Kerala Plus Two Computer Applications (DHSE) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

2's complement range

For n-bit signed integers stored in 2's complement, the representable range is −2^(n−1) to 2^(n−1)−1; for 8 bits that is −128 to +127.

Hexadecimal conversion

Convert binary to hexadecimal by grouping bits in fours from the radix point; 10101111₂ becomes 1010 1111 = AF₁₆.

ASCII vs Unicode

ASCII uses 7 bits for 128 characters; Unicode assigns a code point to every character in the world's scripts and is encoded as UTF-8 or UTF-16.

Von Neumann architecture

A computer design in which the CPU (ALU plus control unit and registers), memory, and I/O share a bus, and instructions and data are stored in the same memory.

Compiler vs interpreter

A compiler translates the entire source program to machine code before execution; an interpreter translates and executes one statement at a time, so errors surface during execution.

Multitasking

An operating-system technique that gives each ready process a short CPU time slice in turn, creating the illusion that several programs run at the same time.

OSI layers

The seven OSI layers from bottom to top are Physical, Data Link, Network, Transport, Session, Presentation, and Application; each provides services to the layer above.

Full-duplex transmission

A transmission mode in which data can travel in both directions simultaneously, such as a telephone call or a modern Ethernet link.

IPv4 address

A 32-bit logical address written as four decimal octets separated by dots, for example 192.168.1.10, identifying a host on an IP network.

DNS

The Domain Name System maps human-readable domain names such as example.com to numeric IP addresses by querying a hierarchy of name servers.

HTTPS

Hypertext Transfer Protocol Secure carries HTTP over TLS on port 443, encrypting traffic and authenticating the server so data cannot be read or altered in transit.

Cookie

A small piece of text a website asks the browser to store and return on later requests, commonly used to remember login state, preferences, or shopping carts.

HTML anchor element

The <a href="url">text</a> tag creates a hyperlink; adding target="_blank" opens the destination in a new browser tab.

CSS box model

Every element is rendered as content surrounded by padding, then border, then margin; box-sizing:border-box makes width include padding and border.

CSS specificity

When rules conflict, the browser applies the most specific selector: inline style beats ID, which beats class, which beats element selectors; later equal rules win.

Mail merge

A word-processing feature that combines one main document containing fixed text and placeholders with a data source of records to produce personalised letters or labels.

Section break

A word-processing marker that starts a new document section, allowing different page orientation, headers, footers, or page numbering from the preceding section.

Absolute cell reference

A spreadsheet reference such as $A$1 whose row and column stay fixed when the formula is copied or filled to other cells.

VLOOKUP

A spreadsheet function that searches the first column of a table for a value and returns a cell from a specified column of the matching row; FALSE forces an exact match.

Primary key

A column or minimal set of columns that uniquely identifies each row of a table, cannot contain NULL, and is chosen from the candidate keys.

Referential integrity

A database rule requiring every foreign-key value to match an existing primary-key value in the referenced table, or to be NULL, preventing orphan records.

WHERE vs HAVING

WHERE filters individual rows before grouping in SQL; HAVING filters groups after GROUP BY and is typically used with aggregate functions such as COUNT or SUM.

Binary search

A search on sorted data that compares the target with the middle element and discards half the remaining elements each step, giving O(log n) time.

Flowchart decision symbol

A diamond shape in a flowchart represents a decision; it has one input and two or more labelled outputs such as Yes and No.

do-while loop

A C loop that executes its body once before testing the condition, so the body always runs at least one time even if the condition is initially false.

C string terminator

In C a string is a char array ending with the null character '\0', which marks the end of the text for library functions such as printf and strlen.

Modulus operator

The C operator % returns the remainder of integer division; 17 % 5 evaluates to 2, and it cannot be applied to floating-point operands.

UPI

Unified Payments Interface is an Indian instant payment system that lets users transfer money between bank accounts using a virtual payment address on a mobile app.

Digital divide

The gap between people who have effective access to information and communication technology and those who lack devices, connectivity, or skills.

Phishing

A social-engineering attack in which a fraudulent email, message, or website impersonates a trusted party to trick users into revealing passwords or financial details.

Ransomware

Malicious software that encrypts a victim's files or locks the system and demands payment, often in cryptocurrency, for the decryption key.

IT Act 2000

India's Information Technology Act, amended in 2008, gives legal recognition to electronic records and digital signatures and defines cyber offences and penalties.