Odisha CHSE +2 Vocational Computer Technique cheat sheet

Decimal to binary: divide by 2 repeatedly, record remainders, and read them bottom-up; 13 becomes 1101.

Binary to decimal: add each bit multiplied by 2 raised to its position, starting at position 0 from the right; 1011 equals 11.

Hexadecimal to binary: replace each hex digit with a 4-bit group; A is 1010 and F is 1111, padding on the left when needed.

In binary multiples, 1 KB = 1024 bytes, 1 MB = 1024 KB, and 1 GB = 1024 MB; storage marketing may use decimal powers.

ASCII uses 7 bits for 128 codes; extended ASCII uses 8 bits; Unicode assigns code points for multilingual text.

AND outputs 1 only when all inputs are 1; OR outputs 1 when any input is 1; NOT inverts; XOR outputs 1 for an odd number of 1s.

In two's complement, negate a number by inverting all bits and adding 1; an n-bit signed range is -2^(n-1) to 2^(n-1)-1.

The CPU cycle is fetch, decode, execute, and store; the ALU performs arithmetic and logic while the control unit coordinates operations.

A file path is absolute when it starts at the root (C:\ or /); a relative path starts at the current directory.

FAT32 has a maximum file size of 4 GB minus 1 byte; NTFS supports larger files, and exFAT is designed for flash drives.

Common extensions include .exe for executables, .txt for text, .docx for Word, .xlsx for Excel, .pptx for PowerPoint, and .mdb for Access databases.

Windows shortcuts include Ctrl+C copy, Ctrl+X cut, Ctrl+V paste, Ctrl+Z undo, and Shift+Delete permanent delete.

Linux permissions use rwx values 4+2+1 for owner, group, and others; chmod 755 gives rwxr-xr-x.

Operating-system functions include process management, memory management, file management, device management, and the user interface.

Virtual memory uses secondary storage to extend RAM; excessive paging lowers throughput and causes thrashing.

A typical boot sequence is POST, locate the boot device, load the bootloader, load the kernel, and start services.

Ctrl+B applies bold, Ctrl+I applies italic, and Ctrl+U applies underline; Ctrl+E centers, Ctrl+L left-aligns, Ctrl+R right-aligns, and Ctrl+J justifies.

Font size is measured in points; 1 point equals 1/72 inch.

Mail merge combines a main document with a data source and inserts merge fields for each record.

Headers and footers repeat on pages; section breaks allow different headers, margins, orientation, or columns.

Find and replace can match case and whole words; wildcard support depends on the word processor.

Track Changes records insertions, deletions, and comments; accepting or rejecting changes finalizes the document.

A table of contents is generated from heading styles and must be updated after edits change page numbers or headings.

A cell reference such as A1 means column A and row 1; $A$1 is absolute, A$1 fixes the row, and $A1 fixes the column.

SUM adds a range, AVERAGE calculates the mean, COUNT counts numeric cells, COUNTA counts non-empty cells, and COUNTBLANK counts blanks.

IF(logical_test, value_if_true, value_if_false) returns one of two results; nested IF handles multiple conditions.

VLOOKUP(lookup_value, table_array, col_index_num, FALSE) searches the first column and returns an exact match from a specified column.

A formula begins with =; & joins text; operator precedence is parentheses, exponent, multiplication/division, then addition/subtraction.

Column charts compare categories, line charts show trends over time, and pie charts show parts of a whole for limited categories.

Sorting rearranges rows by a key; filtering hides nonmatching rows without deleting them.

Relative references adjust when copied; absolute references remain fixed.

A primary key uniquely identifies each row, cannot be NULL, and must be unique; a foreign key references a primary key in another table.

SQL query form: SELECT columns FROM table WHERE condition ORDER BY column ASC or DESC.

DDL includes CREATE, ALTER, and DROP; DML includes INSERT, UPDATE, and DELETE; DCL includes GRANT and REVOKE; TCL includes COMMIT and ROLLBACK.

1NF requires atomic values; 2NF removes partial dependency on a composite key; 3NF removes transitive dependency.

INNER JOIN returns matching rows from both tables; LEFT JOIN keeps all rows from the left table and matches where possible.

DELETE removes rows, DROP removes a table structure and its data, and TRUNCATE removes all rows faster than DELETE.

A DBMS controls redundancy, concurrency, integrity, backup and recovery, and security better than a file system.

An ER model uses entities, attributes, and relationships; cardinality is 1:1, 1:N, or M:N.

The slide master stores fonts, colors, logos, and placeholder positions for all slides that use it.

Transitions apply between slides; animations apply to objects within a slide.

1920x1080 is a 16:9 resolution; 1024x768 is a 4:3 resolution.

Bitmap images store pixels and can show pixelation when enlarged; vector images store paths and scale without pixelation.

JPEG is lossy for photos, PNG is lossless and supports transparency, GIF supports 256 colors and animation, MP3 is lossy audio, and WAV is uncompressed audio.

Frame rate is measured in frames per second; higher rates make motion smoother but increase file size.

Multimedia elements include text, graphics, audio, video, and animation; hyperlinks can connect slides or external files.

IPv4 addresses are 32-bit dotted decimal; IPv6 addresses are 128-bit hexadecimal.

DNS maps domain names to IP addresses; a URL has the form scheme://host/path?query.

Default ports include HTTP 80, HTTPS 443, FTP 21, SMTP 25 or 587, POP3 110, and IMAP 143.

Email fields include To, Cc, and Bcc; Bcc hides recipient addresses from other recipients, and attachments use MIME encoding.

Search operators include site:, filetype:, quoted phrases for exact matches, and - to exclude terms.

A browser retrieves and renders pages; a search engine indexes content and returns links to pages.

Cookies store small client-side data; cache stores copies of resources to reduce load time.

Bandwidth is maximum data rate, latency is delay, and ping measures round-trip time.

A C program starts at main(); statements end with a semicolon, and braces delimit blocks.

C data types include int, float, double, and char; sizeof gives byte size; format specifiers include %d, %f, %lf, %c, and %s.

BASIC uses PRINT, INPUT, LET, IF...THEN, and FOR...NEXT; line numbers are optional in modern BASIC.

A for loop suits known iteration counts, while loops test before each iteration, and do-while loops test after each iteration; break exits and continue skips.

C array indexes start at 0; array size is fixed at declaration, and bounds are not automatically checked.

A function returns a value with return, and a prototype declares its return type and parameter types before use.

In C, = assigns and == compares; && is AND, || is OR, ! is NOT, and integer division truncates.

An algorithm is stepwise text; a flowchart uses standard symbols: oval for start/end, parallelogram for input/output, rectangle for process, and diamond for decision.

CPU sockets must match the motherboard; DDR4 and DDR5 RAM are not interchangeable, and slot type must be checked.

HDDs use mechanical platters; SSDs use flash memory and offer faster access, shock resistance, and limited write cycles.

A PSU wattage rating must exceed the estimated system load; 80 PLUS ratings indicate efficiency.

Motherboard form factors include ATX, micro-ATX, and mini-ITX; case and PSU compatibility must be checked.

BIOS or UEFI firmware initializes hardware; UEFI supports GPT disks larger than 2 TB and Secure Boot.

USB 2.0 runs at 480 Mbps, USB 3.0 at 5 Gbps, HDMI carries audio and video, and RJ-45 is used for Ethernet.

Thermal paste improves heat transfer between a CPU and heatsink; overheating causes throttling or shutdown.

POST beep codes diagnose hardware faults; no power or no beep can indicate a PSU or motherboard issue.

Ping tests reachability and round-trip time; loopback 127.0.0.1 tests the local TCP/IP stack.

ipconfig /all shows IP address, MAC address, gateway, and DNS; ipconfig /release and /renew refresh DHCP settings.

tracert shows the path and latency per hop; nslookup queries DNS records.

Private IPv4 ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16; these are not routed on the public Internet.

A subnet mask separates network and host bits; /24 equals 255.255.255.0 and allows 254 usable hosts.

A straight-through cable connects dissimilar devices; a crossover cable connects similar devices in legacy networks, and Auto-MDIX removes the distinction.

DHCP assigns IP settings automatically; APIPA 169.254.x.x indicates DHCP failure; the default gateway routes traffic off-subnet.

Layer-by-layer troubleshooting checks physical link, IP configuration, DNS, firewall, and application.

Versioned backups preserve previous states; a crash during a macro or system change can discard unsaved work.

In Word, Insert > Table creates a table; merge cells combines selected cells; row height and column width adjust layout.

In Excel, the formula bar edits the active cell's formula; Ctrl+` toggles between formula view and value view.

In a DBMS, CREATE TABLE defines columns and constraints; INSERT adds records; SELECT verifies stored data before export.

In presentation software, the slide master controls consistent design; F5 starts the slideshow from the first slide.

A ZIP archive reduces file size; extract contents before editing; a checksum verifies file integrity when provided.

Print preview shows margins, orientation, page size, and page breaks before a print job is sent.

A project report commonly contains title page, certificate, acknowledgement, contents, introduction, methodology, results, conclusion, and bibliography.

Source citations and credit for reused code or data are required; uncredited copying can invalidate a project.

A viva expects a clear problem statement, tools used, modules, test cases, limitations, and a working demonstration.

Project deliverables include source code, database backup, screenshots, and a user guide.

Test cases cover valid, invalid, and boundary inputs; each records expected output and actual output.

Dated backups or version control track changes; final submission follows the specified media and deadline.

Evaluation commonly weights report quality, working demo, viva answers, and originality.