Class 11 Computer Science: Computer System, Boolean Logic, Number Systems & Python Basics

Vocabulary flashcards covering fundamental terms from computer organisation, Boolean logic, number systems, and Python programming as discussed in the lecture notes.

Computer

An electronic device that accepts data, processes it under program control, and outputs results.

Computer System

A computer along with its associated hardware and software working together.

Input Device

Hardware that converts user input into digital form acceptable to the computer (e.g., keyboard, mouse).

Output Device

Hardware that converts digital information into human-understandable form (e.g., monitor, printer).

CPU (Central Processing Unit)

Electronic circuitry that performs actual processing; called the brain of the computer.

ALU (Arithmetic & Logic Unit)

CPU component that performs arithmetic calculations and logical comparisons.

Control Unit

CPU component that interprets instructions and directs data flow among ALU, memory and I/O.

Primary Memory

Fast, volatile storage directly accessed by CPU; includes RAM and cache.

Secondary Memory

Non-volatile, large-capacity storage for long-term data (e.g., hard disk, SSD, CD).

RAM (Random Access Memory)

Volatile primary memory that temporarily holds data & instructions while the computer is on.

ROM (Read Only Memory)

Non-volatile memory that stores permanent instructions such as the boot loader.

Cache Memory

Very high-speed memory between CPU and RAM that stores frequently accessed data to speed up processing.

Hardware

Physical components of a computer that can be seen and touched.

Software

Set of instructions and data that make hardware functional.

System Software

Software that manages hardware and provides a platform for applications (e.g., OS, utilities, drivers).

Operating System

System software that manages hardware, runs other programs, and provides user interfaces (e.g., Windows, Linux).

System Utility

Maintenance/configuration program that improves system performance (e.g., antivirus, disk cleaner).

Device Driver

System software that acts as an interface between OS and specific hardware devices.

Application Software

Programs designed to perform specific user tasks such as word processing or photo editing.

General Purpose Software

Ready-made applications for a broad audience (e.g., Adobe Photoshop).

Customized Software

Tailor-made applications for a particular organization or individual (e.g., school management system).

FOSS (Free & Open Source Software)

Software whose source code is freely available for use and modification (e.g., LibreOffice, Python).

Freeware

Software available at no cost but without source code (e.g., Adobe Reader, Skype).

Proprietary Software

Commercial software that must be purchased and is protected by copyright (e.g., Microsoft Windows).

Low-Level Language

Machine-dependent language directly understood by hardware (machine & assembly).

Machine Language

Binary code executed directly by the CPU; hardest for humans to write.

Assembly Language

Low-level language using mnemonic codes; requires an assembler; CPU-specific.

High-Level Language

Machine-independent language using English-like syntax; requires translation (e.g., C++, Python).

Language Translator

Software that converts code from one language to another, usually to machine code.

Assembler

Translator that converts assembly language into machine language.

Compiler

Translator that converts entire high-level source code into machine code before execution.

Interpreter

Translator that converts and executes high-level code line-by-line at run time.

Source Code

Program statements written by the programmer in a high-level or assembly language.

Object/Machine Code

Translated, executable form of a program produced by a compiler or assembler.

Boolean Algebra

Algebra of two values (0,1) introduced by George Boole, used in logic circuits.

AND Operation

Boolean operation that outputs 1 only if all inputs are 1.

OR Operation

Boolean operation that outputs 1 if at least one input is 1.

NOT Operation

Boolean operation that inverts a single input (0→1, 1→0).

Logic Gate

Electronic circuit implementing a Boolean operation and producing a logical output.

NOT Gate

Single-input logic gate that outputs the complement of the input.

OR Gate

Logic gate that outputs 1 when any input is 1 (logical addition).

AND Gate

Logic gate that outputs 1 only when all inputs are 1 (logical multiplication).

NAND Gate

Gate whose output is the complement of AND; outputs 0 only when all inputs are 1.

NOR Gate

Gate whose output is the complement of OR; outputs 1 only when all inputs are 0.

De Morgan’s First Law

¬(X + Y) = ¬X · ¬Y (complement of OR equals AND of complements).

De Morgan’s Second Law

¬(X·Y) = ¬X + ¬Y (complement of AND equals OR of complements).

Encoding Scheme

System for representing characters in binary form (e.g., ASCII, Unicode).

ASCII

7-bit character code for English letters and symbols (128 possible values).

ISCII

8-bit Indian Standard Code for Information Interchange supporting Indian scripts.

Unicode

Universal character encoding standard; common UTF forms are UTF-8, UTF-16, UTF-32.

Decimal System

Base-10 number system using digits 0–9.

Binary System

Base-2 number system using digits 0 and 1.

Octal System

Base-8 number system using digits 0–7.

Hexadecimal System

Base-16 number system using digits 0–9 and letters A–F.

Python

General-purpose, high-level, interpreted, open-source language created by Guido van Rossum.

IDLE

Python’s Integrated Development and Learning Environment for typing, debugging, executing code.

Token (Python)

Smallest meaningful element in Python code: keywords, identifiers, literals, operators, punctuators.

Keyword (Python)

Reserved word with special meaning in Python (e.g., if, while, True).

Identifier (Python)

Name given to variables, functions, etc.; may include letters, digits, underscore but not start with digit.

Literal (Python)

Constant value written directly in code (e.g., 123, 'hello').

String Literal

Sequence of characters enclosed in single, double, or triple quotes.

Numeric Literal

Number written in code; can be int, float, or complex.

Special Literal

The value None, representing absence of a value in Python.

int() Function

Built-in that converts a number or numeric string to integer; truncates float part.

float() Function

Built-in that converts a number or numeric string to floating-point value.

eval() Function

Built-in that evaluates a string as a Python expression and returns the result.

print() Function

Built-in that outputs objects to the screen; supports sep and end arguments.

Variable (Python)

Named location referring to data stored in memory; dynamically typed.

type() Function

Built-in that returns the data type of an object.

id() Function

Built-in that returns the unique memory address (identity) of an object.

Comment (Python)

Non-executing text; starts with # for single line or triple quotes for multi-line.

Operator

Symbol that performs computation on operands.

Arithmetic Operator

Performs mathematical operations (+, -, *, /, **, %).

Relational Operator

Compares values and returns boolean (==, !=,

Logical Operator

Combines boolean values (and, or, not).

Membership Operator

Tests membership in a sequence (in, not in).

Assignment Operator

Assigns values to variables (=, +=, -=, etc.).

Unary Operator

Operator acting on a single operand (e.g., unary minus).

Binary Operator

Operator acting on two operands (most arithmetic, relational, logical operators).