URL anatomy: protocol://domain/path?query - e.g. https://example.com/page?id=5; DNS converts domain names to IP addresses.

HTTP is stateless request/response; HTTPS adds TLS encryption; GET sends data in the URL, POST sends it in the request body.

Web page languages: HTML (structure), CSS (presentation), JavaScript (behaviour); browsers render these into pages.

Email fields: To (recipients), Cc (visible copy), Bcc (hidden copy), Subject, Body, Attachment.

Email address form: localpart@domain, e.g. [email protected]; SMTP sends mail, POP3/IMAP retrieve it.

Search operators: quotation marks for exact phrase, site: to restrict to a domain, minus sign to exclude a term.

Netiquette: concise subject line, no all-caps, quote selectively, do not open unknown attachments.

Network topologies: star (central switch, single point of failure), bus (shared backbone), ring, mesh (redundant paths).

LAN covers a building; MAN a city; WAN spans countries; the Internet is the largest WAN.

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

Private IPv4 ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 - not routable on the public Internet.

Malware types: virus (needs a host file), worm (self-replicating over networks), Trojan (disguised as useful), ransomware (encrypts data).

Phishing is a social-engineering attack using fake messages to steal credentials; verify sender and links before clicking.

Firewall filters traffic by rules; antivirus scans for known signatures; both are updated regularly.

Password hygiene: long passphrase, unique per account, never shared; two-factor authentication adds a second proof of identity.

Practical record format: aim, apparatus/software used, procedure, observations, result and conclusion.

Word practical: create a document, apply heading styles, insert a table, add page numbers, save as .docx and export PDF.

Spreadsheet practical: enter data with labels, use formulas (=SUM, =AVERAGE, =IF), format cells, build a chart, set print area.

Presentation practical: build 5-8 slides on a topic, apply a consistent theme, add one chart or image, set slide transitions, save as .pptx.

Database practical: create a table with a primary key, insert records, run SELECT with WHERE and ORDER BY, save the query.

Hardware practical: identify CPU, RAM slots, HDD/SSD, SMPS, motherboard ports; state the function of each component.

File naming discipline: meaningful name, no spaces, correct extension, saved in the designated folder; keep a backup copy.

Viva questions typically test definitions, shortcut keys and the difference between two similar tools or terms.

Project report structure: title page, certificate, declaration, acknowledgement, contents, introduction, objectives, methodology, results, conclusion, bibliography.

A SMART objective is Specific, Measurable, Achievable, Relevant and Time-bound; state at least two per project.

Communication process: sender, message, channel, receiver, feedback; barriers include noise, jargon and poor listening.

Resume essentials: contact details, objective, education, skills, projects, achievements, references; keep it to one or two pages.

Cover-letter structure: post applied for, source of the vacancy, matching skills with evidence, request for an interview, polite close.

Interview preparation: research the organisation, rehearse a self-introduction, prepare examples using Situation-Task-Action-Result.

Teamwork and workplace ethics: punctuality, honesty, respecting deadlines, giving credit, reporting problems early.

Entrepreneurship basics: identify a need, survey demand, estimate cost and price, prepare a simple business plan, know local support schemes.