Maharashtra HSC IT Science flashcards

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

Data vs Information

Data is raw, unprocessed facts such as numbers or text. Information is data that has been processed, organized, and given meaning so it can support decisions.

Byte and bit

A bit is a single binary digit, either 0 or 1. A byte is a group of 8 bits and typically represents one character.

Hexadecimal number system

A base-16 number system using digits 0-9 and letters A-F, where A equals 10 and F equals 15. It is used as compact shorthand for binary values.

Logic gate XOR

An exclusive OR gate outputs 1 when its inputs differ, that is when an odd number of inputs are 1. It outputs 0 when inputs are identical.

CPU components

The central processing unit contains the arithmetic logic unit for calculations and comparisons, the control unit for sequencing instructions, and registers for holding current data.

Operating system definition

System software that manages hardware resources such as CPU, memory, and devices, provides a user interface, and lets application programs run on the computer.

Time-sharing operating system

A multi-user operating system that switches the CPU rapidly among users, giving each a small time slice so all appear to be served simultaneously.

Process states

The stages a process passes through: new, ready, running, waiting, and terminated. A process moves to running only when the scheduler dispatches it.

Deadlock conditions

Four conditions must hold together for deadlock: mutual exclusion, hold and wait, no preemption, and circular wait. Removing any one condition prevents deadlock.

Round robin scheduling

A preemptive CPU scheduling algorithm that gives each process a fixed time quantum in rotation. It is fair and responsive but adds context-switching overhead.

Void elements in HTML

Elements that have no content and no closing tag, such as br for a line break, hr for a horizontal rule, img for an image, and input.

HTML table tags

A table uses table for the container, tr for rows, th for header cells, and td for data cells. The caption tag gives the table a title.

CSS class vs id selector

A class selector starts with a dot and may be reused on many elements. An id selector starts with a hash and must be unique within a page.

alt attribute

Text attached to an img element that describes the image. It is read by screen readers and displayed when the image cannot be loaded.

Cloud service models

IaaS provides virtual machines and storage, PaaS provides a development and runtime platform, and SaaS provides complete applications accessed through a browser.

Internet of Things

A network of physical devices fitted with sensors and software that collect and exchange data over the internet with little or no human intervention.

5G network features

The fifth-generation mobile standard offers very high data rates, latency near one millisecond, and support for a large number of connected devices.

Machine learning

A branch of artificial intelligence in which programs learn patterns from training data and improve their predictions instead of following only explicit hand-written rules.

Cloud elasticity

The ability of a cloud service to scale computing resources up or down automatically as demand changes, so users pay for what they actually use.

let vs var in JavaScript

A variable declared with var is function-scoped and hoisted. A variable declared with let is block-scoped and exists only inside its enclosing braces.

Strict equality operator

The triple equals operator compares both value and data type without conversion, so the number 5 and the string '5' are not equal.

CSS box model

The layers around element content: padding inside the border, the border itself, and margin outside. Total width equals content plus padding plus border plus margin.

DOM in JavaScript

The Document Object Model is a tree representation of the HTML page that JavaScript can read and modify using methods such as getElementById and querySelector.

PHP superglobal arrays

Predefined arrays available in every scope: $_GET for query strings, $_POST for form bodies, $_SESSION for session data, $_COOKIE for cookies, and $_SERVER for server details.

PHP string concatenation

PHP joins strings with the dot operator, as in $a . $b. Variables inside double-quoted strings are interpolated, while single-quoted strings show them literally.

require vs include in PHP

Both insert a file into the script. require stops execution with a fatal error if the file is missing, while include only issues a warning and continues.

PHP session handling

Call session_start() before any output to begin a session, store values in $_SESSION, and call session_destroy() to end it and clear the stored data.

Primary key

A column or set of columns that uniquely identifies every row in a table. It cannot contain null values and only one primary key is allowed per table.

Foreign key

A column in one table that references the primary key of another table, enforcing referential integrity so related rows cannot be orphaned.

Third normal form

A table is in 3NF when it is in 2NF and has no transitive dependency, meaning non-key columns depend only on the primary key and not on other non-key columns.

WHERE vs HAVING

WHERE filters individual rows before grouping is performed. HAVING filters groups after GROUP BY and is used with aggregate functions such as COUNT and SUM.

IT Act Section 66C

A section of the Information Technology Act, 2000 that punishes identity theft, meaning fraudulent use of another person's electronic signature, password, or unique identification feature.